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Blaess M, Kaiser L, Sommerfeld O, Csuk R, Deigner HP. Drug triggered pruritus, rash, papules, and blisters - is AGEP a clash of an altered sphingolipid-metabolism and lysosomotropism of drugs accumulating in the skin? Lipids Health Dis 2021; 20:156. [PMID: 34743684 PMCID: PMC8573906 DOI: 10.1186/s12944-021-01552-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Accepted: 09/09/2021] [Indexed: 11/26/2022] Open
Abstract
Rash, photosensitivity, erythema multiforme, and the acute generalized exanthematous pustulosis (AGEP) are relatively uncommon adverse reactions of drugs. To date, the etiology is not well understood and individual susceptibility still remains unknown. Amiodarone, chlorpromazine, amitriptyline, and trimipramine are classified lysosomotropic as well as photosensitizing, however, they fail to trigger rash and pruritic papules in all individuals. Lysosomotropism is a common charcteristic of various drugs, but independent of individuals. There is evidence that the individual ability to respond to external oxidative stress is crosslinked with the elongation of long-chain fatty acids to very long-chain fatty acids by ELOVLs. ELOVL6 and ELOVL7 are sensitive to ROS induced depletion of cellular NADPH and insufficient regeneration via the pentose phosphate pathway and mitochondrial fatty acid oxidation. Deficiency of NADPH in presence of lysosomotropic drugs promotes the synthesis of C16-ceramide in lysosomes and may contribute to emerging pruritic papules of AGEP. However, independently from a lysosomomotropic drug, severe depletion of ATP and NAD(P)H, e.g., by UV radiation or a potent photosensitizer can trigger likewise the collapse of the lysosomal transmembrane proton gradient resulting in lysosomal C16-ceramide synthesis and pruritic papules. This kind of papules are equally present in polymorphous light eruption (PMLE/PLE) and acne aestivalis (Mallorca acne). The suggested model of a compartmentalized ceramide metabolism provides a more sophisticated explanation of cutaneous drug adverse effects and the individual sensitivity to UV radiation. Parameters such as pKa and ClogP of the triggering drug, cutaneous fatty acid profile, and ceramide profile enables new concepts in risk assessment and scoring of AGEP as well as prophylaxis outcome.
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Affiliation(s)
- Markus Blaess
- Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, Jakob-Kienzle-Str. 17, D-78054, Villingen-Schwenningen, Germany
| | - Lars Kaiser
- Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, Jakob-Kienzle-Str. 17, D-78054, Villingen-Schwenningen, Germany
- Institute of Pharmaceutical Sciences, University of Freiburg, Albertstraße 25, D-79104, Freiburg, Germany
| | - Oliver Sommerfeld
- Department of Anaesthesiology and Intensive Care Medicine, Jena University Hospital, Am Klinikum 1, D-07747, Jena, Germany
| | - René Csuk
- Organic Chemistry, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Straße 2, D-06120, Halle (Saale), Germany
| | - Hans-Peter Deigner
- Institute of Precision Medicine, Medical and Life Sciences Faculty, Furtwangen University, Jakob-Kienzle-Str. 17, D-78054, Villingen-Schwenningen, Germany.
- EXIM Department, Fraunhofer Institute IZI, Schillingallee 68, D-18057, Leipzig, Rostock, Germany.
- Faculty of Science, Associated member of Tuebingen University, Auf der Morgenstelle 8, D- 72076, Tübingen, Germany.
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Jansen T, Hoegberg LCG, Eriksen T, Dalhoff KP, Belhage B, Johansen SS. Amitriptyline accumulation in tissues after coated activated charcoal hemoperfusion-a randomized controlled animal poisoning model. Naunyn Schmiedebergs Arch Pharmacol 2019; 392:1285-1292. [PMID: 31187186 DOI: 10.1007/s00210-019-01669-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 05/16/2019] [Indexed: 11/28/2022]
Abstract
Amitriptyline poisoning (AT) is a common poisoning, and AT possess the ability to promote life-threatening complications by its main action on the central nervous and cardiovascular systems. The pharmacokinetic properties might be altered at toxic levels compared to therapeutic levels. The effect of coated activated charcoal hemoperfusion (CAC-HP) on the accumulation of AT and its active metabolite nortriptyline (NT) in various tissues was studied in a non-blinded randomized controlled animal trial including 14 female Danish Land Race piglets. All piglets were poisoned with amitriptyline 7.5 mg/kg infused in 20 min, followed by orally instilled activated charcoal at 30 min after infusion cessation. The intervention group received 4 h of CAC-HP followed by a 1-h redistribution phase. At study cessation, the piglets were euthanized, and within 20 min, vitreous fluid, liver tissue, ventricle and septum of the heart, diaphragm and lipoic and brain tissues were collected. AT and NT tissue concentrations were quantified by UHPLC-MS/MS. A 4-h treatment with CAC-HP did not affect the tissue accumulation of AT in the selected organs when tested by Mann-Whitney U test (p values between 0.44 and 0.73). For NT concentrations, p values were between 0.13 and 1.00. Although not significant, an interesting finding was that data showed a tendency of increased tissue accumulation of AT and NT in the CAC-HP group compared with the control group. Coated activated charcoal hemoperfusion does not significantly alter the tissue concentration of AT and NT in the AT-poisoned piglet.
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Affiliation(s)
- Tejs Jansen
- Department of Anaesthesia and Intensive Care, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, Building 7A, NV, 2400, Copenhagen, Denmark.
| | - Lotte C G Hoegberg
- Department of Anaesthesia and Intensive Care, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, Building 7A, NV, 2400, Copenhagen, Denmark
| | - Thomas Eriksen
- Department of Veterinary Clinical Sciences, University Hospital for Companion Animals, Faculty of Health and Medical Sciences, University of Copenhagen, Dyrlægevej 16, 1870, Frederiksberg, Denmark
| | - Kim P Dalhoff
- Department of Clinical Pharmacology, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, Building 20C, NV, 2400, Copenhagen, Denmark
| | - Bo Belhage
- Department of Anaesthesia and Intensive Care, Copenhagen University Hospital Bispebjerg, Bispebjerg Bakke 23, Building 7A, NV, 2400, Copenhagen, Denmark
| | - Sys S Johansen
- Department of Forensic Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Frederik V's Vej 11, 2100, Copenhagen, Denmark
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Kondratenko SN, Savelyeva MI, Kukes VG, Shikh EV, Gneushev ET. Experimental and Clinical Pharmacokinetics of Fluoxetine and Amitriptyline: Comparative Analysis and Possible Methods of Extrapolation. Bull Exp Biol Med 2019; 167:356-362. [PMID: 31346879 DOI: 10.1007/s10517-019-04526-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Indexed: 11/30/2022]
Abstract
The pharmacokinetics of two fluoxetine capsulated dosage forms and two amitriptyline tablet forms after a single oral intake was studied in dogs and healthy volunteers. High significant correlations were detected between plasma concentrations of fluoxetine (r=0.96, p<0.00001, n=11) and amitriptyline (r=0.78, p<0.0224, n=8) in dogs and volunteers. A correlation of medium strength (though insignificant) was detected between nortriptyline concentrations in the plasma of dogs and volunteers (r=0.69, p<0.199, n=5). The bioavailability parameters of the test drugs in dogs and volunteers did not differ. Similar trends of fluoxetine and amitriptyline pharmacokinetic parameters were revealed in volunteers and animals. Methods for extrapolation of experimental pharmacokinetics parameters of fluoxetine and amitriptyline obtained on dogs for humans are proposed and validated.
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Affiliation(s)
- S N Kondratenko
- Department of Clinical Pharmacology and Propaedeutics of Internal Diseases, I. M. Sechenov First Moscow State Medical University (Sechenov University), Ministry of Health of the Russian Federation, Moskva, Russia.
| | - M I Savelyeva
- Department of Clinical Pharmacology and Therapy, Russian Medical Academy for Continuous Professional Education, Ministry of Health of the Russian Federation, Moscow, Russia
| | - V G Kukes
- Department of Clinical Pharmacology and Propaedeutics of Internal Diseases, I. M. Sechenov First Moscow State Medical University (Sechenov University), Ministry of Health of the Russian Federation, Moskva, Russia
| | - E V Shikh
- Department of Clinical Pharmacology and Propaedeutics of Internal Diseases, I. M. Sechenov First Moscow State Medical University (Sechenov University), Ministry of Health of the Russian Federation, Moskva, Russia
| | - E T Gneushev
- Laboratory of Drug Toxicology, National Medical Research Center of Cardiology, Ministry of Health of the Russian Federation, Moscow, Russia
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Tylutki Z, Mendyk A, Polak S. Physiologically based pharmacokinetic-quantitative systems toxicology and safety (PBPK-QSTS) modeling approach applied to predict the variability of amitriptyline pharmacokinetics and cardiac safety in populations and in individuals. J Pharmacokinet Pharmacodyn 2018; 45:663-677. [PMID: 29943290 PMCID: PMC6182726 DOI: 10.1007/s10928-018-9597-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 06/22/2018] [Indexed: 12/17/2022]
Abstract
The physiologically based pharmacokinetic (PBPK) models allow for predictive assessment of variability in population of interest. One of the future application of PBPK modeling is in the field of precision dosing and personalized medicine. The aim of the study was to develop PBPK model for amitriptyline given orally, predict the variability of cardiac concentrations of amitriptyline and its main metabolite-nortriptyline in populations as well as individuals, and simulate the influence of those xenobiotics in therapeutic and supratherapeutic concentrations on human electrophysiology. The cardiac effect with regard to QT and RR interval lengths was assessed. The Emax model to describe the relationship between amitriptyline concentration and heart rate (RR) length was proposed. The developed PBPK model was used to mimic 29 clinical trials and 19 cases of amitriptyline intoxication. Three clinical trials and 18 cases were simulated with the use of PBPK-QSTS approach, confirming lack of cardiotoxic effect of amitriptyline in therapeutic doses and the increase in heart rate along with potential for arrhythmia development in case of amitriptyline overdose. The results of our study support the validity and feasibility of the PBPK-QSTS modeling development for personalized medicine.
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Affiliation(s)
- Zofia Tylutki
- Unit of Pharmacoepidemiology and Pharmacoeconomics, Department of Social Pharmacy, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Str., 30-688, Krakow, Poland.
| | - Aleksander Mendyk
- Department of Pharmaceutical Technology and Biopharmaceutics, Jagiellonian University Medical College, Medyczna 9 St, 30-688, Krakow, Poland
| | - Sebastian Polak
- Unit of Pharmacoepidemiology and Pharmacoeconomics, Department of Social Pharmacy, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Str., 30-688, Krakow, Poland
- Certara-Simcyp, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
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Bryson E, Hartman R, Arnold J, Gorman G, Sweitzer S, Asbill S. Skin Permeation and Antinociception of Compounded Topical Cyclobenzaprine Hydrochloride Formulations. Int J Pharm Compd 2015; 19:161-166. [PMID: 26685496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Cyclobenzaprine has been commonly compounded by pharmacists into topically applied dosage forms for the treatment of pain disorders. However, the efficacy and transdermal penetration of topically applied compounded cyclobenzaprine is currently unknown. In this study, the transdermal penetration of cyclobenzaprine was studied in Franz diffusion cells using porcine skin. Cyclobenzaprine was compounded in two commercially available bases; Lipobase, Lipoderm, and a standard poloxamer lecithin organogel. In addition, cyclobenzaprine was tested in an in vivo formalin pain model. Cyclobenzaprine 5% compounded into all three bases yielded significant transdermal penetration and results in modest levels of cyclobenzaprine being retained in the skin tissue. Systemically administered cyclobenzaprine (10 mcg/kg), but not topically administered cyclobenzaprine (1% and 5%), attenuated nociception in a rodent formalin pain model.
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Paksu S, Duran L, Altuntas M, Zengin H, Salis O, Ozsevik SN, Albayrak H, Murat N, Guzel A, Paksu MS. Amitriptyline overdose in emergency department of university hospital: evaluation of 250 patients. Hum Exp Toxicol 2014; 33:980-90. [PMID: 24505046 DOI: 10.1177/0960327113520019] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
OBJECTIVE The purpose of this study was to evaluate the patients with acute amitriptyline poisoning and investigate predictive factors for the development of life-threatening complications. METHODS Demographics, clinical, laboratory, and electrocardiographic (ECG) findings of 250 patients were evaluated retrospectively. Predictive parameters for the development of serious complications were studied. RESULTS Median age of patients was 14.6 years, of which, 70% of patients were female and 66% were in pediatric age group. The most common pathological clinical finding and laboratory abnormality were alteration of consciousness and hyponatremia. The rate of convulsive seizure, arrhythmia, and respiratory depression were 17 (6.8%), 16 (6.4%), and 11 (4.4%), respectively. These complications were more seen in pediatric patients than adults (15.8% and 1.2%). The incidence of hyponatremia was more in pediatric patients and severe poisoning groups (38.8 and 53.4%, respectively). The levels of amitriptyline and nortriptyline were significantly higher in the group with complications than the group without complications (p < 0.05). All adult patients were discharged with good prognosis. In pediatric age group, one patient was discharged with severe neurological sequelae and one patient died. QRS duration >100 ms, long corrected QT duration interval, and low Glasgow Coma Score (GCS) at admission were identified as independent risk factors for the development of life-threatening complications (odds ratio: 69.4, 1.9, and 1383, respectively; p < 0.05). CONCLUSION Amitriptyline poisoning may be associated with life-threatening complications, especially in pediatric age group and in patients with hyponatremia. Low GCS, presence of hyponatremia, high serum drug levels, and pathological ECG findings on admission may be helpful in predicting the development of complications and poor prognosis.
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Affiliation(s)
- S Paksu
- Department of Pediatrics, Faculty of Medicine, Ondokuz Mayis University, Atakum, Samsun, Turkey
| | - L Duran
- Department of Emergency Medicine, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - M Altuntas
- Department of Cardiology, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - H Zengin
- Department of Biochemistry, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - O Salis
- Department of Pediatrics, Faculty of Medicine, Ondokuz Mayis University, Atakum, Samsun, Turkey
| | - S N Ozsevik
- Department of Pediatrics, Faculty of Medicine, Ondokuz Mayis University, Atakum, Samsun, Turkey
| | - H Albayrak
- Department of Pediatrics, Faculty of Medicine, Ondokuz Mayis University, Atakum, Samsun, Turkey
| | - N Murat
- Department of Industrial Engineering, Faculty of Engineering, Ondokuz Mayis University, Samsun, Turkey
| | - A Guzel
- Department of Pediatric Emergency, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - M S Paksu
- Pediatric Intensive Care Unit, Faculty of Medicine, Ondokuz Mayis University, Samsun, Turkey
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Abstract
Medico-legal autopsy is the primary method in determining the cause and manner of death when the death is suspected to be unnatural. In some of these autopsies, the death remains ambiguous, even after a complete autopsy including histological investigation and toxicological screenings. In cases where there are no morphological abnormalities, medico-legal genetics may offer additional means to provide knowledge of possible genetic mutations, which may have initiated the process or predisposed the individual to stress risk conditions leading to death. One class of ambiguous deaths consists of drug-related deaths where the interpretation of the toxicological results are not clear. In such situations post mortem genotyping and the analysis of metabolite rations may provide an insight to the findings. A few cases demonstrating the potential strength of pharmacogenetics in medico-legal context has been published. However, there is a paramount need for serious scientific studies before the field of post mortem pharmacogenetics can be utilized in routine medico-legal analyses casework and brought routinely into courtroom.
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Affiliation(s)
- A Sajantila
- Hjelt Institute, Department of Forensic Medicine, P.O. Box 14, University of Helsinki, Finland.
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Nojimoto FD, Mueller A, Hebeler-Barbosa F, Akinaga J, Lima V, Kiguti LRDA, Pupo AS. The tricyclic antidepressants amitriptyline, nortriptyline and imipramine are weak antagonists of human and rat alpha1B-adrenoceptors. Neuropharmacology 2010; 59:49-57. [PMID: 20363235 DOI: 10.1016/j.neuropharm.2010.03.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/24/2010] [Accepted: 03/26/2010] [Indexed: 12/11/2022]
Abstract
Although it is long known that the tricyclic antidepressants amitriptyline, nortriptyline and imipramine inhibit the noradrenaline transporter and alpha(1)-adrenoceptors with similar affinities, which may lead to self-cancelling actions, the selectivity of these drugs for alpha(1)-adrenoceptor subtypes is unknown. The present study investigates the selectivity of amitriptyline, nortriptyline and imipramine for human recombinant and rat native alpha(1)-adrenoceptor subtypes. The selectivity of amitriptyline, nortriptyline and imipramine was investigated in HEK-293 cells expressing each of the human alpha(1)-subtypes and in rat native receptors from the vas deferens (alpha(1A)), spleen (alpha(1B)) and aorta (alpha(1D)) through [(3)H]prazosin binding, and noradrenaline-induced intracellular Ca(2+) increases and contraction assays. Amitriptyline, nortriptyline and imipramine showed considerably higher affinities for alpha(1A)- (approximately 25- to 80-fold) and alpha(1D)-adrenoceptors (approximately 10- to 25-fold) than for alpha(1B)-adrenoceptors in both contraction and [(3)H]prazosin binding assays with rat native and human receptors, respectively. In addition, amitriptyline, nortriptyline and imipramine were substantially more potent in the inhibition of noradrenaline-induced intracellular Ca(2+) increases in HEK-293 cells expressing alpha(1A)- or a truncated version of alpha(1D)-adrenoceptors which traffics more efficiently towards the cell membrane than in cells expressing alpha(1B)-adrenoceptors. Amitriptyline, nortriptyline and imipramine are much weaker antagonists of rat and human alpha(1B)-adrenoceptors than of alpha(1A)- and alpha(1D)-adrenoceptors. The differential affinities for these receptors indicate that the alpha(1)-adrenoceptor subtype which activation is most increased by the augmented noradrenaline availability resultant from the blockade of neuronal reuptake is the alpha(1B)-adrenoceptor. This may be important for the behavioural effects of these drugs.
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Affiliation(s)
- F D Nojimoto
- Department of Pharmacology, Instituto de Biociências, UNESP, Botucatu, SP, Brazil
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Abstract
A simple, rapid and sensitive HPLC method was developed and validated for the determination of four tricyclic antidepressants (TCAs): amitriptyline, doxepin, clomipramine (CLO) and imipramine, in pharmaceutical formulations and biological fluids. A Kromasil C(8 )analytical column (250 x 4 mm, 5 microm) was used for the separation, with a mobile phase consisting of 0.05 M CH(3)COONH(4) and CH(3)CN (45:55 v/v) delivered at 1.5 mL/min isocratically. Quantification was performed at 238 nm, with bromazepam (1.5 ng/microL) as the internal standard. The determination of TCAs in blood plasma was performed after protein precipitation. Urine analysis was performed by means of SPE using Lichrolut RP-18 Merck cartridges providing high absolute recoveries (> 94%). Direct analysis of urine was also performed after two-fold dilution. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity. Repeatability (n = 5) and between-day precision (n = 5) revealed RSD <13%. Recoveries from biological samples ranged from 91.0 to 114.0%. The absolute detection limit of the method was calculated as 0.1-0.6 ng in blood plasma and 0.2-0.5 ng in extracted urine or 0.4-0.7 in diluted urine. The method was applied to real samples of plasma from a patient under CLO treatment.
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Affiliation(s)
- Victoria F Samanidou
- Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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Werling LL, Keller A, Frank JG, Nuwayhid SJ. A comparison of the binding profiles of dextromethorphan, memantine, fluoxetine and amitriptyline: Treatment of involuntary emotional expression disorder. Exp Neurol 2007; 207:248-57. [PMID: 17689532 DOI: 10.1016/j.expneurol.2007.06.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2007] [Revised: 06/15/2007] [Accepted: 06/20/2007] [Indexed: 10/23/2022]
Abstract
We compared the binding profiles of medications potentially useful in the treatment of involuntary emotional expression disorder at twenty-six binding sites in rat brain tissue membranes. Sites were chosen based on likelihood of being target sites for the mechanism of action of the agents in treating the disorder or their likelihood in producing side effects experienced by patients treated with psychoactive agents. We used radioligand binding assays employing the most selective labeled ligands available for sites of interest. Concentrations of labeled ligand were used at or below the K(i) value of the ligand for the target site. Compounds were initially screened at 1 muM. For compounds that competed for greater than 20-30% of specific binding at target sites of interest, full concentration curves were constructed. Dextromethorphan, amitriptyline and fluoxetine competed for binding to sigma(1) receptors and to serotonin transporters with high to moderate affinity. Of the target sites tested, these are the most likely to contribute to the therapeutic benefit of the various agents. In addition, all three drugs showed some activity at alpha(2) and 5-HT(1B/D) sites. Of the drugs tested, dextromethorphan bound to the fewest sites unlikely to be target sites. Although the mechanism of action of dextromethorphan or any drug that has been used in the treatment of involuntary emotional expression disorder is currently unknown, our data support that the affinity of the drug for sigma(1) receptors is consistent with its possible action through this receptor type in controlling symptoms of the disorder.
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Affiliation(s)
- Linda L Werling
- Department of Pharmacology and Physiology, The George Washington University Medical Center, Washington, DC 20037, USA.
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Abaut AY, Chevanne F, Le Corre P. Oral bioavailability and intestinal secretion of amitriptyline: Role of P-glycoprotein? Int J Pharm 2007; 330:121-8. [PMID: 17092666 DOI: 10.1016/j.ijpharm.2006.09.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2006] [Revised: 08/31/2006] [Accepted: 09/07/2006] [Indexed: 01/11/2023]
Abstract
The aim of the study was to evaluate the influence of quinidine, a P-glycoprotein inhibitor, on oral bioavailability and on intestinal secretion of amitriptyline, a tricyclic antidepressant. Amitriptyline was administrated intravenously (5 mg/kg) and orally (50 mg/kg) to rabbits, with and without quinidine. Jejunal segments of rats were mounted on diffusions chambers and the permeation of amitriptyline was measured across the tissue in luminal-serosal (LS) and serosal-luminal (SL) directions, with and without quinidine. Finally, an in situ recirculating intestinal perfusion model was performed in rabbits to study amitriptyline permeation in LS direction with and without quinidine. Absolute oral bioavailability (F) of amitriptyline was significantly increased more than three-fold in presence of quinidine (F = 0.6+/-0.4% versus 1.9+/-1.1%). The apparent permeability coefficients in SL direction were significantly higher than in LS direction (P(app (SL))=6.01+/-2.42 versus P(app (LS)) = 4.90+/-2.73 x 10(-4) cm min(-1)). In presence of quinidine, the intestinal absorption was increased (P(app (LS)) = 4.02+/-2.91 versus P(app (LS)) = 5.99+/-2.43 x 10(-4) cm min(-1)) and the intestinal secretion was decreased (P(app (SL)) = 4.58+/-0.54 versus P(app (LS)) = 3.63+/-1.46 x 10(-4) cm min(-1)) but not significantly. In conclusion, P-glycoprotein appears to be involved in oral amitriptyline absorption but other intestinal uptake and efflux transporters maybe implicated.
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Affiliation(s)
- Anne-Yvonne Abaut
- Unité UPRES EA 3892, Laboratoire de Pharmacie Galénique, Biopharmacie et Pharmacie Clinique, Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes 1, 2 avenue du Pr Léon Bernard, 35043 Rennes Cedex, France
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Pfuhlmann B, Gerlach M, Burger R, Gonska S, Unterecker S, Jabs B, Riederer P, Deckert J. Therapeutic drug monitoring of tricyclic antidepressants in everyday clinical practice. J Neural Transm Suppl 2007:287-296. [PMID: 17982905 DOI: 10.1007/978-3-211-73574-9_35] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Data about therapeutic drug monitoring (TDM) of psychotropic medications are often obtained from samples of highly selected individuals, who may not be representative for the average psychiatric patient. These data therefore may have limitations with regard to their transferability to everyday clinical practice. Therefore studies under naturalistic conditions are important to clarify the full clinical relevance of TDM. We retrospectively evaluated all TDM-analyses of the tricyclic antidepressants (TCA) amitriptyline and clomipramine during a 12-month period in an unselected sample of patients in a standard clinical setting. We especially examined the relationship between serum levels on one hand and clinical response and adverse effects on the other hand. In patients with amitriptyline, responders showed a significantly higher serum level than non-responders, whereas in patients with clomipramine a serum level within the recommended therapeutic range was associated with clinical response. We also found significantly higher serum concentrations in patients with adverse effects compared to patients without adverse effects in the clomipramine group. No such relationship could be shown in patients treated with amitriptyline. Our results suggest that therapeutic ranges in naturalistic settings in some ways differ from those obtained in controlled clinical settings and that TDM studies in everyday clinical practice are necessary and beneficial.
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Affiliation(s)
- B Pfuhlmann
- Department of Psychiatry and Psychotherapy, University of Würzburg, Würzburg, Germany.
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Uhr M, Grauer MT, Yassouridis A, Ebinger M. Blood-brain barrier penetration and pharmacokinetics of amitriptyline and its metabolites in p-glycoprotein (abcb1ab) knock-out mice and controls. J Psychiatr Res 2007; 41:179-88. [PMID: 16387324 DOI: 10.1016/j.jpsychires.2005.10.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2005] [Revised: 10/14/2005] [Accepted: 10/27/2005] [Indexed: 11/28/2022]
Abstract
In earlier studies with P-gp (abcb1) knock-out mice, we showed that P-gp exports the antidepressants citalopram, paroxetine, venlafaxine and amitriptyline and its metabolites across the blood-brain barrier, thereby reducing cerebral bioavailability of some substances up to 9 times. The present study investigated the pharmacokinetics of amitriptyline and whether abcb1ab double knock-out mice metabolize amitriptyline and its metabolites differently. P-gp knock-out mice and controls received a s.c. injection of 10mug amitriptyline/g of body weight. The animals were sacrificed after 30, 60, 120 and 240min and concentrations of amitriptyline and its metabolites were measured with HPLC in brain, plasma, liver, kidney, spleen, lung, muscle, fat and ovaries. Cerebral concentrations of amitriptyline and its metabolites were higher in P-gp-deficient mice compared to controls. No significant group effect was found for spleen, liver, lung, kidney and fat tissue. The results of our study indicate that amitriptyline and its metabolites are substrates of P-gp. Overall pharmacokinetics between knock-outs and controls were very similar. This confirms the validity of the P-gp knock-out model and allows for a continued research of the interactions between P-gp, the blood-brain barrier and CNS substances such as antidepressants, neuroleptics and others.
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Affiliation(s)
- Manfred Uhr
- Max Planck Institute of Psychiatry, Kraepelinstrasse 2-10, D-80804 Munich, Germany.
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Brecht S, Reiff J, Vock U, Voget J, Ley L, Boning A, Cremer J, Aldenhoff J, Herdegen T. Serum anticholinergic activity in patients following cardiac surgery and healthy individuals following amitriptyline application. ACTA ACUST UNITED AC 2007; 29:223-30. [PMID: 17520106 DOI: 10.1358/mf.2007.29.3.1075357] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The serum anticholinergic activity (SAA) is used as a marker for cognitive impairment. Here, two studies have been performed characterizing the SAA profile. In Study 1 the endogenous SAA in relation to the total serum protein concentration was monitored for 24 h in five healthy individuals and compared with that in four inpatients following cardiac surgery. In Study 2 the SAA of seven healthy individuals was assessed following a single amitriptyline dose. In both studies SAA was assessed by an ex vivo assay. In Study 1, the absolute SAA varied in a wide range of 1.2 and 14.5 atropine equivalents (AEs) over 24 h. A circadian pattern was not observed. The mean total serum protein concentration, but not the SAA, was significantly lower in inpatients than in healthy individuals. In Study 2, the SAA increased following amitriptyline to a maximum. The mean SAA increased by 6.39 AE at the amitriptyline peak concentration. High SAA variability showed a low statistical relation to amitriptyline concentrations. Both studies characterize the SAA as an individual parameter not affected per se by surgery or clinical care and poorly correlated with the total serum protein concentration. The relation with amitriptyline concentration helps to quantify SAA values towards a better understanding of the clinical implications and limitations of SAA changes.
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Affiliation(s)
- S Brecht
- Institute of Pharmacology, University Hospital of Schleswig-Holstein, Campus Kiel, Kiel, Germany
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16
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Shinya H, Hakoda S, Kinouchi S. [Plasma drug levels in amitriptyline overdose patient with complicated delayed cardiac arrhythmia and convulsions]. Chudoku Kenkyu 2006; 19:285-6. [PMID: 16922462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
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Manzo RH, Olivera ME, Amidon GL, Shah VP, Dressman JB, Barends DM. Biowaiver Monographs for Immediate Release Solid Oral Dosage Forms: Amitriptyline Hydrochloride**This paper reflects the scientific opinion of the authors and not the policies of regulating agencies. J Pharm Sci 2006; 95:966-73. [PMID: 16557529 DOI: 10.1002/jps.20615] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Literature data relevant to the decision to allow a waiver of in vivo bioequivalence (BE) testing for the approval of immediate release (IR) solid oral dosage forms containing amitriptyline hydrochloride are reviewed. Its therapeutic uses, its pharmacokinetic properties, the possibility of excipient interactions and reported BE/bioavailability (BA) problems are also taken into consideration. Literature data indicates that amitriptyline hydrochloride is a highly permeable active pharmaceutical ingredient (API). Data on the solubility according to the current Biopharmaceutics Classification System (BCS) were not fully available and consequently amitriptyline hydrochloride could not be definitively assigned to either BCS Class I or BCS Class II. But all evidence taken together, a biowaiver can currently be recommended provided that IR tablets are formulated with excipients used in existing approved products and that the dissolution meets the criteria defined in the Guidances.
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Affiliation(s)
- R H Manzo
- Pharmacy Department, Chemical Sciences Faculty, National University of Córdoba, Córdoba, Argentina
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18
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Abstract
We study the uptake of amitriptyline, which is a common cause of overdose-related fatalities, in aqueous solutions by 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) liposomes and liposomes composed of a mixture of DMPC and 1,2-dioleoyl-sn-glycero-3-[phospho-rac(1-glycerol)] (DOPG) lipids. The effect of drug concentration, liposomal charge, pH, salt, and protein presence on the drug uptake is investigated using two different methodologies, a precipitation and a centrifugation method. Furthermore, the time scale of the drug uptake is studied through qualitative observations at high pH and through conductivity measurements at neutral pH and found to be <5 s. The results of the quantitative studies show that the fractional drug uptake decreases with increasing drug concentration, and for a given concentration it increases with the pH and decreases in the presence of salt. We find that a larger amount of drug is sequestered by negatively charged liposomes (those containing DOPG) than liposomes with no net charge (DMPC). We speculate that the mechanism of drug uptake is due to both electrostatic interactions as well as hydrophobic effects. The fractional uptake by DMPC:DOPG in a 70:30 ratio is as high as 95% in water and about 90% in physiological buffer. The fractional uptake is also measured in presence of 2% (w/w) bovine serum albumin (BSA), which is approximately the protein concentration in the intercellular fluid. In presence of protein the fractional uptakes by 70:30 DMPC:DOPG liposomes and 50:50 DMPC:DOPG liposomes are 82 and 90%, respectively, at 125 muM drug amitriptyline. In the absence of liposomes, 67% of the drug is taken up by the protein in a 2% (w/w) BSA, 125 muM amitriptyline solution. Thus, addition of 50:50 DMPC:DOPG liposomes reduces the free drug concentration by a factor of about 3.5, making them attractive candidates for drug detoxification.
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Affiliation(s)
- Marissa S Fallon
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
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19
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Melkadze OO, Zurabashvili ZA. [Functional state of the dopaminergic system of the brain on a background of different doses of amitriptiline]. Georgian Med News 2006:91-3. [PMID: 16705240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The aim of the work is study of adsorbtion dynamics of amitriptiline on the surface of erythrocytes and to compare the obtained data with the character of pharmacokinetics and pharmacodynamics of amitriptiline in plasma. With the method of PLC the adsorb gas was been analyzed. The drag was administered to adult drugs and the blood sampled were collected following 10, 20, 60 min. and 4,0; 6,0 and 8,0 hours after the injection. In the supernatants from the erythrocytes and in the blood plasma the dopaminergic systems has been analyzed. Our data proved the ability of amitriptiline to adsorb on the surface of erythrocytes. Its concentration in the supernatant washed from the surface of erythrocytes and in the blood were not the same. It may be connected with the character and quantity of functional groups located on the surface of erythrocytes.
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Abstract
BACKGROUND Tricyclic antidepressant poisoning is often associated with significant cardiovascular and central nervous system toxicity. Effective treatment includes the use of appropriate gastric decontamination techniques, the administration of sodium bicarbonate, and meticulous supportive care. Tricylcic antidepressant toxicity typically lasts 24-48 hours following a significant overdose. CASE REPORT We describe a case of tricyclic antidepressant poisoning where significant clinical toxicity (QRS prolongation, metabolic acidosis) was observed for up to 4 days following ingestion of a modified-release preparation of amitriptyline. Successful patient recovery was associated with the use of multidose activated charcoal and repeated administration of intravenous sodium bicarbonate. CONCLUSIONS Clinicians should be aware of the potential for prolonged tricyclic toxicity in patients who have ingested modified-release amitriptyline in overdose. Gastric decontamination techniques such as multidose activated charcoal and whole bowel irrigation should be considered where there is evidence of ongoing tricyclic antidepressant absorption or clinical toxicity following ingestion of a modified-release preparation. These interventions may be indicated for prolonged periods (greater than 36 hours) post ingestion.
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Affiliation(s)
- Niall O'Connor
- Emergency Department, Guys and St. Thomas' NHS Trust, London, UK.
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21
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Castberg I, Helle J, Aamo TO. Association between plasma interleukin-18 levels and liver injury in chronic hepatitis C virus infection and non-alcoholic fatty liver disease. Ther Drug Monit 2006; 27:680-2. [PMID: 16175144 DOI: 10.1097/01.ftd.0000175910.68539.33] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
There is significant upregulation of interleukin-18 (IL-18) expression in viral infectious diseases and in some chronic hepatic diseases, especially (i) hepatitis C virus (HCV) infection, (ii) HCV infection with persistently normal ALT levels (PNAL), and (iii) non-alcoholic fatty liver disease (NAFLD). The aim of this study was a better understanding of the implications of plasma IL-18 levels in the above-mentioned liver diseases. Thirty-four patients with HCV infection, 13 with NAFLD, and 10 controls were enrolled. The HCV-RNA and HCV-genotypes and the serum or plasma levels of IL-18, aspartate aminotransferase (AST), alanine aminotransferase (ALT), gamma-glutamyltranspeptidase (gamma-GT), alkaline phosphatase, total cholesterol, triglycerides, alpha(1)-fetoprotein, and ferritin were evaluated. Patients with HCV showed higher levels of IL-18 than the NAFLD patients (p <0.01) and the controls (p <0.005). Patients with NAFLD showed higher values of body mass index and liver disease parameters, compared to HCV-infected subjects or controls. These data confirm previous reports of enhanced expression of IL-18 in patients with HCV and NAFLD, compared to healthy subjects, and suggest that IL-18 is important as a marker of liver diseases.
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Affiliation(s)
- Ingrid Castberg
- Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.
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22
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Skaggs SM, Foti RS, Fisher MB. A streamlined method to predict hepatic clearance using human liver microsomes in the presence of human plasma. J Pharmacol Toxicol Methods 2005; 53:284-90. [PMID: 16300971 DOI: 10.1016/j.vascn.2005.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 10/14/2005] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Human liver microsomal incubations are often used to predict the metabolic lability of new chemical entities. The clearance values are scaled-up from in vitro data and mathematically corrected for plasma protein binding, or in some cases the free fraction ratio of plasma to microsomes, using well-established scaling methods such as the well-stirred model. This can be time consuming for multiple compounds since it requires separate experiments to determine in vitro lability, and free fraction. METHODS We attempted to streamline clearance predictions by combining experiments into one. Firstly, we combined the free fraction experiments into one free fraction ratio by measuring the partitioning of compound between plasma and microsomes, and by applying this experimental ratio to clearance predictions found that it performed at least as well as free fractions determined separately. We also incubated compounds with plasma added to the incubation mixture and compared the predicted clearances to values determined using traditional mathematical protein binding corrections. RESULTS Consistently, incubations with added plasma resulted in CL predictions closer to literature values than incubations only mathematically corrected for protein binding. For example, incorporating plasma into a ketamine incubation resulted in a CL value of 15.1 mL/min/kg, compared with a value of 10.2 using mathematical binding corrections. The literature value is 16.4 mL/min/kg. DISCUSSION This work characterizes this new method and compares it to the traditional microsomal incubation method using several literature compounds, and suggests that streamlining the methods may generate quality data faster and with less resource investment.
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Affiliation(s)
- Sara M Skaggs
- Pfizer Global Research and Development, Pharmacokinetics, Dynamics, and Metabolism Pfizer, Inc. Groton, CT 06340, USA
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23
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Abstract
The cytochrome P450 enzymes (CYP) 2C19 and 2D6 are involved in the metabolism of many psychotropic drugs. Variability in enzyme activity results in variable metabolic capacities, affecting the metabolism of substrates. The metabolic ratio (MR) of drugs metabolized via these enzymes may therefore reflect the enzyme's activity and/or genotype. To serve as an example for different groups of medications, the selective serotonin reuptake inhibitor venlafaxine, the tricyclic antidepressant amitriptyline, and the antipsychotic risperidone were studied to examine a possible correlation between the MRs of these drugs and the CYP2C19 and/or CYP2D6 genotype. For this purpose data from routine genotyping and serum level analysis were used. The relationships between the observed metabolic ratios and CYP2D6 and/or CYP2C19 genotype were characterized using nonparametric statistical analysis. A clear correlation was observed between the CYP2D6 genotype and the metabolic ratio of venlafaxine. Genotyping of individuals with a log(MR) < -0.6 or a log(MR) > 0.2 would include all patients with an aberrant genotype but would result in a reduction of 52% of genotyping reactions. Slow metabolism of amitriptyline is correlated with a log(MR) > 0.4. Genotyping only those subjects with a log(MR) > 0.4 would result in 88% fewer genotyping reactions. For risperidone, genotyping individuals with a log(MR) > 0.4 would include all CYP2D6 poor metabolizers while reducing the number of genotyping reactions by 93%. According to these data, correlations exist between the log(MR) of venlafaxine, amitriptyline, and risperidone and the genotype of the CYP enzymes involved in their metabolism. From the ranges of log(MR) defined here, a high percentage of aberrant metabolizers can be detected even when patients are not routinely genotyped. Thus, the metabolic ratio may serve as an indication of when genotyping should be considered.
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Affiliation(s)
- Jan van der Weide
- Department of Clinical Chemistry, St Jansdal Hospital, Harderwijk, The Netherlands.
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Lee DW, Flint J, Morey T, Dennis D, Partch R, Baney R. Aromatic-aromatic interaction of amitriptyline: implication of overdosed drug detoxification. J Pharm Sci 2005; 94:373-81. [PMID: 15614810 DOI: 10.1002/jps.20256] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The objectives of this work are to explore the pi-pi complexation of amitriptyline with pi electron-deficient aromatic rings and demonstrate the feasibility of pi-pi complexation for overdosed drug detoxification. Water-soluble oligochitosan was chemically modified with dinitrobenzenesulfonyl groups to induce selective binding toward amitriptyline through pi-pi complexation. NMR studies showed that benzenesulfonyl and dinitrobenzenesulfonyl protons were upfield shifted by the addition of amitriptyline, indicating the formation of pi-pi complexes. The pi-pi complexation of amitriptyline is driven primarily by a desolvation driving force, whereas the magnitude of interaction is dictated by the complementrary electrostatic interaction. Isolated rat heart tests revealed that dinitrobenzenesulfonyl oligochitosan prevented the amitriptyline-induced cardiotoxicity and was itself not cardiotoxic.
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Affiliation(s)
- Dong-Won Lee
- Department of Materials Science and Engineering, Gainesville, Florida 32611, USA
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Abstract
Higher case fatality rates (CFR) were previously reported from desipramine than for 3 other tricyclic antidepressants (TCAs): amitriptyline, nortriptyline, and imipramine. The database of the American Association of Poison Control Centers (AAPCC) Toxic Exposure Surveillance System (TESS) for the 20 years 1983-2002 was used to evaluate the CFR of desipramine and the other TCAs. The CFR of desipramine was 2.25-, 2.31-, and 2.62-fold the CFR for amitriptyline, nortriptyline, and imipramine, respectively (P < 0.001). Mechanisms of desipramine toxicity and its dosage recommendations are discussed. Desipramine and nortriptyline have higher distribution volumes and erythrocyte/plasma ratios than their parent compounds imipramine and amitriptyline. This implies lower therapeutic plasma levels and reduced doses for desipramine and nortriptyline compared with their parent compounds. Such adjustments have been done for nortriptyline, but not for desipramine. The authors suggest that the high CFR of desipramine might be reduced by lowering its dose, therapeutic plasma level, and maximal pill content.
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Affiliation(s)
- Yona Amitai
- Department of Mother, Child and Adolescent Health, Ministry of Health, Jerusalem, Israel.
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27
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Grauer MT, Uhr M. P-glycoprotein reduces the ability of amitriptyline metabolites to cross the blood brain barrier in mice after a 10-day administration of amitriptyline. J Psychopharmacol 2004; 18:66-74. [PMID: 15107187 DOI: 10.1177/0269881104042831] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
P-glycoprotein (P-gp) is a 170-kDa membrane protein and the gene product of the multiple drug resistance (MDR1 or ABCB1) gene. It constitutes an important part of the blood-brain barrier and actively exports a number of molecules across the blood-brain barrier back into the vascular space, subsequently reducing central nervous system (CNS) bioavailability of these substances. The aim of the present study was to investigate the pharmacokinetics of amitriptyline and its metabolites in P-gp (also called mdr1ab or abcb1ab) knockout mice and controls after a long-term adminstration for 10 days. Knockout mice and controls received s.c. injections of amitriptyline (10 microg/g bodyweight) twice daily for 10 days. After 10 days, the animals were sacrificed and the concentrations of amitriptyline and nortriptyline and both their E-10-OH and Z-10-OH metabolites were measured with high-performance liquid chromatography in the cerebrum, plasma, spleen, kidney, testes, lung, liver, muscle and fat. Except for amitriptyline, the brain concentrations of all other examined substances were significantly higher in the P-gp knockout mice. Compared to controls, concentrations of nortriptyline were 2.6-fold higher, E-10-OH-nortriptyline 10-fold higher, Z-10-OH-nortriptyline seven-fold higher, E-10-OH-amitriptyline two-fold higher and Z-10-OH-amitriptyline five-fold higher. The present study confirms that P-gp plays an important role in the interaction between CNS drugs and the blood-brain barrier. Without P-gp at the blood-brain barrier, the brain concentrations of the substances were up to 10-fold higher, showing that P-gp plays an active role in exporting CNS drugs out of the brain. Recent clinical studies showing different side-effects in patients with P-gp polymorphisms confirm the clinical importance of these findings.
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Mealey KL, Peck KE, Bennett BS, Sellon RK, Swinney GR, Melzer K, Gokhale SA, Krone TM. Systemic absorption of amitriptyline and buspirone after oral and transdermal administration to healthy cats. J Vet Intern Med 2004; 18:43-6. [PMID: 14765730 DOI: 10.1892/0891-6640(2004)18<43:saoaab>2.0.co;2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A prospective study was performed to determine the relative availability of buspirone and amitriptyline after oral and transdermal routes of administration in 6 adult cats. For topical administration, drugs were compounded in a transdermal organogel containing pluronic and lecithin (PLO). Using a crossover design, each cat received a single dose of amitriptyline (5 mg) and buspirone (2.5 mg) by the transdermal and oral route of administration with at least a 2-week washout interval between drug treatments. Blood samples were obtained at 0, 0.5, 1, 2, 4, 6, 8, 10, and 12 hours after drug administration for determination of plasma drug concentrations. Plasma concentrations of immunoreactive amitriptyline and buspirone were determined using commercial enzyme-linked immunosorbent assay (ELISA) tests. Systemic absorption of amitriptyline and buspirone administered by the transdermal route was poor compared with the oral route of administration. Until supporting pharmacokinetic data are available, veterinarians and cat owners should not rely on the transdermal route of administration for treating cats with amitriptyline or buspirone.
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Affiliation(s)
- K L Mealey
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-6610, USA.
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Strümper D, Durieux ME. Topical antidepressants: the new local anesthetics? Reg Anesth Pain Med 2003; 28:268-70. [PMID: 12945018 DOI: 10.1016/s1098-7339(03)00194-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
The aim of the present study was to investigate the effects of fatty acids on the permeation of tricyclic antidepressants, e.g., imipramine hydrochloride (IMH) and amitriptyline hydrochloride (AMH). Five percent w/v of saturated (lauric acid) and unsaturated (oleic acid, linoleic acid, linolenic acid, trans-elaidic acid and trans-vaccenic acid) fatty acids in an ethanol (EtOH):water (2:1) system were used in this study. Flux and lag-time of tricyclic antidepressants were significantly increased and reduced, respectively, compared with control (p < 0.05). There were no significant differences between the effects of lauric and unsaturated fatty acids, both cis and trans, on the permeation of IMH and AMH (except vaccenic acid in case of IMH). The formation of 'grain boundaries' by straight chain fatty acids (saturated and trans-unsaturated fatty acids) could not be observed by Fourier-transform infrared spectroscopy (FT-IR). However, perturbation or increased bilayer fluidity of Stratum corneum (SC) induced by cis-unsaturated fatty acid was observed by FT-IR.
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Affiliation(s)
- A K Jain
- Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER), Mohali, India
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Franssen EJF, Kunst PWA, Bet PM, Strack van Schijndel RJM, van Loenen AC, Wilhelm AJ. Toxicokinetics of nortriptyline and amitriptyline: two case reports. Ther Drug Monit 2003; 25:248-51. [PMID: 12657923 DOI: 10.1097/00007691-200304000-00018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Two cases are presented of intentional intoxications with the tricyclic antidepressants (TCAs) nortriptyline (NT) and amitriptyline (AT). The peak plasma concentrations were 2290 microg/L and 2900 microg/L, respectively. The active metabolites E-10-hydroxynortriptyline (EHNT) and Z-10-hydroxynortriptyline (ZHNT) profiles were quite different as monitored for 5 to 10 days after presumed drug intake. In conclusion, these cases illustrate that (1) metabolite formation and elimination after intake of an overdose dose of NT and AT are stereoselective, and (2) NT and EHNT toxicokinetics and toxicodynamics are quite different. It also shows that a patient with a severe TCA overdose can still survive if he or she receives appropriate and quick supportive care, even if the prognostic markers QRS time, coma grade, and serum TCA levels predict poor outcome.
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Affiliation(s)
- E J F Franssen
- Department of Pharmacy, University Hospital, Vrije Universiteit, Amsterdam, The Netherlands.
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Abstract
OBJECTIVE To assess the steady-state pharmacokinetics of mirtazapine (30 mg/day orally) and amitriptyline (75 mg/day orally) during combined administration compared with that of either drug administered alone. To evaluate the tolerability and effects on psychometric tests of acute and subchronic administration of both drugs combined and alone. METHODS In a single-blind, three-way cross-over study, 24 (12 male and 12 female) healthy subjects were randomly assigned to six different sequences of three 9-day treatments, i.e. racemic mirtazapine (30 mg/day), amitriptyline (75 mg/day) or the combination of these drugs. To control for acute pharmacodynamic assessments, during the first treatment period, a placebo group (n = 8; 4 females and 4 males) was added. Serial blood samples were drawn for plasma level measurements that were subsequently subjected to pharmacokinetic analysis. Psychometric tests assessed attentional performance, and a computer-assisted telephone questionnaire assessed self-ratings of drowsiness/alertness and sleep quality. RESULTS Amitriptyline increased the C(max) of mirtazapine (+ 36%, p < 0.05) in male subjects only. Mirtazapine altered the C(max) of amitriptyline in both male (+ 23%, p < 0.05) and female (- 23%, p < 0.05) subjects. No changes were observed for other pharmacokinetic parameters. Metabolite parameters were not affected. Changes in parent compound levels mainly resulted from effects on absorption. The psychometric test results did not reveal significant changes between combined and single drug treatments. The telephone registrations of VAMRS and LSEQ did not show clinically relevant differences between the active treatments. CONCLUSION Combined administration of mirtazapine (30 mg/day) and amitriptyline (75 mg/day) alters the pharmacokinetics of either compound to a minor extent. Adding one drug to the other and substituting one drug by the other had no major effects on tolerability. Nevertheless, caution is warranted when combining amitriptyline and mirtazapine.
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Affiliation(s)
- C Sennef
- NV Organon, PO Box 20, 5340 BH Oss, The Netherlands
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Razaghi AM, Schwartz JB. Investigation of cyclobenzaprine hydrochloride release from oral osmotic delivery systems containing a water-swellable polymer. Drug Dev Ind Pharm 2002; 28:631-9. [PMID: 12149955 DOI: 10.1081/ddc-120003854] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Oral osmotic delivery systems containing polyethylene oxide (PEO, a water-swellable polymer) were designed and the release of cyclobenzaprine hydrochloride (model drug) from the devices was investigated. The systems consisted of model drug, mannitol (osmotic agent), and increasing amounts of PEO surrounded by a semipermeable membrane drilled with a delivery orifice. There was a decrease in drug release rate with PEO in the core. This may be due to solubility-modulating properties of the polymer. Visual inspection of the devices with PEO showed significant swelling during dissolution testing. Swelling (internal pressure) may influence water inhibition rate into the core and subsequently drug release rate. The release rates were a function of membrane thickness. The release rates were independent of orifice size (range of 150-510 microns diameter) and hydrodynamic conditions for the devices. This would be advantageous in the delivery of drugs in man.
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Affiliation(s)
- Amir M Razaghi
- Schering-Plough Technical Operations, 1011 Morris Ave., U-13 Trailer, Union, NJ 07083, USA.
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Jiang ZP, Shu Y, Chen XP, Huang SL, Zhu RH, Wang W, He N, Zhou HH. The role of CYP2C19 in amitriptyline N-demethylation in Chinese subjects. Eur J Clin Pharmacol 2002; 58:109-13. [PMID: 12012142 DOI: 10.1007/s00228-002-0445-6] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2001] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To determine the role of cytochrome P(450) (CYP)2C19 in N-demethylation of amitriptyline (AT) in healthy Chinese subjects. METHODS One hundred and one subjects were genotyped for CYP2C19 using polymerase chain reaction-restriction fragment length polymorphism analysis. Twelve unrelated adult men (19.7+/-0.6 years, 61.8+/-3.8 kg) were chosen and orally given a single dose of 50 mg AT, and the blood samples were drawn from a forearm vein at 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 24, 48, 72, and 96 h after AT administration. Plasma concentrations of AT and nortriptyline (NT) were determined using high-performance liquid chromatography with an ultraviolet detector. RESULTS The mean area under the plasma concentration-time curve (AUC(AT)) of CYP2C19 poor metabolizers (PMs, n=6) was significantly higher than that of CYP2C19 extensive metabolizers (EMs, n=6) (2207+/-501 ng/ml x h(-1) vs 1596+/-406 ng/ml x h(-1), P<0.05). In contrast, the mean AUC(NT(0-)(infinity)()) of PMs was significantly lower than that of EMs (294+/-70 ng/ml x h(-1) vs 684+/-130 ng/ml x h(-1), P<0.0001). Other pharmacokinetic parameters such as clearance, half-life, maximum plasma concentration, and time to peak plasma concentration showed no significant difference between PMs and EMs (0.41+/-0.12 l /h x kg(-1) vs 0.50+/-0.15 l /h x kg(-1), 25.0+/-6.2 h vs 24.1+/-4.4 h, 96+/-25 ng/ml vs 75+/-27 ng/ml, 4.0+/-1.4 h vs 3.7+/-1.5 h, respectively). CONCLUSION The genetic defects of CYP2C19 have a significant effect on AT pharmacokinetics, and CYP2C19 plays an important role in N-demethylation of AT in vivo at a clinically therapeutic dose.
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Affiliation(s)
- Zhi-Ping Jiang
- Pharmacogenetics Research Institute, Xiang-Ya School of Medicine, Central South University, Changsha 410078, China
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Johne A, Schmider J, Brockmöller J, Stadelmann AM, Störmer E, Bauer S, Scholler G, Langheinrich M, Roots I. Decreased plasma levels of amitriptyline and its metabolites on comedication with an extract from St. John's wort ( Hypericum perforatum ). J Clin Psychopharmacol 2002; 22:46-54. [PMID: 11799342 DOI: 10.1097/00004714-200202000-00008] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Extracts of St. John's wort ( Hypericum perforatum ) became increasingly popular as easily available remedies for mild to moderate depression. Comedication with hypericum extract was recently shown to drastically reduce plasma concentration of ciclosporin, digoxin, and indinavir. We investigated the possible interaction of hypericum extract LI160 with amitriptyline. Both antidepressants have a high probability of concomitant use. Twelve patients requiring amitriptyline treatment received a single dose of hypericum extract (900 mg) at day 1, continued by a 12-to 14-day treatment with retarded amitriptyline (75 mg twice daily). Then hypericum (900 mg/day) was added for another 14 to 16 days. Steady-state pharmacokinetics of amitriptyline were compared before and after multiple-dose treatment with hypericum extract. Furthermore, comparisons were made for single-dose kinetics of hypericum-extract ingredients hypericin, pseudohypericin, and hyperforin between the first day of concomitant treatment and LI160 alone. Multiple-dose comedication with LI160 led to a statistically significant decrease in the area under the plasma concentration-time curve within one dosing interval of amitriptyline by 22% ( p = 0.03) and nortriptyline by 41% ( p = 0.002), as well as of all hydroxylated metabolites, except for 10-E-hydroxynortriptyline. Plasma levels of amitriptyline and hydroxylated metabolites gradually decreased, whereas nortriptyline concentrations were already markedly decreased after 3 days of cotreatment with hypericum. Cumulative urinary amounts of amitriptyline and metabolites decreased to the same extent as plasma concentrations upon hypericum comedication. Induction of cytochrome P-450 enzymes or drug transporters (P-glycoprotein) by St. John's wort extract may explain this pharmacokinetic interaction. Physicians should be aware of this interaction when treating patients with amitriptyline.
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Affiliation(s)
- Andreas Johne
- Institute of Clinical Pharmacology, University Medical Center Charité, Humboldt University of Berlin, Berlin, Germany
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Winchell GA, King JD, Chavez-Eng CM, Constanzer ML, Korn SH. Cyclobenzaprine pharmacokinetics, including the effects of age, gender, and hepatic insufficiency. J Clin Pharmacol 2002; 42:61-9. [PMID: 11808825 DOI: 10.1177/0091270002042001007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The pharmacokinetics and bioavailability of cyclobenzaprine, a widely used muscle relaxant, were investigated in four clinical studies, and the effects of age, gender, and hepatic insufficiency were characterized. Cyclobenzaprine plasma clearance was 689 ml/min, and the bioavailability of a 5 mg oral dose was 0.55. Following oral doses of 2.5 to 10 mg tid in healthy young subjects, cyclobenzaprine pharmacokinetics were linear, and plasma concentrations generally increased proportional to dose. There was about a fourfold accumulation of the drug in plasma on multiple dosing, corresponding to an effective half-life of 18 hours. Steady-state plasma concentrations of cyclobenzaprine in elderly subjects were twice as high as in young subjects following oral doses of 5 mg tid. Steady-state plasma concentration also appeared to be up to twofold higher in subjects with mild hepatic insufficiency compared to healthy controls. The magnitude of any difference in steady-state plasma concentration between males and females appears to be small relative to intersubject variability. A reduction in dose or dosing frequency should be considered in the elderly and in patients with liver disease.
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Abstract
BACKGROUND Amitriptyline has been reported to be a more potent local anesthetic than bupivacaine. In keeping with the objective of identifying drugs for prolonged cutaneous analgesia, the authors compared the cutaneous analgesic effectiveness of amitriptyline and bupivacaine in rats. METHODS Rats were subcutaneously injected on shaved dorsal skin. The skin wheal raised after injection of 0.6 ml of various concentrations of either amitriptyline or bupivacaine with and without epinephrine (1:200,000) was marked. Inhibition of the cutaneous trunci muscle reflex was evaluated quantitatively by the fraction of times a total of six pinpricks applied to the marked area failed to elicit a nocifensive motor response compared with control responses. No responses out of six pinpricks was defined as 100% maximum possible effect. RESULTS Complete recovery from the cutaneous analgesia elicited by 0.05% and 0.5 amitriptyline versus 0.05 and 0.5% bupivacaine occurred in 9.9 +/- 0.2 and 19.3 +/- 0.4 h versus 2.2 +/- 0.1 and 16.1 +/- 0.2 h, respectively (mean +/- SE). Addition of epinephrine increased this duration to 14.1 +/- 0.1 and 21.4 +/- 0.2 h versus 3.2 +/- 0.1 and 17.0 +/- 0.3 h, respectively. Complete nociceptive blockade after coinjection of 0.25% amitriptyline, 0.25% bupivacaine, and epinephrine lasted 24 +/- 0.5 h, and complete recovery from this block took 33 +/- 0.5 h. Areas under the percent maximum possible effect versus time curve were 1,770 +/- 24 and 1,471 +/- 50% h for 0.5% amitriptyline and bupivacaine with epinephrine, respectively, whereas this value was 2,836 +/- 62% h for the coinjected 0.25% amitriptyline, 0.25% bupivacaine, and epinephrine admixture. CONCLUSION Amitriptyline is a longer-acting local anesthetic compared with bupivacaine for cutaneous infiltration. Its analgesic effectiveness is significantly enhanced by epinephrine. Coinjection of amitriptyline and bupivacaine with epinephrine enhances the analgesic duration of both drugs.
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Affiliation(s)
- Mohammed A Khan
- Department of Anesthesiology, Perioperative and Pain Medicne, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
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Daniel WA, Wójcikowski J, Pałucha A. Intracellular distribution of psychotropic drugs in the grey and white matter of the brain: the role of lysosomal trapping. Br J Pharmacol 2001; 134:807-14. [PMID: 11606321 PMCID: PMC1573011 DOI: 10.1038/sj.bjp.0704319] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Since the brain is not a homogenous organ (i.e. the phospholipid pattern and density of lysosomes may vary in its different regions), in the present study we examined the uptake of psychotropic drugs by vertically cut slices of whole brain, grey (cerebral cortex) and white (corpus callosum, internal capsule) matter of the brain and by neuronal and astroglial cell cultures. 2. Moreover, we assessed the contribution of lysosomal trapping to total drug uptake (total uptake=lysosomal trapping+phospholipid binding) by tissue slices or cells conducting experiments in the presence and absence of 'lysosomal inhibitors', i.e., the lysosomotropic compound ammonium chloride (20 mM) or the Na(+)/H(+)-ionophore monensin (10 microM), which elevated the internal pH of lysosomes. The initial concentration of psychotropic drug in the incubation medium was 5 microM. 3. Both total uptake and lysosomal trapping of the antidepressants investigated (imipramine, amitriptyline, fluoxetine, sertraline) and neuroleptics (promazine, perazine, thioridazine) were higher in the grey matter and neurones than in the white matter and astrocytes, respectively. Lysosomal trapping of the psychotropics occurred mainly in neurones where thioridazine sertraline and perazine showed the highest degree of lysosomotropism. 4. Distribution interactions between antidepressants and neuroleptics took place in neurones via mutual inhibition of lysosomal trapping of drugs. 5. A differential number of neuronal and glial cells in the brain may mask the lysosomal trapping and the distribution interactions of less potent lysosomotropic drugs in vertically cut brain slices. 6. A reduction (via a distribution interaction) in the concentration of psychotropics in lysosomes (depot), which leads to an increase in their level in membranes and tissue fluids, may intensify the pharmacological action of the combined drugs.
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Affiliation(s)
- W A Daniel
- Polish Academy of Sciences, Institute of Pharmacology, Smetna 12, 31-343 Kraków, Poland.
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Venkatakrishnan K, Schmider J, Harmatz JS, Ehrenberg BL, von Moltke LL, Graf JA, Mertzanis P, Corbett KE, Rodriguez MC, Shader RI, Greenblatt DJ. Relative contribution of CYP3A to amitriptyline clearance in humans: in vitro and in vivo studies. J Clin Pharmacol 2001; 41:1043-54. [PMID: 11583471 DOI: 10.1177/00912700122012634] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The relative contribution of cytochrome P450 3A (CYP3A) to the oral clearance of amitriptyline in humans has been assessed using a combination of in vitro approaches together with a clinical pharmacokinetic interaction study using the CYP3A-selective inhibitor ketoconazole. Lymphoblast-expressed CYPs were used to study amitriptyline N-demethylation and E-10 hydroxylation in vitro. The relative activity factor (RAF) approach was used to predict the relative contribution of each CYP isoform to the net hepatic intrinsic clearance (sum of N-demethylation and E-10 hydroxylation). Assuming no extrahepatic metabolism, the model-predicted contribution of CYP3A to net intrinsic clearance should equal the fractional decrement in apparent oral clearance of amitriptyline upon complete inhibition of the enzyme. This hypothesis was tested in a clinical study of amitriptyline (50 mg, p.o.) with ketoconazole (three 200 mg doses spaced 12 hours apart) in 8 healthy volunteers. The RAF approach predicted CYP2C19 to be the dominant contributor (34%), with a mean 21% contribution of CYP3A (range: 8%-42% in a panel of 12 human livers). The mean apparent oral clearance of amitriptyline in 8 human volunteers was decreased from 2791 ml/min in the control condition to 2069 ml/min with ketoconazole. The average 21% decrement (range: 2%-40%) was identical to the mean value predicted in vitro using the RAF approach. The central nervous system (CNS) sedative effects of amitriptyline were slightly greater when ketoconazole was coadministered, but the differences were not statistically significant. In conclusion, CYP3A plays a relatively minor role in amitriptyline clearance in vivo, which is consistent with in vitro predictions using the RAF approach.
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Affiliation(s)
- K Venkatakrishnan
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine and New England Medical Center, Boston, MA 02111, USA
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Venkatakrishnan K, von Moltke LL, Greenblatt DJ. Application of the relative activity factor approach in scaling from heterologously expressed cytochromes p450 to human liver microsomes: studies on amitriptyline as a model substrate. J Pharmacol Exp Ther 2001; 297:326-37. [PMID: 11259560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
The relative activity factor (RAF) approach is being increasingly used in the quantitative phenotyping of multienzyme drug biotransformations. Using lymphoblast-expressed cytochromes P450 (CYPs) and the tricyclic antidepressant amitriptyline as a model substrate, we have tested the hypothesis that the human liver microsomal rates of a biotransformation mediated by multiple CYP isoforms can be mathematically reconstructed from the rates of the biotransformation catalyzed by individual recombinant CYPs using the RAF approach, and that the RAF approach can be used for the in vitro-in vivo scaling of pharmacokinetic clearance from in vitro intrinsic clearance measurements in heterologous expression systems. In addition, we have compared the results of two widely used methods of quantitative reaction phenotyping, namely, chemical inhibition studies and the prediction of relative contributions of individual CYP isoforms using the RAF approach. For the pathways of N-demethylation (mediated by CYPs 1A2, 2B6, 2C8, 2C9, 2C19, 2D6, and 3A4) and E-10 hydroxylation (mediated by CYPs 2B6, 2D6, and 3A4), the model-predicted biotransformation rates in microsomes from a panel of 12 human livers determined from enzyme kinetic parameters of the recombinant CYPs were similar to, and correlated with the observed rates. The model-predicted clearance via N-demethylation was 53% lower than the previously reported in vivo pharmacokinetic estimates. Model-predicted relative contributions of individual CYP isoforms to the net biotransformation rate were similar to, and correlated with the fractional decrement in human liver microsomal reaction rates by chemical inhibitors of the respective CYPs, provided the chemical inhibitors used were specific to their target CYP isoforms.
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Affiliation(s)
- K Venkatakrishnan
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA
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Abstract
RATIONALE Although tricyclic antidepressants (TCAs) have gained wide acceptance for use in the treatment of depression in pregnant women, their pharmacokinetics during pregnancy have been poorly characterized. The aim of the present study was to investigate the transplacental transfer of amitriptyline (AMI) and its main active metabolite nortriptyline (NOR) in isolated perfused human placenta. METHODS Nine term human placentae were obtained immediately after delivery with maternal consent and a 2-h non-recirculating perfusion of a single placental cotyledon was performed. AMI (200 ng/ml) and NOR (150 ng/ml), with antipyrine as a reference compound, were added to the maternal reservoir and their appearance to the fetal circulation was followed for 2 h. AMI and NOR concentrations were measured by high performance liquid chromatography (HPLC) and antipyrine concentrations spectrophotometrically. RESULTS The mean (SD) transplacental transfers (TPT(SS)%) for AMI and NOR were 8.2 (2.3)% and 6.5 (1.8)%, respectively, calculated as the ratio between the steady-state concentrations in fetal venous and maternal arterial sides. The TPTs of AMI and NOR were 81% and 62% of the freely diffusable antipyrine. The absolute fraction of the dose that crossed the placenta (TPT(A)) was moderately, but significantly higher for AMI (7.7%) than for NOR (5.7%) (P=0.037). In all perfusions, steady state at the fetal side was reached by 30 min for AMI and by 50 min for NOR in the fetal side. The viability of the placentae was retained during the 2-h perfusion, as evidenced by unchanged pH of the perfusate and by stable perfusion pressures in fetal artery and stable antipyrine transfer. CONCLUSIONS Both AMI and NOR cross the human placenta. However, the fetal exposure with NOR may be somewhat smaller compared with AMI, probably due to the higher lipophilicity of AMI.
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Affiliation(s)
- T Heikkinen
- Department of Pharmacology and Clinical Pharmacology, University of Turku, Finland.
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42
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Amann B, Grunze H, Hoffmann J, Schäfer M, Kuss HJ. [Non-fatal effect of highly toxic amitriptyline level after suicide attempt. A case report]. Nervenarzt 2001; 72:52-5. [PMID: 11221556 DOI: 10.1007/s001150050711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Pharmacotherapeutic intervention in psychiatric patients often bears the risk of drug abuse for suicide attempts. Especially intoxication with tricyclic antidepressants, e.g., amitriptyline, may cause severe complications such as cardiac arrhythmia. Even under intensive care conditions, 2-3% of intoxicated patients still die. Here, we report on a depressed female patient who, thanks to timely and intense intervention, survived a suicide attempt with amitriptyline despite highly toxic plasma levels.
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Affiliation(s)
- B Amann
- Psychiatrische Klinik der Universität München
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Abstract
The air-water partition coefficients, K(aw), highly correlated with the corresponding lipid-water partition coefficients, K(lw), and the critical micelle concentrations, CMC, were measured for 11 compounds for which the kinetic parameters of P-glycoprotein ATPase activation (Michaelis-Menten constant, K(m), and maximal velocity, V(max)) had been determined previously in inside-out vesicles of CR1R12 Chinese hamster ovary cells. In addition, the hydrogen bond donor patterns (type I and type II) relevant for substrate recognition by P-glycoprotein were determined from the energy-minimized three-dimensional structure of these compounds. A linear relation between the air-water partition coefficient, K(aw), and the inverse of the Michaelis-Menten constant, K(m), was observed such that K(m) x K(aw) approximately = 1. The maximal velocity, V(max), was shown to decrease with the number and strength of electron donor (hydrogen bond acceptor) groups in recognition patterns. If two substrates are applied simultaneously to P-glycoprotein the compound with the higher potential to form hydrogen bonds generally acts as an inhibitor. We conclude that partitioning into the lipid membrane is the rate-limiting step for the interaction of a substrate with P-glycoprotein and that dissociation of the P-glycoprotein-substrate complex is determined by the number and strength of the hydrogen bonds formed between the substrate and the transporter.
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Affiliation(s)
- A Seelig
- Department of Biophysical Chemistry, Biocenter, University of Basel, Klingelbergstrasse 70, Basel, Switzerland.
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Baeck SK, Lim MA, Park SY, Lee JS, Lee HS, Koo KS. Blood concentrations of amitriptyline and its metabolite in rats after acute oral administration of amitriptyline. J Anal Toxicol 2000; 24:271-4. [PMID: 10872574 DOI: 10.1093/jat/24.4.271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Amitriptyline (AMT), a tricyclic antidepressant that is a dibenzocycloheptadine derivative, is frequently used. However, the case reports of AMT-related fatalities are increased, nowadays, due to the low levels of toxic and fatal concentration in blood. So, this study was carried out to determine the concentrations of AMT and its demethylated metabolite, nortriptyline (NTR), after acute single oral administration of AMT in rats. Blood samples were collected five times from the ophthalmic venous plexus at 0, 1, 2, 4, and 8 h after acute single oral administration of AMT in toxic doses of 10 (Group I) or 20 mg/kg (Group II), and the concentrations of AMT and NTR and the mean ratios of AMT to NTR (AMT/NTR) in the blood were periodically determined at designated times. The blood concentrations of AMT and NTR were identified and quantitated by gas chromatography with thermionic specific detection and gas chromatography-mass spectrometry after solid-phase extraction with a Clean Screen DAU column. The peak blood concentrations of AMT and NTR in Group I were 0.34 and 0.28 microg/mL, respectively, and those of AMT and NTR in Group II were 0.59 and 0.43 microg/mL, respectively, and were reached at 1 h after single oral administration.
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Affiliation(s)
- S K Baeck
- Forensic Science Department, National Institute of Scientific Investigation, Seoul, Korea
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Uhr M, Steckler T, Yassouridis A, Holsboer F. Penetration of amitriptyline, but not of fluoxetine, into brain is enhanced in mice with blood-brain barrier deficiency due to mdr1a P-glycoprotein gene disruption. Neuropsychopharmacology 2000; 22:380-7. [PMID: 10700657 DOI: 10.1016/s0893-133x(99)00095-0] [Citation(s) in RCA: 173] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Mice with a genetic disruption (knockout) of the multiple drug resistance (Mdr1a) gene were used to examine the effect of the absence of the drug-transporting P-glycoprotein at the blood-brain barrier on the uptake of amitriptyline (AMI) and fluoxetine (FLU) and their metabolites into the brain. One hour after intraperitoneal injection of AMI or FLU, knockout (-/-) and wild-type (+/+) mice were sacrificed and drug concentrations of brain, kidney, liver, testis, and plasma were measured. The plasma concentrations of the AMI metabolites and the brain:spleen ratios of AMI, nortriptyline (NOR), 10-OH-AMI and 10-OH-NOR were significantly higher in the -/- mice, demonstrating that AMI and its metabolites are substrates of the P-glycoprotein and that mdr1a activity at the level of the blood-brain barrier reduces the penetration of these substances into the brain. In contrast, tissue distributions of FLU and its metabolites among the various tissues tested were indistinguishable between groups. The herein reported differences in brain penetration of antidepressant drugs depending on the presence of the mdr1a gene may offer an explanation for differences in the treatment response at a given plasma concentration. Moreover, individual differences in mdr1 gene activity may account for variable response patterns at different episodes and development of therapy resistance.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B/genetics
- ATP Binding Cassette Transporter, Subfamily B/metabolism
- ATP Binding Cassette Transporter, Subfamily B, Member 1/deficiency
- ATP Binding Cassette Transporter, Subfamily B, Member 1/drug effects
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Amitriptyline/pharmacokinetics
- Animals
- Antidepressive Agents, Second-Generation/pharmacokinetics
- Antidepressive Agents, Tricyclic/pharmacokinetics
- Blood-Brain Barrier/drug effects
- Brain/drug effects
- Chromatography, High Pressure Liquid
- Fluoxetine/pharmacokinetics
- Male
- Mice
- Mice, Knockout
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Affiliation(s)
- M Uhr
- Max Planck Institute of Psychiatry, Munich, Germany
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Abstract
Oral drug therapy in patients with short bowel syndrome can be quite challenging. We report the case of a 40-yr-old woman with short bowel syndrome and depression requiring antidepressant drug therapy. After buccal administration of amitriptyline, therapeutic serum antidepressant concentrations were attained despite the patient having only 18 inches of proximal small bowel. Clinical improvement in mood was seen, with the only drug side effects being dry mouth and bitter drug taste. Buccal absorption likely is playing a major role in attaining therapeutic serum tricyclic antidepressants drug concentrations.
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Affiliation(s)
- B Robbins
- Department of Medicine, University of Rochester School of Medicine and Dentistry, New York 14621-3095, USA
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Abstract
The purpose of the present study was to investigate the contribution of lysosomal trapping to the total tissue uptake of thioridazine and to potential drug distribution interactions between thioridazine and tricyclic antidepressants (imipramine, amitriptyline) or selective serotonin reuptake inhibitors (SSRIs; fluoxetine, sertraline). The experiment was carried out on slices of various rat tissues as a system with intact lysosomes. Thioridazine and antidepressants (5 microM) were incubated separately or jointly with the tissue slices in the absence or presence of "lysosomal inhibitors," i.e., ammonium chloride or monensin. The results show that the contribution of lysosomal trapping to the total tissue uptake of thioridazine is as important as phospholipid binding. A high degree of dependence of thioridazine tissue uptake on the lysosomal trapping is the cause of substantial distributive interactions between thioridazine and the investigated antidepressants at the level of cellular distribution. Thioridazine and the antidepressants, both tricyclic and SSRIs, mutually decreased their tissue uptake. The potency of antidepressants to decrease thioridazine uptake was similar to that of lysosomal inhibitors. In general, the observed interactions between thioridazine and antidepressants occurred only in those tissues in which thioridazine showed lysosomotropism (the lungs, liver, kidneys, brain, and muscles) but were not observed in the presence of ammonium chloride. The above finding provides evidence that the interactions proceeded at the level of lysosomal trapping. In the adipose tissue and heart no lysosomal trapping of thioridazine was detected and those tissues were not the site of such an interaction. Since the organs and tissues involved in the distributive interactions constitute a major part of the organism and take up most of the total drug in the body, the interactions occurring in them may cause a substantial shift of the drugs to organs and tissues poor in lysosomes, e.g. the heart and muscles. An in vivo study into the thioridazine-imipramine interaction showed that joint administration of the drugs under study (10 mg/kg ip) increased drug concentration ratios of lysosome-poor tissue/plasma and lysosome-poor/lysosome-rich tissue. Considering serious side effects of thioridazine and tricyclic antidepressants (cardiotoxicity, anticholinergic activity), the thioridazine-antidepressant combinations studied should be approached with respect to the appropriate dose adjustment.
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Affiliation(s)
- W A Daniel
- Polish Academy of Sciences, Institute of Pharmacology, Smetna 12, Kraków, 31-343, Poland
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Abstract
AIMS To characterize the pharmacokinetics of amitriptyline and its metabolite nortriptyline following OROS and IR treatments, and to correlate them with anticholinergic side-effects. METHODS The pharmacokinetics and safety of amitriptyline following administration of an osmotic controlled release tablet (OROS and an immediate release (IR) tablet were evaluated in 14 healthy subjects. In this randomized, open label, three-way crossover feasibility study, the subjects received a single 75 mg OROS tablet, three 25 mg IR tablets administered every 8 h, or 3x25 mg IR tablets administered at nighttime. In each treatment arm serial blood samples were collected for a period of 84 h after dosing. The plasma samples were analysed by gas chromatography for amitriptyline and its metabolite nortriptyline. Anticholinergic effects such as saliva output, visual acuity, and subject-rated drowsiness and dry mouth were measured on a continuous scale during each treatment period. RESULTS Following dosing with OROS (amitriptyline hydrochloride), the mean maximal plasma amitriptyline concentration Cmax (15.3 ng ml-1 ) was lower and the mean tmax (25.7 h) was longer than that associated with the equivalent IR dose administered at nighttime (26.8 ng ml-1 and 6.3 h, respectively). The bioavailability of amitriptyline following OROS dosing was 95% relative to IR every 8 h dosing, and 89% relative to IR nighttime dosing. The metabolite-to-drug ratios after the three treatment periods were similar, suggesting no change in metabolism between treatments. The relationships between plasma amitriptyline concentration and anticholinergic effects (e.g. reduced saliva weight, dry mouth, and drowsiness) were similar with all three treatments. Of the anticholinergic effects, only decreased saliva weight and dry mouth correlated well with plasma amitriptyline concentrations; drowsiness did not. There was no apparent correlation between anticholinergic effects and the plasma nortriptyline concentration. CONCLUSIONS The bioavailability of OROS (amitriptyline hydrochloride) was similar to that of the IR treatments and the pharmacokinetics of amitriptyline after OROS dosing may decrease the incidence of anticholinergic effects compared with that seen with nighttime dosing of the IR formulation. Therefore, this controlled-release formulation of amitriptyline may be appropriate for single daily administration.
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Affiliation(s)
- S K Gupta
- Department of Clinical Pharmacology, ALZA Corporation, Mountain View, California 94309-7210, USA
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Schmider J, von Moltke LL, Shader RI, Harmatz JS, Greenblatt DJ. Extrapolating in vitro data on drug metabolism to in vivo pharmacokinetics: evaluation of the pharmacokinetic interaction between amitriptyline and fluoxetine. Drug Metab Rev 1999; 31:545-60. [PMID: 10335452 DOI: 10.1081/dmr-100101935] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Recently, models have been proposed to extrapolate in vitro data on the influence of inhibitors on drug metabolism to in vivo decrement in drug clearance. Many factors influence drug clearance such as age, gender, habits, diet, environment, liver disease, heredity, and other drugs. In vitro investigation of hepatic cytochrome P450 activity has generally centered on genetic influences and interactions with other drugs. This group of enzymes is involved in many, although not all, drug interactions. The interaction of amitriptyline and fluoxetine is an example. Of the different in vitro paradigms, interaction studies utilizing human liver microsomal preparations have proved to be the most generally applicable for in vitro scaling models. Assuming Michaelis-Menten conditions and applying nonlinear regression, a hybrid inhibition constant (Ki) can be generated that allows classification of the inhibitory potency of an inhibitor toward a specific reaction. This constant is largely independent of the substrate concentration, but in vivo relevance is critically dependent on the inhibitor concentration in the site of metabolic activity, the liver cell cytosol. Many lipophilic drugs are extensively bound to plasma protein but, nonetheless, demonstrate extensive partitioning into liver tissue. This is not compatible with diffusion only of the unbound drug fraction into liver cells. The introduction of a partition factor, based on data from a number of possible sources, provided a reasonable basis for the scaling of in vitro data to in vivo conditions. Many interactions could be reconstructed or predicted with greater accuracy and clinical relevance for interactions such as terfenadine or midazolam and ketoconazole. Even for less marked interactions such as amitriptyline and fluoxetine, this model provides a forecast consistent with the clinically observed range of 22-45% reduction in oral clearance, although this interaction is complicated by the presence of two inhibitors, fluoxetine and norfluoxetine. The concept of in vitro-in vivo scaling is promising and might ultimately yield a fast and more cost-effective screening for drug interactions with reduced human drug exposure and risk.
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Affiliation(s)
- J Schmider
- Department of Clinical Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, Massachusetts, USA.
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Abstract
The circadian changes in absorption, tissue distribution and elimination of amitriptyline after single intravenous (i.v.) and intragastric (i.g.) administration, as well as the differences in pharmacokinetic profile after multiple i.g. administration (at 10:00 and 22:00 h) during a 12 h dosing interval, were investigated. The circadian changes of pharmacokinetic parameters of amitriptyline such as AUC (serum and tissues), clearance (i.v. and i.g.), volume of distribution, biological half-life and bioavailability were estimated. Acrophases for clearance appeared between 19:00 and 21:00 h; the bioavailability was highest during the dark phase at around 04:00 h. Higher values of AUC in serum were observed at the beginning of the light phase. A circadian rhythm of tissue distribution (AUC, K(D)) of amitriptyline with acrophase in the dark phase was observed for brain (12 h period), lung and liver (24 h), but not for heart or kidney. After single (i.v. and i.g.) amitriptyline administration, concentrations of its major metabolite, nortriptyline, were negligible; however, after ten doses, nortriptyline serum and tissue levels were similar to the concentrations of the parent drug with higher values during the day (light phase).
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Affiliation(s)
- A Rutkowska
- Department of Toxicology, School of Medicine, Jagiellonian University, Kraków, Poland.
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