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Strand MC, Mørland J, Slørdal L, Riedel B, Innerdal C, Aamo T, Mathisrud G, Vindenes V. Conversion factors for assessment of driving impairment after exposure to multiple benzodiazepines/z-hypnotics or opioids. Forensic Sci Int 2017; 281:29-36. [PMID: 29101905 DOI: 10.1016/j.forsciint.2017.10.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2017] [Revised: 09/06/2017] [Accepted: 10/11/2017] [Indexed: 11/18/2022]
Abstract
AIMS Norway has introduced legal concentration limits in blood for 28 non-alcohol drugs in driving under the influence cases. As of 2016 this legislation also regulates the assessment of combined effects of multiple benzodiazepines and opioids. We herein describe the employed methodology for the equivalence tables for concentrations of benzodiazepines/z-hypnotics and opioids implemented in the Norwegian Road Traffic Act. METHODS Legislative limits corresponding to impairment at blood alcohol concentrations (BAC) of 0.02%, 0.05% and 0.12% were established for 15 different benzodiazepines and opioids. This was based on a concept of a linear relationship between blood drug concentration and impairment in drug naïve users. Concentration ratios between these drugs were used to establish conversion factors and calculate net impairment using diazepam and morphine equivalents. RESULTS Conversion factors were established for 14 benzodiazepines/z-hypnotics (alprazolam, bromazepam, clobazam, clonazepam, etizolam, flunitrazepam, lorazepam, nitrazepam, nordiazepam, oxazepam, phenazepam, temazepam, zolpidem and zopiclone) and two opioids (methadone and oxycodone). CONCLUSIONS Conversion factors to calculate diazepam and morphine equivalents for benzodiazepines/z-hypnotics and selected opioids, respectively, have been operative in the Norwegian Road Traffic Act as of February 2016. Calculated equivalents can be applied by the courts to meter out sanctions.
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Affiliation(s)
| | - Jørg Mørland
- Norwegian Institute of Public Health, Division of Health Data and Digitalization, Oslo, Norway.
| | - Lars Slørdal
- Department of Laboratory Medicine, Children's and Women's Health, Norwegian University of Science and Technology, Trondheim, Norway; Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.
| | - Bettina Riedel
- University of Bergen, Faculty of Medicine and Dentistry, Department of Clinical Science, Bergen, Norway; Haukeland University Hospital, Laboratory of Clinical Biochemistry, Bergen, Norway.
| | | | - Trond Aamo
- Department of Clinical Pharmacology, St. Olav University Hospital, Trondheim, Norway.
| | - Grete Mathisrud
- Norwegian Ministry of Transport and Communications, Department of Public Roads and Traffic Safety, Oslo, Norway.
| | - Vigdis Vindenes
- Oslo University Hospital, Department of Forensic Medicine, Oslo, Norway; Center of Drug and Addiction Research, Faculty of Medicine, University of Oslo, Norway.
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Tsutsumi K, Iwao M, Kotegawa T, Imai H, Ohashi K, Nakano S. Determination of Triazolam and Midazolam in Human Plasma Using Gas Chromatography with Microelectron Capture Detection for Clinical Application. YAKUGAKU ZASSHI 2014; 134:119-25. [DOI: 10.1248/yakushi.13-00153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Kimiko Tsutsumi
- Department of Clinical Pharmacology and Therapeutics, Oita University Faculty of Medicine
| | - Miyuki Iwao
- Department of Clinical Pharmacology and Therapeutics, Oita University Faculty of Medicine
| | - Tsutomu Kotegawa
- Department of Clinical Pharmacology and Therapeutics, Oita University Faculty of Medicine
| | - Hiromitsu Imai
- Department of Clinical Pharmacology and Therapeutics, Oita University Faculty of Medicine
| | - Kyoichi Ohashi
- Department of Clinical Pharmacology and Therapeutics, Oita University Faculty of Medicine
| | - Shigeyuki Nakano
- Department of Clinical Pharmacology and Therapeutics, Oita University Faculty of Medicine
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Brown T, Milavetz G, Murry DJ. Alcohol, drugs and driving: implications for evaluating driver impairment. ANNALS OF ADVANCES IN AUTOMOTIVE MEDICINE. ASSOCIATION FOR THE ADVANCEMENT OF AUTOMOTIVE MEDICINE. ANNUAL SCIENTIFIC CONFERENCE 2013; 57:23-32. [PMID: 24406943 PMCID: PMC3861813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Impaired driving is a significant traffic safety problem, and alcohol and drugs taken before driving contribute substantially to this problem. With the increase in use of prescription medication and the decriminalization of some drugs, it has become increasingly important to understand the manifestation of driver impairment. Building upon previous alcohol research conducted at the National Advanced Driving Simulator (NADS), this study enrolled commercial bus drivers to evaluate the effect of triazolam on driving performance to assess difference between placebo, 0.125, and 0.25 mg doses in a randomized and double-blind design. On each of three randomized visits, subjects drove a simulator scenario that had previously been used to demonstrate effects of alcohol on driving performance. Plasma triazolam levels were obtained before the simulator drive. The protocol included participants receiving study medication and placebo over a 3-week period of time one to two weeks apart. The simulator drives used for this analysis occurred approximately 140 minutes after dosing-after the subjects had completed four bus simulator drives and neuropsychological tests over a 2-hour period of time surrounding dosing. The driving scenario contained representative situations on three types of roadways (urban, freeway, and rural) under nighttime driving conditions. Lane keeping performance (ability to drive straight in the lane) under the three doses of triazolam demonstrates that at the 0.25 mg dose, statistically significant effects on performance are observed, but no effects are found at the 0.125 mg level when testing at this time period after dosing. This differs from the effects of alcohol, which shows impairing effects at a 0.05% blood alcohol concentration (BAC) and a greater effect at 0.10% BAC. These results demonstrate the importance of understanding how different types of drugs affect driving performance in realistic driving environments. Although some compounds may have an effect that correlates linearly to dosage, that is not always the case. An understanding of these differences and how they vary across driving tasks is essential to developing a robust evaluation protocol that can accurately describe the effects of a wide variety of drugs on driver impairment. This information can be used to reduce the risk of deleterious effects of therapeutic medications while ensuring their safe and beneficial use.
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Affiliation(s)
- Timothy Brown
- National Advanced Driving Simulator, Center for Computer Aided Design, The University of Iowa, Iowa City, Iowa
| | - Gary Milavetz
- College of Pharmacy, The University of Iowa, Iowa City, Iowa
| | - Daryl J Murry
- College of Pharmacy, The University of Iowa, Iowa City, Iowa
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Abstract
INTRODUCTION The imidazopyridine derivative zolpidem , which acts as a benzodiazepine (BZ) receptor agonist, is the most widely prescribed hypnotic drug in the US. AREAS COVERED This review addresses the neuroreceptor properties of zolpidem; clinical pharmacokinetics, pharmacodynamics and drug interactions; efficacy as a hypnotic; adverse effects; tolerance, dependence and withdrawal; relation to motor vehicle accidents and complex sleep behaviors; and new dosage forms. EXPERT OPINION Approved doses of zolpidem (10 mg for adults, 5 mg for the elderly) are consistently effective in reducing sleep latency and consequently increasing sleep duration in patients with insomnia. However, favorable effects on sleep maintenance are observed less consistently. Residual daytime effects are unlikely with recommended doses, and provided that at least 8 h elapse prior to arising. Hypnotic efficacy is maintained with repeated nightly use, and the risk of rebound insomnia is low. Dependence and abuse of zolpidem are no more likely to occur than with typical benzodiazepines. Newly available novel dosage forms of zolpidem have increased therapeutic options for patients with insomnia variants such as sleep maintenance insomnia and middle-of-the-night awakening.
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Affiliation(s)
- David J Greenblatt
- Tufts University School of Medicine, Department of Molecular Physiology and Pharmacology, 136 Harrison Avenue, Boston, MA 02111, USA.
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5
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Physiologically based mechanistic modelling to predict complex drug–drug interactions involving simultaneous competitive and time-dependent enzyme inhibition by parent compound and its metabolite in both liver and gut—The effect of diltiazem on the time-course of exposure to triazolam. Eur J Pharm Sci 2010; 39:298-309. [DOI: 10.1016/j.ejps.2009.12.002] [Citation(s) in RCA: 147] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Accepted: 12/10/2009] [Indexed: 01/16/2023]
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Abstract
The present study compared the acute dose effects of the benzodiazepine triazolam and the anticholinergic scopolamine on metamemory (knowledge and awareness of one's own memory) in a two-phase paradigm designed to assess effects on both monitoring and control components of metamemory in both semantic (general knowledge) and episodic memory (cued-recall) tasks. Placebo and 2 doses each of triazolam (0.125, 0.25 mg/70 kg, oral) and scopolamine (0.25, 0.50 mg/70 kg, subcutaneous) were administered to 80 healthy volunteers (16 per group) in a double-blind, double-dummy, independent groups design. Both triazolam and scopolamine impaired episodic memory (quantity and accuracy) but not semantic memory. Results suggested that both drugs impaired monitoring as reflected in absolute accuracy measures (impaired calibration in the direction of overconfidence) and control sensitivity (the relationship between confidence and behavior). Overall, the results did not provide evidence for differences between triazolam and scopolamine in memory or metamemory. In addition to the clinical relevance of the observed effects, this study adds to the accumulating body of cognitive psychopharmacological research illustrating the usefulness of drug-induced amnesia as a vehicle to explore memory and metamemory.
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Affiliation(s)
- Miriam Z Mintzer
- Department of Psychiatry and Behavioral Sciences, Behavioral Biology Research Center, Johns Hopkins University School of Medicine, 5510 Nathan Shock Drive, Baltimore, MD 21224, USA.
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Nano-bio-technology and sensing chips: new systems for detection in personalized therapies and cell biology. SENSORS 2010; 10:526-43. [PMID: 22315554 PMCID: PMC3270855 DOI: 10.3390/s100100526] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 12/30/2009] [Accepted: 01/05/2010] [Indexed: 11/17/2022]
Abstract
Further advances in molecular medicine and cell biology also require new electrochemical systems to detect disease biomarkers and therapeutic compounds. Microelectronic technology offers powerful circuits and systems to develop innovative and miniaturized biochips for sensing at the molecular level. However, microelectronic biochips proposed in the literature often do not show the right specificity, sensitivity, and reliability required by biomedical applications. Nanotechnology offers new materials and solutions to improve the surface properties of sensing probes. The aim of the present paper is to review the most recent progress in Nano-Bio-Technology in the area of the development of new electrochemical systems for molecular detection in personalized therapy and cell culture monitoring.
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Expanded studies of the pharmacokinetics and clinical effects of multidose sublingual triazolam in healthy volunteers. J Clin Psychopharmacol 2009; 29:426-31. [PMID: 19745641 PMCID: PMC2881333 DOI: 10.1097/jcp.0b013e3181b5f45e] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Previous work described the pharmacokinetics and clinical effects of multidose sublingual triazolam (Halcion; Pharmacia & Upjohn Co, Kalamazoo, Mich). This laboratory study evaluated the hypothesis that incremental dosing of triazolam produces dose-dependent central nervous system depression that is profound and long lasting. Forty-nine healthy adults between the ages of 21 and 39 years, not receiving dental treatment, were randomly assigned to placebo (n = 12) or 1 of 3 triazolam groups (0.25-mg single dose, n = 12; 0.5 mg divided between 2 equal doses for 60 minutes, n = 12; or 0.75 mg divided among 3 doses for 90 minutes, n = 13). Plasma triazolam concentrations were determined. Bispectral index (BIS) and the Observer Assessment of Alertness/Sedation scale were used to assess sedation. Plasma triazolam concentrations increased with time in all subjects, with Tmax and Cmax both increasing dose dependently. Compared with placebo, all dosing paradigms produced dose-dependent BIS suppression and sedation. The single dose of 0.25 mg reached its peak BIS suppression at 90 (81 +/- 7) minutes and sedation at 120 (3.6 +/- 0.5) minutes and returned to baseline before 360 minutes. In contrast, incremental dosing of 0.5 and 0.75 mg produced profound and long-lasting BIS suppression and sedation that did not plateau until either 180 or 210 minutes as measured by the BIS index (67 +/- 14 and 60 +/- 16 at 0.5 and 0.75 mg, respectively) and 150 minutes as measured by the Observer Assessment of Alertness/Sedation scale (3.2 +/- 1.0 and 2.7 +/- 0.4 at 0.5 and 0.75 mg, respectively). These data more fully characterize the effects of incremental dosing with sublingual triazolam and provide additional insight for discharge safety recommendations.
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Takayasu T, Ishida Y, Kimura A, Kondo T. Determination of triazolam and its metabolites 1-hydroxymethyltriazolam and 4-hydroxytriazolam in eight autopsy cases by GC-MS. Forensic Toxicol 2009. [DOI: 10.1007/s11419-009-0075-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Choi L, Caffo B, Rohde C. A survey of the likelihood approach to bioequivalence trials. Stat Med 2009; 27:4874-94. [PMID: 18618422 DOI: 10.1002/sim.3334] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Bioequivalence (BE) trials are abbreviated clinical trials whereby a generic drug or new formulation is evaluated to determine if it is 'equivalent' to a corresponding previously approved brand-name drug or formulation. In this paper, we survey the process of testing BE and advocate the likelihood paradigm for representing the resulting data as evidence. We emphasize the unique conflicts between hypothesis testing and confidence intervals in this area--which we believe are indicative of the existence of the systemic defects in the frequentist approach--that the likelihood paradigm avoids. We suggest the direct use of profile likelihoods for evaluating BE. We discuss how the likelihood approach is useful to present the evidence for both average and population BE within a unified framework. We also examine the main properties of profile likelihoods and estimated likelihoods under simulation. This simulation study shows that profile likelihoods offer a viable alternative to the (unknown) true likelihood for a range of parameters commensurate with BE research.
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Affiliation(s)
- Leena Choi
- Department of Biostatistics, School of Medicine, Vanderbilt University, 1161 21st Ave. South MCN S-2323, Nashville, TN 37232-2158, USA.
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11
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Rawden HC, Carlile DJ, Tindall A, Hallifax D, Galetin A, Ito K, Houston JB. Microsomal prediction ofin vivoclearance and associated interindividual variability of six benzodiazepines in humans. Xenobiotica 2008; 35:603-25. [PMID: 16192111 DOI: 10.1080/00498250500162870] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The intrinsic clearances (CLint) of midazolam, triazolam, diazepam, nordiazepam, flunitrazepam and alprazolam were determined from two liver banks (n=21) by formation kinetics of ten metabolites. A literature-collated database of in vivo CLint values (811 subjects) was used to assess predictions and variability. The in vivo clearance of six benzodiazepines was generally underpredicted by in vitro data and the degree of bias was in agreement with a database of structurally diverse compounds (n=37). The variability observed for in vitro clearances (11--19--fold for midazolam, diazepam and nordiazepam in liver bank 1; 101--269--fold for triazolam, flunitrazepam and alprazolam in liver bank 2) exceeded the in vivo variability for the same compounds (4--59 and 10--29, respectively). This mismatch may contribute to the bias in microsomal predictions and it highlights the need for careful selection of representative livers for human liver banks.
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Affiliation(s)
- H C Rawden
- School of Pharmacy and Pharmaceutical Sciences, University of Manchester, Manchester, UK
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12
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13
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Mintzer MZ, Kuwabara H, Alexander M, Brasic JR, Ye W, Ernst M, Griffiths RR, Wong DF. Dose effects of triazolam on brain activity during episodic memory encoding: a PET study. Psychopharmacology (Berl) 2006; 188:445-61. [PMID: 16847681 DOI: 10.1007/s00213-006-0446-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2006] [Accepted: 05/17/2006] [Indexed: 02/01/2023]
Abstract
RATIONALE Although it is well established that acute benzodiazepine administration impairs episodic memory encoding, little is known about the neuroanatomical substrates of this effect. OBJECTIVE The objective was to examine the acute dose effects of the benzodiazepine hypnotic triazolam on brain activity during episodic memory encoding. METHODS After oral capsule administration (placebo, 0.1, 0.2, and 0.4 mg/70 kg triazolam), regional cerebral blood flow (rCBF) was measured using positron emission tomography (PET) with 15O-H2O during performance of semantic categorization and orthographic categorization tasks in a double-blind, within-subject design in 12 healthy volunteers. The rCBF associated with episodic memory encoding was measured by subtracting the rCBF during orthographic categorization from that during semantic categorization and by examining correlations between brain activity during encoding and subsequent recognition memory performance. RESULTS Results in the placebo condition replicated those of nonpharmacological encoding studies, including activation in left ventrolateral prefrontal cortex. Correlations between brain activity and subsequent memory performance additionally showed medial temporal activation. Triazolam produced dose-related impairment in memory performance and dose-related deactivation in encoding-associated areas including right prefrontal cortex, left parahippocampal gyrus, and left anterior cingulate cortex. CONCLUSIONS Results are consistent with behavioral evidence that benzodiazepines impair prefrontal control processes as well as contextual memory and episodic binding processes thought to be controlled by the medial temporal lobe. In addition to elucidating the brain mechanisms underlying these benzodiazepine-induced behavioral deficits, results of this study also help validate hypotheses generated in nonpharmacological neuroimaging studies regarding the processes controlled by these brain regions.
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Affiliation(s)
- Miriam Z Mintzer
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
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Howgate EM, Rowland Yeo K, Proctor NJ, Tucker GT, Rostami-Hodjegan A. Prediction of in vivo drug clearance from in vitro data. I: impact of inter-individual variability. Xenobiotica 2006; 36:473-97. [PMID: 16769646 DOI: 10.1080/00498250600683197] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The Simcyp Population-Based ADME Simulator was used to predict median drug clearances and their associated variance from in vitro data. Fifteen drugs satisfied the entry criteria for the study and the relevant information (in vitro metabolism data and in vivo human clearance values) were collated from the literature. Predicted values of median clearances fell within 2-fold of observed values for 73% of the drugs (oral route) and 78% of the drugs (intravenous route) when microsomal binding was disregarded, and for 93% (oral) and 100% (intravenous) when it was considered. Irrespective of whether microsomal binding was considered, the predicted fold variability fell within 2-fold of the observed variability for 80% (oral) and 67% (intravenous) of the drugs.
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Affiliation(s)
- E M Howgate
- Simcyp Ltd, Blades Enterprise Centre, Sheffield, UK
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15
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Greenblatt DJ. Pharmacokinetic determinants of hypnotic drug action: The art and science of controlling release. Sleep Med 2006. [DOI: 10.1016/j.sleep.2006.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Mintzer MZ, Griffiths RR. An abuse liability comparison of flunitrazepam and triazolam in sedative drug abusers. Behav Pharmacol 2005; 16:579-84. [PMID: 16170235 DOI: 10.1097/01.fbp.0000172736.11994.3c] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The present double-blind, placebo-controlled study compared the acute effects of oral administration of the benzodiazepine hypnotics flunitrazepam (6 mg/70 kg) and triazolam (1 and 2 mg/70 kg) on measures relevant to abuse liability as well as on psychomotor performance and observer- and participant-rated measures of drug effects in nine sedative drug abusers. Analysis of participant-rated measures collected 24 h after drug administration (next-day; assessing the overall effects of the drug received 24 h earlier) indicated that flunitrazepam, but neither triazolam dose, produced significant increases relative to placebo in next-day ratings of drug liking, the amount of money the drug would be worth on the street, and the amount of money the participant would be willing to pay for the drug on the street. Importantly, these abuse liability differences between flunitrazepam and triazolam were present at a dose of flunitrazepam (6 mg/70 kg) that produced overall drug effects that were comparable to, or significantly less than, those of a high triazolam dose (2 mg/70 kg). Consistent with results of a previous study in our laboratory, these results suggest that flunitrazepam may have a greater abuse liability than triazolam, and that this abuse liability difference emerges on measures taken 24 h after drug administration but not on same-day measures.
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Affiliation(s)
- M Z Mintzer
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
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18
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Greenblatt DJ, Gan L, Harmatz JS, Shader RI. Pharmocokinetics and pharmacodynamics of single-dose triazolam: electroencephalography compared with the Digit-Symbol Substitution Test. Br J Clin Pharmacol 2005; 60:244-8. [PMID: 16120062 PMCID: PMC1884767 DOI: 10.1111/j.1365-2125.2005.02409.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Accepted: 12/28/2004] [Indexed: 01/22/2023] Open
Abstract
AIMS To investigate whether the electroencephalogram (EEG) directly reflects the CNS effects of benzodiazepines by evaluating the relation of the EEG to plasma drug concentrations and to Digit-Symbol Substitution Test (DSST) scores after a single dose of triazolam, a representative benzodiazepine agonist. METHODS Thirteen healthy male subjects were given 0.375 mg triazolam or placebo in a double-blind crossover study. Plasma samples were collected during 8 h after dosage. Pharmacodynamic effects were measured by DSST and EEG at corresponding times. RESULTS Pharmacokinetic parameters for triazolam were consistent with established values. Compared with placebo, triazolam significantly impaired psychomotor performance on the DSST (P < 0.001) and increased beta amplitude on the EEG (P < 0.002). DSST and EEG changes both closely tracked changes in plasma concentrations over time. The changes for the two measures were highly correlated with each other (r =-0.94, P < 0.001) based on aggregate values at individual time points. However, the variations in area under the curve of pharmacodynamic effect vs. time (AUCeffect) measured by either method did not reflect the variations in plasma AUC across individuals. The individual variability in AUCeffect from the EEG was similar to that measured by the DSST. CONCLUSIONS Both the EEG and the DSST reflect the central benzodiazepine agonist effects of triazolam. Intrinsic variability in both measures is similar.
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Affiliation(s)
- David J Greenblatt
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine and Tufts-New England Medical Center, Boston, MA 02111, USA.
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Meléndez J, Galli I, Boric K, Ortega A, Zuñiga L, Henríquez-Roldán CF, Cárdenas AM. Zolpidem and triazolam do not affect the nocturnal sleep-induced memory improvement. Psychopharmacology (Berl) 2005; 181:21-6. [PMID: 15830236 DOI: 10.1007/s00213-005-2228-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 02/05/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE It is widely accepted that sleep facilitates memory consolidation. Hypnotics (e.g., benzodiazepines), which reportedly increase sleep efficiency but also modify sleep architecture, could affect memory improvement that occurs during sleep. OBJECTIVES The present study examined the effects of single doses of two short half-life hypnotics, zolpidem and triazolam, on sleep-induced improvement of memory. METHODS Twenty-two healthy volunteers participated in this randomized, double-blind, crossover study. All subjects received a single oral dose of zolpidem (10 mg), triazolam (0.25 mg) or placebo at 9 P.M.: and slept for 7.5+/-0.2 h. The effect of sleep on memory was investigated by comparing the performance of this group of volunteers with a group of 21 subjects in wakefulness condition. Declarative memory was evaluated by using a free-recall test of ten standard word and seven nonword lists. Subjects memorized the word and nonword lists 1 h before dosing and they were asked to recall the memorized lists 10 h after dosing. Digit symbol substitution test (DSST) and forward and backward digit tests were also given 1 h before and 10 h after dosing. RESULTS Subjects who slept remembered more nonwords than those in wakefulness condition, but they did not recall significantly more standard words. Neither zolpidem nor triazolam affected the enhanced nonword recall observed after sleep. Finally, none of the hypnotics affected the improvement in the DSST performance of subjects who slept. CONCLUSIONS The hypnotics tested did not interfere with the nocturnal sleep-induced improvement of memory.
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Affiliation(s)
- Jaime Meléndez
- Escuela de Psicología, Universidad de Valparaíso, Valparaíso, Chile
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Abstract
It is well-documented that benzodiazepine sedative/hypnotics produce robust dose-dependent memory-impairing effects. However, benzodiazepines also induce marked sedation, as reflected in changes in observer and subjective ratings of arousal and impaired psychomotor performance. Thus, it is possible that the observed amnestic effects are secondary to more global sedative effects, and do not reflect a specific, primary, benzodiazepine effect on memory mechanisms. This study was designed to use the non-specific stimulant d-amphetamine to dissociate the sedative and memory-impairing effects of the benzodiazepine triazolam. Across four sessions, 20 healthy adult volunteers received via oral capsule administration placebo, 0.25 mg/70 kg triazolam alone, 20 mg/70 kg d-amphetamine sulfate alone, and triazolam (0.25 mg/ 70 kg) and d-amphetamine (20 mg/70 kg) conjointly, in a double-blind, staggered dosing, cross-over design. d-Amphetamine significantly reversed the effects of triazolam on all participant rating and psychomotor performance-based measures of sedative effects, and selectively reversed the memory-impairing effects of triazolam on some measures (e.g. working memory assessed by a 2-back task, episodic memory assessed by free recall, metamemory), but not others (e.g. working memory assessed by a digit recall task, episodic memory assessed by recognition memory). Results suggest that benzodiazepines do have specific effects on memory that are not merely a by-product of the drugs' sedative effects, and that the degree to which sedative effects contribute to the amnestic effects may vary as a function of the particular memory process being assessed. In addition to enhancing the understanding of the mechanisms underlying benzodiazepine-induced amnesia, these results may also contribute to a better understanding of the complex relationship between specific memory processes and level of arousal.
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Affiliation(s)
- Miriam Z Mintzer
- Department of Psychiatry and Behavioral Sciences, Behavioural Biology Research Center, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
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Abstract
A 57-year-old man was found dead lying down in a bamboo thicket. Moderate to severe petechiae were present on his conjunctivae, buccal mucosa, and laryngeal mucosa at autopsy. Cardiac chambers contained a normal volume of fluid blood. Moderate atherosclerosis and fatty liver were observed. No remarkable changes, other than congestion in other organs, were observed. Gas chromatographic screening of the stomach contents, blood and urine was positive for triazolam and alpha-hydroxytriazolam that were confirmed by gas chromatography-mass spectrometry. Blood concentrations of triazolam and free alpha-hydroxytriazolam were 62-251 and 10-66 ng/ml, respectively. A substantial amount of triazolam was detected in bile (1130 ng/ml), but not in urine. Free and total alpha-hydroxytriazolam concentrations were 3920 and 7050 ng/ml, respectively, in the bile and 3710 and 9670 ng/ml, respectively, in urine. Organs contained 216-583 ng/g triazolam. The concentration of free alpha-hydroxytriazolam in the kidney (246 ng/g) was higher than in any other organ. Free alpha-hydroxytriazolam was not detected in the liver. The concentrations of total alpha-hydroxytriazolam in the liver and kidney were 784 and 381 ng/g, respectively. Free to total ratios of alpha-hydroxytriazolam were 0.14-0.56 in fluid samples and 0.56-0.92 in tissue samples, except for the liver. A large quantity of triazolam (8.4 mg) remained in the stomach. The victim probably died of postural asphyxia caused by triazolam poisoning.
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Affiliation(s)
- Fumio Moriya
- Department of Legal Medicine, Kochi Medical School, Kohasu, Oko-cho, Nankoku City, Kochi 783-8505, Japan.
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22
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Takayasu T, Kondo T, Sato Y, Ohshima T. Determination of triazolam by GC-MS in two autopsy cases: distribution in body fluids and organs. Leg Med (Tokyo) 2000; 2:206-11. [PMID: 12935707 DOI: 10.1016/s1344-6223(00)80042-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A detailed procedure for analysis of triazolam by GC-MS was constructed in our laboratory. At the concentration of 100 ng/ml, recoveries of triazolam in plasma and urine were 84.9 and 91.0%, respectively. The coefficients of variation in terms of its recovery were 11.5 (plasma) and 10.2% (urine). The detection limit for quantitation by the method was approximately 5 ng/g. This method was applied to two autopsy cases, giving triazolam distribution in body fluids and organs. In one case (33-year-old woman), concentrations of triazolam in the heart blood, urine, brain, lung, liver, kidney, skeletal muscles and stomach contents were 83.9, 741, 106, 165, 507, 293, 125 and 343 ng/g, respectively. From these toxicological data together with autopsy findings, her cause of death was diagnosed as triazolam poisoning. In the other case (45-year-old man), triazolam concentrations in the urine and stomach contents were 7.81 and 41.1 ng/g, respectively, but it could not be detected in the pleural blood; his cause of death was judged to be a traumatic shock, based on autopsy findings.
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Affiliation(s)
- T Takayasu
- Department of Legal Medicine, Kanazawa University Faculty of Medicine, School of Medicine, Kanazawa 920-8640, Japan
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23
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Kamimori GH, Sirisuth N, Greenblatt DJ, Eddington ND. The influence of the menstrual cycle on triazolam and indocyanine green pharmacokinetics. J Clin Pharmacol 2000; 40:739-44. [PMID: 10883415 DOI: 10.1177/00912700022009495] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The aim of this study was to investigate the effects of the menstrual cycle phase on the pharmacokinetics of two high-clearance agents, triazolam and indocyanine green (ICG). Eleven nonsmoking, healthy, eumenorrheic women were enrolled in this study. Triazolam (0.25 mg) was administered orally, and indocyanine green was administered as an i.v. bolus (0.5 mg/kg) during the follicular, ovulatory, and luteal phases of a single menstrual cycle. Blood samples were collected over 10 hours for triazolam and over 30 minutes for ICG. Triazolam and indocyanine green concentrations were quantitated by electron capture gas chromatography and spectrophotometry, respectively. Noncompartmental analysis was used to determine relevant pharmacokinetics parameters, which were statistically assessed using two-way ANOVA (p < 0.05). No statistical differences for triazolam were observed. Vd/F was lower in the luteal phase (107 L) as compared to the follicular (138 L) and ovulatory (133 L) phases. Clearance of triazolam was comparable in the follicular (583 ml/min), ovulatory (565 ml/min), and luteal (538 ml/min) phases. ICG also revealed no significant differences across the phases. These results suggest that the phases of the menstrual cycle do not influence triazolam or ICG pharmacokinetics.
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Affiliation(s)
- G H Kamimori
- Department of Neurobiology and Behavior, Walter Reed Army Institute of Research, Washington, DC, USA
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24
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Smith DA, Abel SM, Hyland R, Jones BC. Human cytochrome P450s: selectivity and measurement in vivo. Xenobiotica 1998; 28:1095-128. [PMID: 9890156 DOI: 10.1080/004982598238859] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Affiliation(s)
- D A Smith
- Department of Drug Metabolism, Pfizer Central Research, Sandwich, UK
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25
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Greenblatt DJ, Wright CE, von Moltke LL, Harmatz JS, Ehrenberg BL, Harrel LM, Corbett K, Counihan M, Tobias S, Shader RI. Ketoconazole inhibition of triazolam and alprazolam clearance: differential kinetic and dynamic consequences. Clin Pharmacol Ther 1998; 64:237-47. [PMID: 9757147 DOI: 10.1016/s0009-9236(98)90172-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Kinetic and dynamic consequences of metabolic inhibition were evaluated in a study of the interaction of ketoconazole, a P4503A inhibitor, with alprazolam and triazolam, two 3A substrate drugs with different kinetic profiles. METHODS In a double-blind, 5-way crossover study, healthy volunteers received (A) ketoconazole placebo plus 1.0 mg alprazolam orally, (B) 200 mg ketoconazole twice a day plus 1.0 mg alprazolam, (C) ketoconazole placebo plus 0.25 mg triazolam orally, (D) 200 mg ketoconazole twice a day plus 0.25 mg triazolam, and (E) 200 mg ketoconazole twice a day plus benzodiazepine placebo. Plasma concentrations and pharmacodynamic parameters were measured after each dose. RESULTS For trial B versus trial A, alprazolam clearance was reduced (27 versus 86 mL/min; P < .002) and apparent elimination half-life (t1/2) prolonged (59 versus 15 hours; P < .03), whereas peak plasma concentration (Cmax) was only slightly increased (16.1 versus 14.7 ng/mL). The 8-hour pharmacodynamic effect areas for electroencephalographic (EEG) beta activity were increased by a factor of 1.35, and those for digit-symbol substitution test (DSST) decrement were increased by 2.29 for trial B versus trial A. For trial D versus trial C, triazolam clearance was reduced (40 versus 444 mL/min; P < .002), t1/2 was prolonged (18.3 versus 3.0 hours; P < .01), and Cmax was increased (2.6 versus 5.4 ng/mL; P < .001). The 8-hour effect area for EEG was increased by a factor of 2.51, and that for DSST decrement was increased by 4.33. Observed in vivo clearance decrements due to ketoconazole were consistent with those anticipated on the basis of an in vitro model, together with in vivo plasma concentrations of ketoconazole. CONCLUSION For triazolam, an intermediate-extraction compound, impaired clearance by ketoconazole has more profound clinical consequences than those for alprazolam, a low extraction compound.
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Affiliation(s)
- D J Greenblatt
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, MA 02111, USA.
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26
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Tan X, Uchida S, Matsuura M, Nishihara K, Iguchi Y, Kojima T. Benzodiazepine effects on human sleep EEG spectra: a comparison of triazolam and flunitrazepam. Life Sci 1998; 63:675-84. [PMID: 9718096 DOI: 10.1016/s0024-3205(98)00318-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The effects of 0.5 mg triazolam (TRI) and 4 mg flunitrazepam (FNZ) on the sleep electroencephalogram (EEG) were studied in eleven (six for TRI, and five for FNZ) healthy young male subjects. C3 EEG channel data of one baseline night, three drug nights and two withdrawal nights were recorded and their analyzed using a fast Fourier transformation (FFT) method. Changes in the 0.5 Hz to 40 Hz power spectrum showed that: 1) both TRI and FNZ increased higher frequency activity and reduced lower frequency activity on the drug nights; 2) on drug nights, NREM sigma frequency power was more strongly enhanced by TRI than FNZ, while the beta power of both NREM and REM was more strongly enhanced by FNZ than TRI; 3) NREM alpha power increased on the second night of withdrawal from both TRI and FNZ; 4) the power spectra for both NREM and REM sleep returned to baseline levels by the fourth night of withdrawal from either TRI or FNZ. These findings suggest that 0.5 mg TRI and 4 mg FNZ have both common and differing pharmacological effects on the central nervous system. Such differences could be caused by differences in the dose, half-life or systemic distribution of these two drugs.
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Affiliation(s)
- X Tan
- Department of Neuropsychiatry, Nihon University School of Medicine
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27
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Karl HW, Milgrom P, Domoto P, Kharasch ED, Coldwell SE, Weinstein P, Leroux B, Awamura K, Mautz D. Pharmacokinetics of oral triazolam in children. J Clin Psychopharmacol 1997; 17:169-72. [PMID: 9169960 DOI: 10.1097/00004714-199706000-00005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The purpose of this study was to determine the pharmacokinetic behavior of triazolam in children. Nine healthy children, aged 6 to 9 years, received oral triazolam (0.025 mg/kg suspended in Kool-Aid, Kraft General Foods, Chicago, IL) before dental treatment. Plasma triazolam concentrations were measured by gas chromatography/mass spectrophotometry at approximately 5, 15, 30, 45, 60, 90, 120, 180, and 240 minutes. A one-compartment model with first-order absorption and varying parameters was used, and estimated concentration curves were obtained for each subject. The observed peak plasma concentration was 8.5 +/- 3.0 ng/mL (mean +/- SD). The observed time to peak plasma concentration was 74 +/- 25 minutes. Elimination half-life was 213 +/- 144 minutes. Substantial recovery from signs and symptoms of clinical sedation required 180 to 240 minutes. The long duration of effect and relatively slow elimination should be noted by clinicians concerned with patient safety.
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Affiliation(s)
- H W Karl
- Department of Anesthesiology, University of Washington, Seattle 98195-7475, USA
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28
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Tomita M, Okuyama T. Application of capillary electrophoresis to the simultaneous screening and quantitation of benzodiazepines. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL APPLICATIONS 1996; 678:331-7. [PMID: 8738039 DOI: 10.1016/0378-4347(95)00512-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Capillary electrophoresis (CE) is an attractive approach for the analysis of drugs in body fluids. We made a simultaneous analysis of nitrazepam, diazepam, estazolam, bromazepam, triazolam and flurazepam using CE with on-column detection at 200 nm. We obtained the best electropherograms under a condition of 5 mM phosphate-borate (pH 8.5) containing 50 mM SDS and 15% methanol. We examined the effect of the sample solvent matrix on the electropherograms obtained, indicating that increasing the methanol content in the sample solvent or the injection volume above a certain threshold limit decreased the resolution. We then focused on application of the CE to the analysis of the drugs in spiked serum, being appropriate for an analysis within 25 min. Linearity, the detection limit, accuracy and reproducibility were established using this method. The calibration curve was linear up to 1 mg/l of serum concentration. The lower limit of detection was 5 pg per injection and 0.025 mg/l of the serum concentration for all the compounds except for flurazepam, for which they were 40 pg/injection and 0.2 mg/l. The detection limits obtained allowed toxicological and pharmacological determinations for nitrazepam, diazepam, estazolam and bromazepam, but not for triazolam and flurazepam. Only toxic blood levels for the latter two benzodiazepines could be quantified by this method. We concluded that the CE could at least be applicable to simultaneous screening for toxic levels of benzodiazepines. We suggest that this technique may offer criminal toxicologists a rapid, simple and adaptable approach for the estimation of many other drugs in body fluids.
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Affiliation(s)
- M Tomita
- Department of Legal Medicine, Kawasaki Medical School, Kurashiki, Japan
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29
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Robin DW, Hasan SS, Edeki T, Lichtenstein MJ, Shiavi RG, Wood AJ. Increased baseline sway contributes to increased losses of balance in older people following triazolam. J Am Geriatr Soc 1996; 44:300-4. [PMID: 8600201 DOI: 10.1111/j.1532-5415.1996.tb00919.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
OBJECTIVE Although it has been stated frequently that older people are more sensitive to benzodiazepines, the relative roles of impaired baseline performance, impaired elimination, and altered responsiveness have not been defined. We evaluated postural sway and plasma triazolam concentrations after administration of placebo and triazolam 0.375 mg in both young and older healthy subjects. DESIGN Double-blind placebo-controlled trial. PARTICIPANTS Nine young and nine older healthy men. INTERVENTION All subjects received triazolam 0.375 mg or placebo on different study days, which were separated by at least 48 hours. MEASUREMENTS Postural sway, visual analog scale of drowsiness, and plasma triazolam levels. RESULTS The older subjects swayed more during triazolam than did the younger subjects, and this resulted in an increased number of losses of balance. This difference appeared to be caused by greater baseline sway in the older subjects rather than higher concentrations or increased responsiveness. A subset of older people had a much greater number of losses of balance during triazolam than did the rest of the subjects, and these individuals could be identified from their baseline sway. CONCLUSIONS In this study, the increase in drug effect seen in the older subjects was of similar magnitude to that of the young, but it resulted in greater postural sway after drug administration than was seen in the young. The higher postural sway and the corresponding increased instability seen in the older subjects may put these older persons at increased risk of drug-related falls. This study also suggests that it should be possible to develop techniques that will identify individuals at particular risk of drug-induced postural instability.
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Affiliation(s)
- D W Robin
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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30
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Wesensten NJ, Balkin TJ, Davis HQ, Belenky GL. Reversal of triazolam- and zolpidem-induced memory impairment by flumazenil. Psychopharmacology (Berl) 1995; 121:242-9. [PMID: 8545530 DOI: 10.1007/bf02245635] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The effects of flumazenil, a benzodiazepine receptor antagonist, on triazolam- and zolpidem-induced memory impairment were investigated. Sixty subjects received oral triazolam 0.5 mg, zolpidem 20.0 mg, or placebo at 10 a.m. (n = 20 per drug). Ninety minutes later, half of the subjects (n = 10) in each oral drug group were administered flumazenil 1.0 mg, while the remaining half received placebo (normal saline), through indwelling venous catheters. Learning/memory tests (including Simulated Escape, Restricted Reminding, Paired-Associates, and Repeated Acquisition) were administered at that time, and at 1.5-h intervals over the next 6 h. Triazolam/placebo and zolpidem/placebo drug combinations impaired memory on all tests (all Ps < 0.05). However, the triazolam/flumazenil and zolpidem/flumazenil groups showed no evidence of impairment during any test session. These results demonstrate that flumazenil 1.0 mg rapidly and lastingly reverses memory impairment caused by agonists of the benzodiazepine receptor. Furthermore, nonsignificant trends suggested that performance of the placebo/flumazenil group was consistently better than that of the placebo/placebo group, denoting a possible role of endogenous benzodiazepine agonists in natural sleep/wake processes.
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Affiliation(s)
- N J Wesensten
- Department of Behavioral Biology, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA
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31
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Kroboth PD, McAuley JW, Kroboth FJ, Bertz RJ, Smith RB. Triazolam pharmacokinetics after intravenous, oral, and sublingual administration. J Clin Psychopharmacol 1995; 15:259-62. [PMID: 7593708 DOI: 10.1097/00004714-199508000-00004] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study was designed to evaluate the relative and absolute bioavailability of triazolam, 0.25 mg, after the administration of the marketed oral tablet and a sublingual prototype wafer; an intravenous dose was used as a reference. Twelve men were evaluated in a three-way crossover study; study days were separated by 1 week. A single dose was administered to each subject at approximately 8 a.m.; serial blood samples were obtained for the determination of triazolam concentration. The fraction absorbed relative to intravenous was 20% higher in the sublingual than in the oral treatment (p = 0.0128); the difference between treatments was greatest in the first 2 hours as indicated by the area under the curve from 0 to 2 hours (p < 0.05). The extraction ratio ranged from 0.05 to 0.25, and the predicted availability after oral administration was 86% with a range of 75 to 95%. In contrast, the observed mean absolute availability was 44% (oral) and 53% (sublingual). A potential explanation for this discrepancy between predicted and observed bioavailability is that after oral administration, a fraction of triazolam may be metabolized by cytochrome P450IIIA4 in the gut wall, with a separate fraction subject to first-pass metabolism in the liver. Although this study was not designed to identify sites of triazolam metabolism, the proposed explanation is consistent with the occurrence of P450IIIA4 in the stomach, small intestine, and liver. Doses administered sublingually avoid first-pass metabolism, producing earlier and higher peak concentrations than do doses administered orally.
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Affiliation(s)
- P D Kroboth
- University of Pittsburgh Pharmacodynamic Research Center, Pennsylvania 15261, USA
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32
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Wesensten NJ, Balkin TJ, Belenky GL. Effects of daytime administration of zolpidem versus triazolam on memory. Eur J Clin Pharmacol 1995; 48:115-22. [PMID: 7589024 DOI: 10.1007/bf00192735] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To determine whether zolpidem (an imidazopyridine hypnotic) produces amnestic effects which are similar to those produced by triazolam (a benzodiazepine hypnotic), 70 subjects were administered either triazolam (0.125, 0.25, or 0.5 mg), zolpidem (5, 10, or 15 mg) or placebo, then tested on Simulated Escape, Restricted Reminding, and Paired-Associates memory tests at 1.5 hours post-dosing (i.e., near the time of estimated peak blood concentration for both drugs) and again at 6 hours post-dosing. Triazolam 0.5 mg produced the greatest memory impairment at both test times, and also produced the greatest degree of sedation during intervening daytime naps in a non-sleep-conducive environment. Other doses of triazolam and zolpidem produced less memory impairment, but also failed to significantly enhance sleep. The results are consistent with the view that the amnestic and hypnotic effects of these sleep-inducing medications are functionally coupled.
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Affiliation(s)
- N J Wesensten
- Department of Behavioral Biology, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA
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33
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von Moltke LL, Greenblatt DJ, Schmider J, Harmatz JS, Shader RI. Metabolism of drugs by cytochrome P450 3A isoforms. Implications for drug interactions in psychopharmacology. Clin Pharmacokinet 1995; 29 Suppl 1:33-43; discussion 43-4. [PMID: 8846621 DOI: 10.2165/00003088-199500291-00007] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Members of the P450 3A subfamily are the most abundant of the human hepatic cytochromes. CYP3A isoforms mediate the biotransformation of many drugs, including a number of psychotropic, cardiac, analgesic, hormonal, immunosuppressant, antineoplastic, and antihistaminic agents. Activity of CYP3A in humans is variable among individuals, but there is no evidence of genetic polymorphism. Significant amounts of CYP3A are present in the gastrointestinal tract, and may contribute to presystemic extraction of drugs such as cyclosporin. The azole antifungal agents ketoconazole and itraconazole are potent inhibitors of human CYP3A isoforms. Selective serotonin reuptake inhibitor (SSRI) antidepressants are also CYP3A inhibitors, but much less potent than ketoconazole or itraconazole. In vitro models can provide important information on the qualitative and quantitative activity of potential inhibitors of human cytochromes. However, in vitro inhibition constant (Ki) values alone do not predict the magnitude of an in vivo interaction, nor whether an interaction will be of clinical importance. For example, SSRIs are predicted to impair clearance of the antihistamine terfenadine in humans. However, the magnitude of this effect is much less than would be associated with a pharmacokinetic interaction of clinical importance.
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Affiliation(s)
- L L von Moltke
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, USA
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34
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Abstract
Polymorphisms have been detected in a variety of xenobiotic-metabolizing enzymes at both the phenotypic and genotypic level. In the case of four enzymes, the cytochrome P450 CYP2D6, glutathione S-transferase mu, N-acetyltransferase 2 and serum cholinesterase, the majority of mutations which give rise to a defective phenotype have now been identified. Another group of enzymes show definite polymorphism at the phenotypic level but the exact genetic mechanisms responsible are not yet clear. These enzymes include the cytochromes P450 CYP1A1, CYP1A2 and a CYP2C form which metabolizes mephenytoin, a flavin-linked monooxygenase (fish-odour syndrome), paraoxonase, UDP-glucuronosyltransferase (Gilbert's syndrome) and thiopurine S-methyltransferase. In the case of a further group of enzymes, there is some evidence for polymorphism at either the phenotypic or genotypic level but this has not been unambiguously demonstrated. Examples of this class include the cytochrome P450 enzymes CYP2A6, CYP2E1, CYP2C9 and CYP3A4, xanthine oxidase, an S-oxidase which metabolizes carbocysteine, epoxide hydrolase, two forms of sulphotransferase and several methyltransferases. The nature of all these polymorphisms and possible polymorphisms is discussed in detail, with particular reference to the effects of this variation on drug metabolism and susceptibility to chemically-induced diseases.
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Affiliation(s)
- A K Daly
- Department of Pharmacological Sciences, University of Newcastle upon Tyne, Medical School, U.K
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35
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Midha KK, Ormsby ED, Hubbard JW, McKay G, Hawes EM, Gavalas L, McGilveray IJ. Logarithmic transformation in bioequivalence: application with two formulations of perphenazine. J Pharm Sci 1993; 82:138-44. [PMID: 8445525 DOI: 10.1002/jps.2600820205] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The rationale for using the logarithmic transformation on concentration-dependent pharmacokinetic parameters a priori is presented. This rationale is based on theoretical pharmacokinetic and statistical grounds, but is also applicable to the practice of physicians in dealing with variations of drug treatment within and between patients. The implications of the transformation on data analysis, specifically analysis of variance, and estimation and inference from the analysis as it pertains to bioequivalence decisions are explored. Implementation of the transformation is shown, with an example of two perphenazine formulations in a single-dose crossover study. It is concluded that the transformation has to be accepted on theoretical grounds because sample sizes are too small in bioequivalence studies and too susceptible to extreme values to state with any certainty the actual distribution of pharmacokinetic parameters or their differences within a subject.
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Affiliation(s)
- K K Midha
- College of Pharmacy, University of Saskatchewan, Saskatoon, Canada
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36
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Edeki T, Robin DW, Prakash C, Blair IA, Wood AJ. Sensitive assay for triazolam in plasma following low oral doses. JOURNAL OF CHROMATOGRAPHY 1992; 577:190-4. [PMID: 1400742 DOI: 10.1016/0378-4347(92)80619-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
At low doses of triazolam currently recommended increased assay sensitivity is required for measurement of low plasma concentrations. A highly sensitive capillary gas chromatographic analytical method with a limit of detection of 0.02 ng/ml was developed and used to describe the pharmacokinetics of triazolam following the oral intake of 0.125, 0.250 and 0.375 mg. Six male subjects were studied with blood sampling at the following times: 0, 15, 30 and 45 min and 1, 1.5, 2.0, 2.5, 3, 4, 5, 6 and 8 h. The mean pharmacokinetic parameters for the three doses, respectively, were as follows: half-life, 2.7 +/- 0.4, 3.2 +/- 0.5 and 3.2 +/- 0.6 h; apparent oral clearance, 302.3 +/- 59.0, 260.2 +/- 67.9 and 328.6 +/- 77.8 ml/min; apparent volume of distribution, 64.3 +/- 9.6, 62.0 +/- 12.6 and 73.3 +/- 7.7 l; time to maximum concentration, 0.7 +/- 0.2, 0.6 +/- 0.1 and 0.8 +/- 0.3 h; maximum concentration, 2.2 +/- 0.3, 4.3 +/- 0.6 and 5.0 +/- 0.5 ng/ml; and the area under the concentration-time curve (AUC) up to 8 h, 6.8 +/- 1.2, 16.8 +/- 2.9 and 19.6 +/- 3.5 ng/ml h; and AUC extrapolated to infinity, 8.5 +/- 1.7, 21.4 +/- 4.4 and 26.3 +/- 7.2 ng/ml h. There were no significant differences in the half-life, clearance, volume of distribution and time to maximum concentration among the three doses. The AUC was significantly different on the three occasions and was linearly correlated with dose: r = 0.64 (p less than 0.005).
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Affiliation(s)
- T Edeki
- Division of Clinical Pharmacology, School of Medicine, Vanderbilt University, Nashville, TN 37232
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37
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Gaudreault P, Guay J, Thivierge RL, Verdy I. Benzodiazepine poisoning. Clinical and pharmacological considerations and treatment. Drug Saf 1991; 6:247-65. [PMID: 1888441 DOI: 10.2165/00002018-199106040-00003] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Benzodiazepines are among the most frequently prescribed drugs worldwide. This popularity is based not only on their efficacy but also on their remarkable safety. Pure benzodiazepine overdoses usually induce a mild to moderate central nervous system depression; deep coma requiring assisted ventilation is rare, and should prompt a search for other toxic substances. The severity of the CNS depression is influenced by the dose, the age of the patient and his or her clinical status prior to the ingestion, and the coingestion of other CNS depressants. In severe overdoses, benzodiazepines can occasionally induce cardiovascular and pulmonary toxicity, but deaths resulting from pure benzodiazepine overdoses are rare. Quantitative determinations of benzodiazepines are not useful in the clinical management of intoxicated patients since there is no correlation between serum concentrations and pharmacological and toxicological effects. Benzodiazepine overdoses occurring during pregnancy rarely induce serious morbidity in mothers or fetuses, although large doses administered near delivery can induce respiratory depression in neonates. The teratogenic potential of benzodiazepines remains controversial, but is probably small if it exists at all. There is clear evidence that the prolonged use of even therapeutic doses of benzodiazepines will lead to dependence. The risk of developing significant withdrawal symptoms is related to dosage and duration of treatment. Prevention of gastrointestinal absorption should be initiated in all intentional benzodiazepine overdoses. Forced diuresis and dialysis techniques are not indicated since they will not significantly accelerate the elimination of these agents. Intravenous administration of flumazenil, a pure benzodiazepine antagonist, effectively reverses benzodiazepine-induced CNS depression.
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Affiliation(s)
- P Gaudreault
- Department of Pediatrics, University of Montreal, Quebec, Canada
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38
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Kudo K, Nagata T, Imamura T, Kage S, Hida Y. Forensic analysis of triazolam in human tissues using capillary gas chromatography. Int J Legal Med 1991; 104:67-9. [PMID: 2054306 DOI: 10.1007/bf01626033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A reliable and sensitive method has been developed to assess the concentrations of the hypnotic drug triazolam in human tissues, including putrefied tissues. The method involves a 3-step solvent extraction, clean-up on a silica gel column and gas chromatography using a nitrogen phosphorus detector and a capillary column. Estazolam was used as an internal standard. The calibration curve was linear over the concentration range 1 ng/g-1 microgram/g and the lower limit of detection was 0.5 ng/g. A forensic study was performed on the toxicological effects of triazolam using putrefied tissues.
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Affiliation(s)
- K Kudo
- Department of Forensic Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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Woo E, Proulx SM, Greenblatt DJ. Differential side effect profile of triazolam versus flurazepam in elderly patients undergoing rehabilitation therapy. J Clin Pharmacol 1991; 31:168-73. [PMID: 2010562 DOI: 10.1002/j.1552-4604.1991.tb03702.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Patients (aged 65 years or older) who were hospitalized for rehabilitation therapy after a cerebrovascular accident or other acute debilitating condition participated in a 6-week controlled clinical trial. After a 2-week period of receiving nightly single-blind placebo, patients were randomly allocated to receive either triazolam (0.125 mg) or flurazepam hydrochloride (15 mg) nightly under double-blind conditions. For the final 2 weeks, patients again received single-blind placebo. The study groups' were comparable in their performance on four psychomotor tests done in the morning during the initial placebo period. Triazolam-treated patients showed subsequent improvement on the tests, consistent with practice effects, whereas flurazepam recipients showed performance impairment during treatment. Triazolam-flurazepam differences were significant in the card-sorting and arithmetic tests, and they approached significance for the Purdue pegboard test. Blind ratings by physical therapists indicated significant impairment among flurazepam recipients in their capacity to cooperate with and participate in the rehabilitation tasks; the impairment persisted into the post-treatment placebo period. Similar flurazepam-triazolam differences, although not significant, were reported by occupational therapy and nursing staff members. The findings suggest that the kinetic differences between flurazepam and triazolam may have clinical implications in elderly patients undergoing rehabilitation therapy.
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Affiliation(s)
- E Woo
- Department of Medicine, Spaulding Rehabilitation Hospital, Boston, Massachusetts
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Gupta SK, Ellinwood EH, Nikaido AM, Heatherly DG. Simultaneous modeling of the pharmacokinetic and pharmacodynamic properties of benzodiazepines. II. Triazolam. Pharm Res 1990; 7:570-6. [PMID: 2367325 DOI: 10.1023/a:1015805908792] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This study compares the time course of triazolam effects on psychomotor and cognitive skills with triazolam plasma concentrations in a combined pharmacokinetic-pharmacodynamic (sigmoid-Emax) model. Ten male subjects received a single oral dose (1 mg) of triazolam or placebo. The CNS impairment effects were measured by using computerized tracking, body sway, and digit symbol substitution tests, and triazolam plasma concentration was measured by gas chromatography. The drug-induced effect changes lagged behind the plasma drug level changes. The magnitude of the time lag was quantified by the half-time of equilibration between concentrations in the hypothetical effect compartment and the plasma triazolam levels (t 1/2 keo). Essentially the same t 1/2 keo (approximately 6 min) was found for subcritical tracking, body sway, and digit symbol substitution tests. When using the predicted drug concentrations at the effect site, the hysteresis of the plasma concentration-effect disappears, suggesting that the hysteresis is not caused by drug induced tolerance. Moreover, the model allows for estimation of the effect site concentration that causes one-half of the maximal predicted effect (EC50, approximately 5 ng/ml) which is a measure of an individual's sensitivity to triazolam. On the basis of the EC50 values of the effect measures, body sway was slightly less sensitive to triazolam than subcritical tracking and digit symbol substitution tests.
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Affiliation(s)
- S K Gupta
- Department of Psychiatry, Duke University Medical Center, Durham, North Carolina 27710
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41
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Greenblatt DJ, Miller LG, Shader RI. Neurochemical and pharmacokinetic correlates of the clinical action of benzodiazepine hypnotic drugs. Am J Med 1990; 88:18S-24S. [PMID: 1968714 DOI: 10.1016/0002-9343(90)90281-h] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Benzodiazepine derivatives are presumed to exert their pharmacologic activity via interaction with specific molecular recognition sites, termed benzodiazepine receptors, within the brain. The various benzodiazepines used in clinical practice differ considerably in their intrinsic receptor affinity, but the qualitative character of the drug-receptor interaction is similar or identical among this class of drugs. All benzodiazepines are lipophilic (lipid-soluble) substances that relatively rapidly cross the blood-brain barrier and equilibrate with brain tissue. After equilibrium is attained, a constant brain:plasma ratio is maintained, such that plasma concentrations proportionately reflect concentrations of drug in brain. Brain concentrations are proportional to the extent of receptor occupancy, which in turn determines the acute behavioral effect. Clinical differences among benzodiazepines largely reflect differences in pharmacokinetic properties. The onset of action after single oral doses reflects the rate of absorption from the gastrointestinal tract, whereas the duration of action is determined by the rate and extent of drug distribution to peripheral tissues, as well as by the rate of elimination and clearance. During multiple dosage, long half-life drugs accumulate, with the concurrent possibility of daytime sedation. However, a benefit of long half-life drugs is that rebound insomnia on abrupt termination is unlikely. Short half-life drugs accumulate minimally and have a lower likelihood of producing daytime sedation. However, they may be more likely to produce rebound insomnia on abrupt discontinuation.
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Affiliation(s)
- D J Greenblatt
- Department of Psychiatry, Tufts University School of Medicine, Boston, Massachusetts 02111
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Aantaa R, Salonen M, Nyrke T. Difference in action between oral triazolam and zopiclone. Eur J Clin Pharmacol 1990; 38:47-51. [PMID: 2328747 DOI: 10.1007/bf00314802] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effects of oral triazolam 0.25 mg and zopiclone 7.5 mg in 7 supine volunteers were compared by means of quantitative measurements of the EEG, saccadic eye movements, visual analogue scale (VAS) for alertness, critical flicker fusion frequency (CFF) and the Maddox wing. Zopiclone reached its maximum effect earlier (62 min) than triazolam (91 min; CFF). On linear regression analysis the average rate constant (regression coefficient) of onset of action of zopiclone was significantly greater than that of triazolam (0.29 vs. 0.17). Triazolam and zopiclone had similar effects, but zopiclone seemed to have a faster onset of action, probably indicating swifter absorption in supine subjects. Quantitative EEG evaluation gave parallel results to the other parameters used, but triazolam and zopiclone showed a dissimilar mechanism of action, as characterized by changes in the alpha frequency.
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Affiliation(s)
- R Aantaa
- Department of Anaesthesiology, Turku University Central Hospital, Finland
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Greenblatt DJ, Harmatz JS, Friedman H. Arithmetic versus harmonic mean values of elimination half-life: a study of triazolam. J Clin Pharmacol 1989; 29:655-6. [PMID: 2760259 DOI: 10.1002/j.1552-4604.1989.tb03395.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- D J Greenblatt
- Department of Psychiatry, Tufts University School of Medicine, Boston, Massachusetts
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Abstract
The assay methods used to determine the concentrations of the newer benzodiazepines include electron-capture gas-liquid chromatography, high performance liquid chromatography with ultraviolet detection, gas chromatography-mass spectrometry, radioassay and radioreceptor assay. The method used frequently is the highly sensitive and specific electron-capture gas-liquid chromatography. Other methods are associated with limitations. The triazolo- and imidazolebenzodiazepines differ structurally from the 'classical' benzodiazepines such as diazepam, and offer distinct differences in pharmacological activity and in time-course of effect. Alprazolam and triazolam, both 1,4-triazolobenzodiazepines, have high affinities for the benzodiazepine receptor as do midazolam and loprazolam, which are 1,4-imidazolebenzodiazepines. Absorption is characteristically rapid, with peak alprazolam and triazolam concentrations occurring within 1 hour after oral administration. Sublingual administration results in peak alprazolam and triazolam concentrations that are higher and occur earlier than with the oral route. The volume of distribution of alprazolam and triazolam is approximately 1L. Alprazolam is 70% bound to plasma proteins and the extent of binding is independent of concentration. Similarly, triazolam is approximately 85% bound to plasma proteins, variability in binding being explained by variations in alpha 1-acid glycoprotein concentration. The 1,4-triazolo ring prevents the oxidative metabolism of the classical benzodiazepines which results in formation of active metabolites with long elimination half-lives. Alprazolam is extensively metabolised: 29 metabolites have been identified in the urine, and its major metabolite, alpha-hydroxyalprazolam, has pharmacological activity. alpha-Hydroxyalprazolam and 4-hydroxyalprazolam are detectable in plasma in amounts which account for less than 10% of the administered dose. Mean alprazolam elimination half-life in healthy adult subjects ranges from 9.5 to 12 hours; liver disease prolongs alprazolam elimination, but renal insufficiency does not. Triazolam also undergoes oxidation and subsequent glucuronidation. alpha-Hydroxytriazolam is the major metabolite, in addition to which 4-hydroxyalprazolam and alpha-4-hydroxytriazolam have been identified in plasma and urine. The elimination half-life of triazolam ranges between 1.8 and 5.9 hours, while that of the conjugated metabolites is short, approximately 3.8 hours. Accumulation of triazolam or its metabolites after multiple doses does not occur. Liver disease prolongs triazolam elimination from the body, but renal disease does not.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- P D Garzone
- Center for Pharmacodynamic Research, University of Pittsburgh, Pennsylvania
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45
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Sunter JP, Bal TS, Cowan WK. Three cases of fatal triazolam poisoning. BMJ (CLINICAL RESEARCH ED.) 1988; 297:719. [PMID: 3147739 PMCID: PMC1834083 DOI: 10.1136/bmj.297.6650.719] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- J P Sunter
- Department of Pathology, Queen Elizabeth Hospital, Gateshead, Tyne and Wear
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Friedman H, Greenblatt DJ, Burstein ES, Scavone JM, Harmatz JS, Shader RI. Triazolam kinetics: interaction with cimetidine, propranolol, and the combination. J Clin Pharmacol 1988; 28:228-33. [PMID: 3360971 DOI: 10.1002/j.1552-4604.1988.tb03137.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Nineteen healthy volunteers received a single 0.5-mg oral dose of triazolam on four occasions under the following conditions: (1) triazolam alone; (2) triazolam with cimetidine, 300 mg four times daily; (3) triazolam with propranolol, 40 mg four times daily; (4) triazolam with both cimetidine and propranolol. Triazolam kinetics were determined from multiple plasma concentrations measured during 24 hours after each dose. Compared with control, peak plasma triazolam concentration (Cmax) was significantly increased by cimetidine (5.4 versus 3.9 ng/mL), total area under the plasma concentration curve (AUC) increased (21.3 versus 16.1 ng/mL X hr), and oral clearance decreased (485 versus 668 mL/min). However triazolam half-life was not increased. During propranolol alone, triazolam Cmax (4.1 ng/mL), AUC (14.3 ng/mL X hr), and clearance (759 mL/min) did not differ significantly from control, whereas kinetic variables for triazolam with cimetidine plus propranolol were similar to those with cimetidine alone. Plasma free fraction for triazolam (17 to 18% unbound) did not differ significantly among the four treatment conditions. Mean steady-state plasma cimetidine concentrations during trials 2 and 4 were similar (1.04 versus .98 micrograms/mL), whereas plasma propranolol was significantly higher during cimetidine plus propranolol than with propranolol alone (47 versus 29 ng/ml, P less than .001). Thus cimetidine coadministration significantly inhibits triazolam clearance, causing increased triazolam AUC and Cmax, but without a prolongation in half-life. Propranolol itself does not impair triazolam clearance, nor does propranolol potentiate the inhibitory effect of cimetidine alone.
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Affiliation(s)
- H Friedman
- Department of Psychiatry, Tufts University School of Medicine, Boston, Massachusetts 02111
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Greenblatt DJ, Harmatz JS, Zinny MA, Shader RI. Effect of gradual withdrawal on the rebound sleep disorder after discontinuation of triazolam. N Engl J Med 1987; 317:722-8. [PMID: 3306380 DOI: 10.1056/nejm198709173171202] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Sixty volunteers with insomnia participated in a randomized, double-blind, controlled clinical trial. After an initial six nights of placebo, 30 subjects (the abrupt-withdrawal group) received 0.5 mg of triazolam nightly for 7 to 10 nights, after which they received placebo. The other 30 subjects (the tapered-dosage group) received the same initial placebo treatment, then triazolam at 0.5 mg for seven nights, at 0.25 mg for two nights, and at 0.125 mg for two nights, and then placebo. As compared with the initial placebo period, the triazolam period significantly reduced the interval before the onset of sleep (sleep latency), and it prolonged sleep duration, reduced the number of awakenings, and improved the self-rated soundness of sleep in all cohorts. In the abrupt-withdrawal group, plasma levels of triazolam were undetectable the morning after the first night of placebo substitution, and subjects reported prolongation of sleep latency (57 minutes longer than base line), reduction in sleep duration (1.4 hours less than base line), and increased awakenings (1.2 per night above base line). The symptoms of rebound sleep disorder lasted one or possibly two nights, and there was a reversion toward base line on subsequent placebo nights. In the tapered-dosage group, however, plasma triazolam levels fell gradually to zero, and rebound symptoms were decreased or eliminated. Thus, rebound sleep disorder following abrupt discontinuation of triazolam can be attenuated by a regimen of tapering.
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