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Wong A, Hoffman RS, Walsh SJ, Roberts DM, Gosselin S, Bunchman TE, Kebede S, Lavergne V, Ghannoum M. Extracorporeal treatment for calcium channel blocker poisoning: systematic review and recommendations from the EXTRIP workgroup. Clin Toxicol (Phila) 2021; 59:361-375. [PMID: 33555964 DOI: 10.1080/15563650.2020.1870123] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Calcium channel blockers (CCBs) are commonly used to treat conditions such as arterial hypertension and supraventricular dysrhythmias. Poisoning from these drugs can lead to severe morbidity and mortality. We aimed to determine the utility of extracorporeal treatments (ECTRs) in the management of CCB poisoning. METHODS We conducted systematic reviews of the literature, screened studies, extracted data, summarized findings, and formulated recommendations following published EXTRIP methods. RESULTS A total of 83 publications (6 in vitro and 1 animal experiments, 55 case reports or case series, 19 pharmacokinetic studies, 1 cohort study and 1 systematic review) met inclusion criteria regarding the effect of ECTR. Toxicokinetic or pharmacokinetic data were available on 210 patients (including 32 for amlodipine, 20 for diltiazem, and 52 for verapamil). Regardless of the ECTR used, amlodipine, bepridil, diltiazem, felodipine, isradipine, mibefradil, nifedipine, nisoldipine, and verapamil were considered not dialyzable, with variable levels of evidence, while no dialyzability grading was possible for nicardipine and nitrendipine. Data were available for clinical analysis on 78 CCB poisoned patients (including 32 patients for amlodipine, 16 for diltiazem, and 23 for verapamil). Standard care (including high dose insulin euglycemic therapy) was not systematically administered. Clinical data did not suggest an improvement in outcomes with ECTR. Consequently, the EXTRIP workgroup recommends against using ECTR in addition to standard care for patients severely poisoned with either amlodipine, diltiazem or verapamil (strong recommendations, very low quality of the evidence (1D)). There were insufficient clinical data to draft recommendation for other CCBs, although the workgroup acknowledged the low dialyzability from, and lack of biological plausibility for, ECTR. CONCLUSIONS Both dialyzability and clinical data do not support a clinical benefit from ECTRs for CCB poisoning. The EXTRIP workgroup recommends against using extracorporeal methods to enhance the elimination of amlodipine, diltiazem, and verapamil in patients with severe poisoning.
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Affiliation(s)
- Anselm Wong
- Austin Toxicology Unit and Emergency Department, Victorian Poisons Information Centre, Austin Health, Heidelberg, Victoria, Australia.,Department of Medicine, School of Clinical Sciences at Monash Health, Monash University, Clayton, Victoria, Australia.,Centre for Integrated Critical Care, University of Melbourne, Melbourne, Victoria, Australia
| | - Robert S Hoffman
- Division of Medical Toxicology, Ronald O. Perelman Department of Emergency Medicine, NYU Grossman School of Medicine, New York, NY, USA
| | - Steven J Walsh
- Department of Emergency Medicine, Division of Medical Toxicology, The Poison Control Center at Children's Hospital of Philadelphia, Einstein Healthcare Network, Philadelphia, PA, USA
| | - Darren M Roberts
- Departments of Renal Medicine and Transplantation and Clinical Pharmacology and Toxicology, St Vincent's Hospital, Sydney, NSW, Australia.,St. Vincent's Clinical School, University of New South Wales, Sydney, NSW, Australia.,Drug Health Clinical Services, Royal Prince Alfred Hospital, Sydney, NSW, Australia
| | - Sophie Gosselin
- Montérégie-Centre Emergency Department, Centre Intégré de Santé et de Services Sociaux (CISSS), Hôpital Charles-Lemoyne, Greenfield Park, QC.,Department of Emergency Medicine, McGill University, Montreal.,Centre Antipoison du Québec, Quebec, Canada
| | - Timothy E Bunchman
- Children's Hospital of Richmond at Virginia Commonwealth University, Richmond, VA, USA
| | - Sofia Kebede
- School of Medicine, St. Peter`s Specialized Hospital Poison Center, Addis Ababa University, Addis Ababa, Ethiopia
| | - Valery Lavergne
- Research Center, CIUSSS du Nord-de-l'île-de-Montréal, Hôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, QC, Canada
| | - Marc Ghannoum
- Research Center, CIUSSS du Nord-de-l'île-de-Montréal, Hôpital du Sacré-Coeur de Montréal, University of Montreal, Montreal, QC, Canada
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Yang QJ, Si L, Tang H, Sveigaard HH, Chow ECY, Pang KS. PBPK Modeling to Unravel Nonlinear Pharmacokinetics of Verapamil to Estimate the Fractional Clearance for Verapamil N-Demethylation in the Recirculating Rat Liver Preparation. Drug Metab Dispos 2015; 43:631-45. [DOI: 10.1124/dmd.114.062265] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
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3
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Anderson P. Pharmacokinetics of calcium channel blocking agents. ACTA PHARMACOLOGICA ET TOXICOLOGICA 2009; 58 Suppl 2:43-57. [PMID: 2940799 DOI: 10.1111/j.1600-0773.1986.tb02520.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Verapamil and nifedipine are the most frequently used calcium channel blocking agents in Sweden at present time. The pharmacokinetics of verapamil has been described both in healthy volunteers as well as in patients with supraventricular arrhythmias, angina pectoris, liver cirrhosis, hypertrophic cardiomyopathy or hypertension. Intravenous pharmacokinetics of nifedipine has been investigated in healthy volunteers and oral pharmacokinetics in healthy volunteers as well as in patients with hypertension. The pharmacokinetics of verapamil and of one of its metabolites, norverapamil, is changed after multiple oral dosing as has been described in patients with supraventricular tachyarrhythmias, angina pectoris or in patients with essential hypertension. Plasma concentration-effect relationships have been established for verapamil in different clinical situations and in a few cases also for nifedipine. An update of the pharmacokinetics of these two important calcium channel blocking agents is presented.
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Sternieri E, Coccia CPR, Pinetti D, Guerzoni S, Ferrari A. Pharmacokinetics and interactions of headache medications, part II: prophylactic treatments. Expert Opin Drug Metab Toxicol 2007; 2:981-1007. [PMID: 17125412 DOI: 10.1517/17425255.2.6.981] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The present part II review highlights pharmacokinetic drug-drug interactions (excluding those of minor severity) of medications used in prophylactic treatment of the main primary headaches (migraine, tension-type and cluster headache). The principles of pharmacokinetics and metabolism, and the interactions of medications for acute treatment are examined in part I. The overall goal of this series of two reviews is to increase the awareness of physicians, primary care providers and specialists regarding pharmacokinetic drug-drug interactions (DDIs) of headache medications. The aim of prophylactic treatment is to reduce the frequency of headache attacks using beta-blockers, calcium-channel blockers, antidepressants, antiepileptics, lithium, serotonin antagonists, corticosteroids and muscle relaxants, which must be taken daily for long periods. During treatment the patient often continues to take symptomatic drugs for the attack, and may need other medications for associated or new-onset illnesses. DDIs can, therefore, occur. As a whole, DDIs of clinical relevance concerning prophylactic drugs are a limited number. Their effects can be prevented by starting the treatment with low dosages, which should be gradually increased depending on response and side effects, while frequently monitoring the patient and plasma levels of other possible coadministered drugs with a narrow therapeutic range. Most headache medications are substrates of CYP2D6 (e.g., beta-blockers, antidepressants) or CYP3A4 (e.g., calcium-channel blockers, selective serotonin re-uptake inhibitors, corticosteroids). The inducers and, especially, the inhibitors of these isoenzymes should be carefully coadministered.
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Affiliation(s)
- Emilio Sternieri
- University of Modena and Reggio Emilia, Division of Toxicology and Clinical Pharmacology, Headache Centre, University Centre for Adaptive Disorders and Headache, Section Modena II, Largo del Pozzo 71, Modena, Italy
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5
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Busse D, Templin S, Mikus G, Schwab M, Hofmann U, Eichelbaum M, Kivistö KT. Cardiovascular effects of (R)- and (S)-verapamil and racemic verapamil in humans: a placebo-controlled study. Eur J Clin Pharmacol 2006; 62:613-9. [PMID: 16823584 DOI: 10.1007/s00228-006-0154-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Accepted: 05/04/2006] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To characterise the comparative potency of optically pure (R)- and (S)-verapamil as regards negative dromotropic effects on atrioventricular (AV) node conduction and to compare the hemodynamic effects of single doses of the enantiomers in healthy volunteers. METHODS Eight healthy volunteers received a single oral dose of 120 mg (S)-verapamil, 480 mg (R)-verapamil, 240 mg racemic verapamil (rac-verapamil) or placebo on 4 separate occasions. Serum concentrations of (R)- and (S)-verapamil were measured up to 24 h. Cardiovascular effects were assessed by electrocardiography, measurement of blood pressure and transthoracic impedance cardiography (cardiac output and total peripheral resistance). The comparative potency of (R)- and (S)-verapamil with regard to prolongation of the PR interval in the surface ECG was estimated by use of the areas under the effect-time and serum concentration-time curves and linear regression analyses of per cent change in PR interval from baseline versus the logarithm of serum (R)- or (S)-verapamil concentration. RESULTS The PR interval was significantly prolonged after all verapamil treatments as compared with placebo. (S)-verapamil was 20.6-21.8 times more potent than (R)-verapamil with regard to negative dromotropic effects. (R)-verapamil caused a significantly greater maximum reduction in the mean arterial pressure (MAP) than placebo [15.9+/-6.8 versus 8.7+/-3.2 mmHg (mean+/-SD); 95% CI on the difference, 0.79-13.7 mmHg; p<0.05], whereas MAP was not affected by the other verapamil treatments. No significant changes were observed in heart rate, cardiac output and total peripheral resistance after any verapamil treatment as compared with placebo. CONCLUSIONS (S)-verapamil was about 20 times more potent than (R)-verapamil with regard to negative dromotropic effects on AV node conduction. (R)-verapamil but not (S)-verapamil significantly reduced the MAP as compared with placebo.
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Affiliation(s)
- Dagmar Busse
- Dr. Margarete Fischer-Bosch Institute of Clinical Pharmacology, Stuttgart, Germany
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6
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Transdermal controlled delivery of verapamil: determination of in vitro/in vivo relationship. J Control Release 1992. [DOI: 10.1016/0168-3659(92)90198-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Abstract
Numerous publications during the past ten years have described the determination of various calcium channel blockers in biological fluids, using gas and liquid chromatographic techniques. Diltiazem, verapamil, flunarizine and a growing number of dihydropyridines belong to this group of drugs, which in most instances are active at low plasma concentrations. From a bioanalytical point of view these compounds have many features in common, such as high lipophilicity and favourable detection properties.
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Affiliation(s)
- M Ahnoff
- Bionalytical Chemistry, AB Hässle, Mölndal, Sweden
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8
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Lundström T, Rydén L. Ventricular rate control and exercise performance in chronic atrial fibrillation: effects of diltiazem and verapamil. J Am Coll Cardiol 1990; 16:86-90. [PMID: 2358610 DOI: 10.1016/0735-1097(90)90461-w] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effects of two calcium channel blockers, diltiazem (270 mg/day) and verapamil (240 mg/day), were studied in 18 patients with chronic atrial fibrillation. During 24 h Holter electrocardiographic monitoring, mean ventricular rate (beats/min) decreased from 88 +/- 14 with placebo to 76 +/- 13 (p less than 0.001) with diltiazem and 80 +/- 11 (p less than 0.01) with verapamil. Maximal symptom-limited exercise tolerance (W) increased from 127 +/- 39 during the placebo period to 136 +/- 42 (p less than 0.01) with diltiazem and 137 +/- 39 (p less than 0.01) with verapamil. Ventricular rate and rate-pressure product were lower at rest and during exercise with diltiazem and verapamil than with placebo (p less than 0.001), with the drugs being similarly effective. Ventricular rate at maximal exercise (beats/min) was 179 +/- 13 with placebo compared with 159 +/- 21 with diltiazem and 158 +/- 23 with verapamil. Maximal oxygen uptake (ml/kg per min) was 22.3 +/- 4.5 with placebo, 23.7 +/- 4.9 (p less than 0.05) with diltiazem and 22.9 +/- 4.5 with verapamil (p = NS). Respiratory gas exchange anaerobic threshold was reached at a work load (W) of 76 +/- 21 with placebo, 84 +/- 27 (p less than 0.05) with diltiazem and 85 +/- 23 (p less than 0.01) with verapamil. In conclusion, patients with chronic atrial fibrillation have modestly improved exercise tolerance with calcium channel blockade therapy. The dromotropic responses and the effects on physical performance are of similar magnitude for diltiazem and verapamil.
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Affiliation(s)
- T Lundström
- Department of Cardiology, Central Hospital, Skövde, Sweden
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9
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Husum D, Johnsen A, Jensen G. Requirements for drug monitoring of verapamil: experience from an unselected group of patients with cardiovascular disease. PHARMACOLOGY & TOXICOLOGY 1990; 66:163-9. [PMID: 2333271 DOI: 10.1111/j.1600-0773.1990.tb00726.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Serum verapamil and metabolite concentrations were determined by HPLC in 29 patients in routine treatment with verapamil, and 23 were in steady state. Dosage levels and corresponding mean trough levels (+/- S.D.) were as follows: 120 mg daily: 79.1 (+/- 77) nmol/l, 240 mg daily: 173.3 (+/- 200.1) nmol/l, 360 mg daily: 204 (+/- 110.2) nmol/l and 480 mg daily: 361.0 (+/- 231.4) nmol/l. The variation coefficients were 97.3, 115.4, 54.0, and 62.1, respectively, thus showing considerable interpatient variation. Repeated determination of trough levels showed, in contrast, only small intrapatient variation (variation coefficient 35.8, 1.9, and 7.4, at the dosage levels 120, 240 and 340 mg per day). No significant correlation was found between serum verapamil levels age, sex, or weight. No significant effect of digoxin on the concentration of serum verapamil was found. No relation was observed between serum verapamil concentrations and desired effect or side-effects. Two patients showed no measurable serum verapamil, but one of these had detectable levels of metabolites. Such patients may represent subgroups of fast metabolizers or non-absorbers. Measurements of the metabolites nor-verapamil, D 620 and D 617 indicated saturation of the first-pass metabolism. In conclusion, therapeutic drug monitoring is not indicated during routine verapamil treatment, whereas single measurements of verapamil may be warranted in patients not responding to treatment in order to identify fast metabolizers or non-absorbers.
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Affiliation(s)
- D Husum
- Department of Cardiology, University of Copenhagen, Hvidovre Hospital, Denmark
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10
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Abstract
The pathophysiologic changes occurring in cardiovascular disease can affect the kinetics of drugs in several different ways. The present review examines these modifications and the underlying mechanisms. The kinetics of specific agents, such as antiarrhythmic, antihypertensive, cardiotonic, and other drugs are considered, and the clinical implications are outlined. The clinician should be aware of these modifications, because they require an adjustment of the dosage regimen. A rational basis for a correct therapeutic choice can be provided by adequate knowledge of these modifications.
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Affiliation(s)
- V Rodighiero
- Department of Pharmacology, University of Padova, Italy
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11
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McTavish D, Sorkin EM. Verapamil. An updated review of its pharmacodynamic and pharmacokinetic properties, and therapeutic use in hypertension. Drugs 1989; 38:19-76. [PMID: 2670511 DOI: 10.2165/00003495-198938010-00003] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Although verapamil is a well-established treatment for angina, cardiac arrhythmias and cardiomyopathies, this review reflects current interest in calcium antagonists as anti-hypertensive agents by focusing on the role of verapamil in hypertension. Verapamil is a phenylalkylamine derivative which antagonises calcium influx through the slow channels of vascular smooth muscle and cardiac cell membranes. By reducing intracellular free calcium concentrations, verapamil causes coronary and peripheral vasodilation and depresses myocardial contractility and electrical activity in the atrioventricular and sinoatrial nodes. Verapamil is well suited for the management of essential hypertension since it produces generalised systemic vasodilation resulting in a marked reduction in systemic vascular resistance and, consequently, blood pressure. Evidence from clinical studies supports the role of oral verapamil as an effective and well-tolerated first-line treatment for the management of patients with mild to moderate essential hypertension. Clinical studies have shown that verapamil is more effective the higher the pretreatment blood pressure and some authors have found a more pronounced antihypertensive effect in older patients or in patients with low plasma renin activity. Sustained release verapamil formulations are available for oral administration which, as a single daily dose, are as effective in lowering blood pressure over 24 hours as equivalent doses of conventional verapamil formulations given 3 times daily. As a first-line antihypertensive agent, oral verapamil is equivalent to several other calcium antagonists, beta-blockers, diuretics, angiotensin-converting enzyme (ACE) inhibitors and other vasodilators, and is not associated with many of the common adverse effects of these treatments. Verapamil may be preferred as an alternative first-line antihypertensive treatment to diuretics in elderly patients because it has similar efficacy in these patients without causing the adverse effects commonly linked with diuretic treatment. Furthermore, because verapamil does not cause bronchoconstriction, it may be used in preference to beta-blockers in patients with asthma or chronic obstructive airway disease. Reflex tachycardia, orthostatic hypotension or development of tolerance is not evident following verapamil administration. As a second- or third-line treatment for patients refractory to established antihypertensive regimens, verapamil produces marked blood pressure reductions when combined with diuretics and/or ACE inhibitors, beta-blockers and vasodilators such as prazosin.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- D McTavish
- ADIS Drug Information Services, Auckland, New Zealand
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12
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Carosella L, Menichelli P, Alimenti M, Zuccala G, Gemma A, Cocchi A, Carbonin PU. Verapamil disposition and cardiovascular effects in elderly patients after single intravenous and oral doses. Cardiovasc Drugs Ther 1989; 3:417-25. [PMID: 2487538 DOI: 10.1007/bf01858113] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Pharmacokinetics and pharmacodynamics of verapamil were studied in 11 elderly subjects (age = 79.67 +/- 4.74 years) and in 11 middle-aged subjects (age = 45 +/- 11.37 years) following intravenous (IV), single oral, and long-term oral administration. Plasma verapamil concentrations were determined using high-pressure liquid chromatography (HPLC). Twenty-four hour dynamic Holter electrocardiographic (ECG) recordings were employed to study heart rate (HR) and P-R interval. No difference in plasma half-life, distribution volume, body clearance, and area under the curve (AUC) was observed between the two groups after IV and oral verapamil administration. Blood pressure (BP) and HR were significantly reduced after verapamil IV administration in the elderly group only (p less than 0.05, p less than 0.01, respectively). After single and long-term oral administration, variable HR and BP responses were observed in both groups. The P-R prolongation following both IV and single oral doses exhibited a delay with respect to the peak plasma concentration, inducing a definite hysteresis loop. The slope of P-R variations (using a linear pharmacodynamic model) was greater in the elderly both after IV and single oral verapamil administration, but statistical significance was obtained only after the single oral dose (p less than 0.05). In the elderly group, after long-term oral administration, there was a significant prolongation of the P-R interval (p less than 0.0001) with respect to the corresponding time point of the 24-hour predrug period. Such variations in pharmacodynamic parameters in the elderly did not, however, cause any clinical problem.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L Carosella
- Divisione di Gerontologia, Universita Cattolica del Sacro Cuore, Rome, Italy
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13
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Andersson BS, Beran M, Stuckey SE, McCredie KB, Mavligit GM. Sensitivity and resistance to chemotherapy in acute leukemia: correlation with in vitro drug uptake and lack of potentiation by verapamil. MEDICAL ONCOLOGY AND TUMOR PHARMACOTHERAPY 1987; 4:17-21. [PMID: 3600053 DOI: 10.1007/bf02934930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The calcium channel blocker verapamil has been reported to circumvent acquired resistance to different antitumor agents in tumor cell lines in vitro. We studied its effect on in vitro uptake of m-AMSA and adriamycin in fresh leukemic cells from 11 leukemia patients. Six previously untreated patients were sensitive to m-AMSA (obtained remission). Four were clinically resistant to m-AMSA, and two of these also to adriamycin. Leukemic cells were incubated in pharmacological doses of 14C-adriamycin and 14C-m-AMSA for up to 2 h. Samples were supplemented with verapamil (750 ng ml-1) 30 min prior to the addition of m-AMSA or adriamycin. Drug uptake was measured at 15 min intervals up to 2 h and drug retention was measured during 30 min after the end of incubation, following washing and resuspension in fresh medium without cytotoxic drugs. Adriamycin uptake was the same irrespective of verapamil in all four cell samples, two of which were derived from patients resistant to adriamycin. The cellular m-AMSA uptake was higher in cells from clinically sensitive than from resistant patients (510 +/- 155 fg cell-1 vs 275 +/- 125 fg cell-1; P less than 0.01). Retention of m-AMSA 30 min after incubation was higher in cells from sensitive compared to resistant patients (187 +/- 78 vs 25 +/- 7; P less than 0.05). Our data suggest: (1) in vitro uptake greater than or equal to 350 fg cell-1 and subsequent retention greater than 75 fg cell-1 correlate to clinical sensitivity to the drug; and (2) neither m-AMSA nor adriamycin uptake could be significantly increased by verapamil.
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14
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Dunn J. Controlled-release formulations of propranolol and verapamil. J Clin Pharmacol 1987; 27:22-31. [PMID: 3316302 DOI: 10.1177/009127008702700104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The in vitro and clinical behavior of new controlled-release formulations of propranolol and verapamil are reviewed. In vitro dissolution studies have proved to be of little value in determining the clinical activity of these new dosage forms. There is a difference between the blood levels found with the new formulations and those of the reference products. The once-daily verapamil product was evaluated in black hypertensive patients with promising results and suggests that this dosage form of verapamil may be successful as monotherapy for treating this patient population.
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Affiliation(s)
- J Dunn
- Verex Laboratories, Englewood, Colorado 80112
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15
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Mølgaard H, Bjerregaard P, Jørgensen HS, Klitgaard NA. 24-hour antiarrhythmic effect of conventional and slow-release verapamil in chronic atrial fibrillation. Eur J Clin Pharmacol 1987; 33:447-53. [PMID: 3428338 DOI: 10.1007/bf00544233] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Twenty-four-hour heart rate control by verapamil given as conventional tablets t.d.s., or as a new slow release formulation once daily, has been compared in an open cross-over trial. Eight patients with chronic atrial fibrillation and one with chronic atrial flutter were studied outside hospital. Trough serum concentration of verapamil did not differ during the two dosage regimens (59 ng/ml - conventional formulation and 49.3 ng/ml - slow release tablet). The average serum concentration of digoxin in the patients was not changed. Compared to the control phase, both dosage regimens significantly and equally reduced individual and average heart rates throughout the entire 24-h period. A positive correlation between the serum concentration of verapamil and the relative increase in average R-R interval was demonstrated. It is concluded that dosage t.d.s. with conventional tablets of verapamil or once daily with the slow release formulation gave the same antiarrhythmic efficacy over 24 h, and was associated with equal trough serum concentrations of verapamil.
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Affiliation(s)
- H Mølgaard
- Medical Department, Aarhus University Hospital, Denmark
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16
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Anderson P, Bondesson U, Mattiasson I, Johansson BW. Verapamil and norverapamil in plasma and breast milk during breast feeding. Eur J Clin Pharmacol 1987; 31:625-7. [PMID: 3830249 DOI: 10.1007/bf00606644] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The concentrations of verapamil and norverapamil have been measured in milk and plasma samples from a 32 year-old woman treated with verapamil 80 mg tds while breast-feeding her child. The average steady-state concentrations of verapamil and noverapamil in milk were, respectively, 60% and 16% of the concentrations in plasma. The breast-fed child received less than 0.01% of the dose of verapamil given to the mother. No verapamil or norverapamil (less than 1 ng/ml) could be detected in the plasma from the child.
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17
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Anderson P, Bondesson U, de Faire U. Pharmacokinetics of verapamil in patients with hypertension. Eur J Clin Pharmacol 1986; 31:155-63. [PMID: 3803414 DOI: 10.1007/bf00606652] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Twelve hypertensive patients (WHO Stage I-II) were given oral verapamil (Isoptin) b.d. or t.d.s. as long-term treatment. The pharmacokinetics of verapamil and norverapamil were studied both after single and b.d. and t.d.s. doses of verapamil 240, 360 or 480 mg daily adjusted according to the blood pressure response. The apparent oral clearance of verapamil was decreased after both the twice and thrice daily dosage regimens (1.38 and 1.841/min, respectively) as compared to the single dose (4.391/min). The plasma half-life of verapamil was increased from 3.34 h (single dose) to 4.65 h (b.i.d.). Decreased elimination of norverapamil was also found after multiple doses of verapamil, as shown by an increase in the adjusted AUC of norverapamil (adjusted to a verapamil dose of 80 mg), namely from 574.9 h X ng X ml-1 (single dose) to 1172 h X ng X ml-1 (b.d.) and to 841 h X ng X ml-1 (t.d.s.). The plasma half-life of norverapamil increase from 5.68 h to 7.34 h during twice daily dosing. During thrice daily verapamil, no increase in plasma half-life was found either for verapamil or norverapamil, probably due to the relatively short sampling time (6 h). The plasma concentration of verapamil and the reduction in supine systolic and diastolic blood pressure were correlated. The mean decrease in supine systolic blood pressure was 5.8 mm Hg per 100 ng verapamil/ml plasma, and for diastolic pressure 2.9 mm Hg per 100 ng verapamil/ml plasma.(ABSTRACT TRUNCATED AT 250 WORDS)
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18
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Abstract
Bepridil hydrochloride differs from the other calcium antagonists in structure as well as in several clinical pharmacokinetic characteristics. The drug is completely absorbed from the gastrointestinal tract, but first-pass extraction reduces oral bioavailability to approximately 60%. After single-dose administration, the elimination half-life of bepridil averages 33 +/- 15 hours. However, upon multiple dosing, a half-life of 42 +/- 12 hours is found. As with verapamil and diltiazem, bepridil clearance is decreased after multiple dosing. Bepridil is completely metabolized, presumably by hepatic oxidative processes. A total of 17 metabolites have been identified, but the contribution of any of these metabolites to observed clinical response is currently unclear. The free fraction of bepridil in plasma is low, averaging only 0.23%. Despite this high protein binding, in vitro studies indicate that the potential for drug-to-drug interactions based on displacement of bepridil from its binding sites is low. Bepridil follows a linear dose/plasma concentration relation after single and multiple doses of the drug in both healthy volunteers and patients with angina. However, mean steady-state plasma bepridil concentrations are higher in patients, indicating a greater average decreased clearance. Food does not interfere with bepridil absorption. At this time, no significant pharmacokinetic interactions between bepridil and digoxin have been detected.
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Abstract
Effective use of drugs in therapy depends not only on clinical acumen but also on the availability of relevant pharmacokinetic and pharmacodynamic data. Such information assists in development of safe dosing regimens, prediction of abnormal handling of drugs in states of disease and disorder and anticipation of drug interactions. For the calcium-entry blocking agents now available in the United States (verapamil, nifedipine and diltiazem), these data appeared well after clinical patterns of use evolved. Nonetheless, their relevance continues to be demonstrated by the dependence of each agent on intact liver blood flow and function for normal rates of elimination; by the nonlinear kinetic characteristics for verapamil and diltiazem (and probably for nifedipine, as well) and the derivative implications for decreased dosing frequency requirements; and by observations now appearing on the relation between plasma drug levels and drug effects, both therapeutic and toxic. Such data are discussed herein, with emphasis on those aspects that impact on the clinical use of the calcium-entry antagonists.
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Vogelgesang B, Echizen H, Schmidt E, Eichelbaum M. Stereoselective first-pass metabolism of highly cleared drugs: studies of the bioavailability of L- and D-verapamil examined with a stable isotope technique. Br J Clin Pharmacol 1984; 18:733-40. [PMID: 6508982 PMCID: PMC1463564 DOI: 10.1111/j.1365-2125.1984.tb02536.x] [Citation(s) in RCA: 144] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The pharmacokinetics of dextro(+)- and levo(-)-verapamil were studied in five healthy volunteers following oral administration of pseudoracemic verapamil containing equal amounts of unlabelled (-)- and dideuterated (+)-isomer. (+)-verapamil exhibited approximately five times greater Cmax (+): 240 +/- 81.1 ng/ml, (-): 46.1 +/- 15.7 ng/ml, P less than 0.0001) and AUC than (-)-verapamil. The apparent oral clearance (CLo) for (+)-verapamil was significantly smaller than that for (-)-verapamil (+): 1.72 +/- 0.57 l/min, (-): 7.46 +/- 2.16 l/min, P less than 0.001). The bioavailability of (+)-verapamil (50%) was 2.5 times greater than that of (-)-verapamil (20%), P less than 0.005). Thus following oral administration verapamil exhibited a stereoselective first-pass metabolism. Neither tmax nor the elimination t1/2,z were different between the isomers. The elimination of t1/2,z for each verapamil isomer obtained following oral administration (+): 4.03 h, (-): 5.38 h) were similar to those previously obtained following intravenous administration (+): 4.15 h, (-): 5.38 h, respectively. Whereas the (+)- to (-)-verapamil plasma concentration ratio following oral administration was 4.92 +/- 0.48, the ratio following i.v. administration was approximately 2. (-)-verapamil has been demonstrated to possess 8 to 10 times more potent negative dromotropic effect on AV conduction than (+)-verapamil. Therefore, following oral administration the same concentration of plasma verapamil consisting of a two to three times smaller proportion of the more potent (-)-isomer appeared to be less potent than that following i.v. administration with regard to the negative dromotropic effects on the AV conduction.
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Eichelbaum M, Mikus G, Vogelgesang B. Pharmacokinetics of (+)-, (-)- and (+/-)-verapamil after intravenous administration. Br J Clin Pharmacol 1984; 17:453-8. [PMID: 6721991 PMCID: PMC1463390 DOI: 10.1111/j.1365-2125.1984.tb02371.x] [Citation(s) in RCA: 154] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The pharmacokinetics of (+)-, (-)-, and (+/-)-verapamil were studied in five healthy volunteers following i.v. administration of the drugs. Pronounced differences of the various pharmacokinetic parameters were observed between the (-)- and (+)-isomers. The values for CL, V, Vz, and Vss of the (-)-isomer were substantially higher as compared to the (+)-isomer, whereas terminal t 1/ 2Z was nearly identical for both isomers. No dose dependency of the pharmacokinetics could be observed in two subjects who received 5, 7.5 and 10 mg of (-)- and 5, 25 and 50 mg of (+)-verapamil. Protein binding for the two isomers was also different. The fu of (-)- (0.11) was almost twice as much as that of (+)-verapamil (0.064). Pharmacokinetic parameters of (+/-)-verapamil, which was administered to three subjects who had received (+)- and (-)-verapamil, were very similar to the averaged values of the isomers given separately. Due to the higher CL of (-)-verapamil the extraction ratio of the (-)-isomer is substantially higher. Thus, it can be anticipated that following oral administration of racemic verapamil bioavailability of (-)-verapamil will be substantially less. Since the (-)-isomer is more potent than the (+)-isomer, the present findings could explain the reported differences in the concentration-effect relationship after i.v. and oral administration of racemic verapamil.
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Abstract
Verapamil is widely used in the treatment of supraventricular tachyarrhythmias as well as for hypertension and control of symptoms in angina pectoris. Unlike other calcium antagonists, detailed pharmacokinetic data are available for verapamil. Plasma concentrations of verapamil appear to correlate with both electrophysiological and haemodynamic activity after either intravenous or oral drug administration, although considerable intra- and intersubject variation has been found in the intensity of pharmacological effects resulting at specific plasma drug levels. Verapamil is widely distributed throughout body tissues; animal studies suggest that drug distribution to target organs and tissues is different with parenteral administration from that found after oral administration. The drug is eliminated by hepatic metabolism, with excretion of inactive products in the urine and/or faeces. An N-demethylated metabolite, norverapamil, has been shown to have a fraction of the vasodilator effect of the parent compound in in vitro studies. After intravenous administration, the systemic clearance of verapamil appears to approach liver blood flow. The high hepatic extraction results in low systemic bioavailability (20%) after oral drug administration. Multicompartmental kinetics are observed after single doses; accumulation occurs during multiple-dose oral administration with an associated decrease in apparent oral clearance. Norverapamil plasma concentrations approximate those of verapamil following single or multiple oral doses of the parent drug. Because of the complex pharmacokinetics associated with multiple-dose administration and the variation in individual patient responsiveness to the drug, 'standard' dosing recommendations are difficult to determine; use of verapamil must be titrated to a clinical end-point. Further, the potential for alteration in verapamil's disposition by the presence of hepatic dysfunction or cardiovascular disorders which result in altered hepatic blood flow is only now becoming apparent. A potentially toxic interaction has been reported between verapamil and digoxin, in which renal excretion of the glycoside is impaired, but the true clinical significance of this remains debatable. Combination therapy with verapamil and beta-adrenoceptor blocking compounds has been advocated by some investigators, but may be hazardous because of the additive negative inotropic and chronotropic effects inherent in both agents.
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