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Postabsorption concentration peaks with brand-name and generic verapamil: a double-blind, crossover study in elderly hypertensive patients.

Abstract：

:The pharmacokinetic actions, bioequivalence, and cardiovascular effects of two verapamil products were studied in a randomized, double-blind, crossover study in eight elderly hypertensive patients (median age, 69.5 years; range, 60-79 years) given brand-name or generic immediate-release verapamil in 120-mg twice-daily doses for 14 days. Blood pressures, heart rates, P-R intervals; and serum concentrations of R-/S-verapamil and norverapamil were measured multiple times in patients during the last day of each therapy. Median blood pressure decreased more with generic verapamil than with the brand-name drug, with the largest difference occurring at 0.5 hours (137/74 mmHg versus 144.5/80.5 mmHg; P = 0.05 and 0.091, respectively). Pharmacokinetic parameters were not different for the two products (P < 0.01). However, the generic product, compared with the brand-name drug, had mean area under the concentration-time curve (time 0 to 12 hours) ratios (90% CI) of 1.09 (0.78-1.52), 1.16 (0.87-1.55) and 1.11 (0.81-1.52) for R-, S-, and total verapamil. Seventy concentration peaks (31 with the brand-name drug, 39 with the generic drug) appeared between 8 and 24 hours. Median percentages of increase of these peaks, compared with those of previous concentrations, were 48.3% and 36.3% for brand-name and generic drugs, respectively. Fifty of the 70 peaks (71%) were associated with a stereospecific concentration peak of norverapamil and, temporally, with meals. Our findings suggest that whereas the two verapamil products may not be bioequivalent by Food and Drug Administration criteria, the observed differences in effects were not clinically significant in this elderly population. Multiple concentration peaks after absorption were observed in all patients with both verapamil products and were perhaps related to enterohepatic recirculation.

journal_name

J Clin Pharmacol

journal_title

Journal of clinical pharmacology

authors

Saseen JJ,Porter JA,Barnette DJ,Bauman JL,Zajac EJ Jr,Carter BL

doi

10.1002/j.1552-4604.1997.tb04331.x

subject

Has Abstract

pub_date

1997-06-01 00:00:00

pages

526-34

issue

eissn

0091-2700

issn

1552-4604

journal_volume

pub_type

临床试验,杂志文章,随机对照试验

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Postabsorption concentration peaks with brand-name and generic verapamil: a double-blind, crossover study in elderly hypertensive patients.