PHARMACOKINETIC INTERACTION STUDY BETWEEN BENAZEPRIL AND AMLODIPINE IN HEALTHY-SUBJECTS

Pharmacokinetic interaction between benazepril (ACE inhibitor) and aml odipine (calcium channel blocker) was studied in 12 healthy subjects. Single doses of benazepril hydrochloride (10-mg tablet) and amlodipine besylate (tablet equivalent to 5 mg amlodipine) were administered alo ne or in combination according to a three-way, Latin-Square, randomize d crossover design. Serial blood samples were collected following each administration for the determination of benazepril and its active met abolite benazeprilat and amlodipine. The mean values of AUC (0-4 h), C -max and T-max for benazepril given as combination versus given alone were 161 vs 140 ng.h.ml(-1), 168 vs 149 ng.ml(-1), and 0.5 vs 0.6 h. T he mean values of AUC (0-24 h), C-max and T-max for benazeprilat after benazepril given as combination Versus given alone were 1470 vs 1410 ng.h.ml(-1), 292 vs 257 ng.ml(-1), and 1.7 vs 1.5 h. The mean values o f AUC (0-144 h), C-max and T-max for amlodipine given as combination v ersus given alone were 118 vs 114 ng.h.ml(-1), 2.5 vs 2.3 ng.ml(-1), a nd 8.3 vs 9.0 h. The differences in these pharmacokinetic pa rameters between the combination and monotherapy treatments were not statistica lly significant based on ANOVA. The results of this study indicate tha t no pharmacokinetic interaction existed between the two drugs.