A clinical pharmacological study of nifedipine and lisinopril alone and in combination.

A double-blind, randomised, placebo-controlled, latin square design study of nifedipine, 20 mg, and lisinopril, 20 mg, alone and in combination was performed in 12 healthy male volunteers. Blood pressure, heart rate, lisinopril and nifedipine levels, plasma catecholamines, renin, aldosterone, and angiotensin converting enzyme activity were measured for 96 h after each acute dose. Both drugs lowered blood pressure (p less than 0.001), but the combination showed only additive effects. Heart rate rose over the first 4 h following the combination. Side effects were also additive. There was no effect of nifedipine on plasma ACE, renin, or aldosterone and no effect of either drug on plasma catecholamines. The pharmacokinetics of both drugs were unaltered in combination. Thus, nifedipine and lisinopril have additive dynamic effects with no pharmacokinetic interaction.