Effects of oral lacidipine on cardiopulmonary function at rest and during exercise in normal subjects.
A randomized, double-blind, crossover, placebo-controlled study was carried out to evaluate the effects of a single oral 4-mg dose of lacidipine vs. placebo on cardiopulmonary circulation at rest and during exercise. Twelve healthy volunteers were randomized to receive either placebo or 4 mg of lacidipine once daily for 2 days, followed by a 3-day washout period, after which they received alternate treatment. Patients were assessed before and at 60, 90, and 180 min after dosing. At 120 min, a maximum exercise test with a treadmill was performed according to the Bruce protocol. No relevant changes with placebo or lacidipine were observed in the respiratory function tests whereas 4 mg of lacidipine increased pulmonary effective blood flow (Qp. eff.) and stroke volume index (SVI) at 60 min, reaching a peak at 90 min; at 180 min, these effects, although diminished, were still present. The arteriovenous oxygen difference [C(a-v)O2] decreased, but reverted to normal values by 180 min. No differences in maximum attained Qp. eff. and oxygen consumption (VO2) during exercise were observed. Only the heart rate was higher both before and after treatment with lacidipine. Lacidipine increased Qp. eff. in these normal subjects without relevant effects on respiratory function. Performance on exercise testing after dosing was normal, although drug-induced vasodilation was present.