Regional vasodilating and cardiac effects of nicardipine in anaesthetized open chest dog.

In this study the effects of intravenous nicardipine on the cardiovascular system in anaesthetized open chest dogs were assessed. In the dose range of 3-30 nmol/kg it induced a dose-dependent and long lasting reduction of the vertebral, coronary and femoral vascular resistance. Nicardipine proved to be equipotent, but longer lasting than nifedipine, and about 10 and 100 times more potent than verapamil and papaverine respectively. Unlike papaverine, calcium entry blockers caused a preferential vasodilation of the vertebral and coronary arteries. Hypotension and a reduction of LVSP and dP/dt appeared only at the highest dose tested. However, for both dihydropyridine derivatives, in contrast to verapamil, the cardiodepressant effects were short-lived and resulted less marked for nicardipine than for nifedipine.