Comparative effects of FR 34235, a new slow channel calcium blocker, and nifedipine on hemodynamics and myocardial oxygen consumption in the anesthetized dog

1. 1. Five doses of two dihydropyridine calcium antagonists, FR 34235 and nifedipine, were given intravenously to anesthetized dogs to determine effects on hemodynamics and myocardial oxygen balance. 2. 2. Both agents produced dose-related decreases in mean arterial blood pressure and tension time index with little effect on heart rate, d P/d t or myocardial contractile force except at high doses where small decreases were observed. 3. 3. Coronary blood flow increased markedly in the presence of both agents with a maximum increase observed at doses of 10 and 30 μg/kg for FR 34235 and nifedipine, respectively. 4. 4. Both compounds decreased myocardial oxygen extraction at all doses and reduced myocardial oxygen consumption at higher doses. 5. 5. These results indicate that FR 34235, a new slow channel calcium blocker, is a potent coronary vasodilator. In addition, this compound possesses oxygen-sparing activity at higher doses.