Cardiovascular effects of a single high dose of dilazep by oral route.

The acute hemodynamic effects on the coronary and systemic arteries of a single high dose of dilazep given orally (200-400 mg; 3-5 mg/kg) were studied in 25 anginal patients who, for diagnostic reasons, underwent cardiac catheterization and coronary angiography. From 20 to 30 min after drug administration, systemic vascular resistance (1666 +/- 348 to 1367 +/- 312 dyn X sec X cm-5, P less than 0.05) and left ventricular end-diastolic pressure (16.5 +/- 5 to 12 +/- 4.4 mm Hg, P less than 0.01) decreased significantly. The heart rate rose from 74 +/- 10 to 84 +/- 12 beats/min (P less than 0.05), while the cardiac index, dp/dt max and pulmonary arteriolar resistance did not change significantly. Concomitantly, coronary blood flow significantly increased, coronary resistance was reduced by 42% (P less than 0.01) while myocardial oxygen consumption was unchanged. The increase in mean coronary arterial diameter was by 22-25%. It is concluded that dilazep has a prompt and potent vasodilating action even after oral administration. The drug is therefore useful in the chronic treatment of ischemic heart disease.