ACUTE PHARMACOKINETIC AND HEMODYNAMIC-EFFECTS OF INTRAVENOUS BOLUS DOSING OF NICARDIPINE

The antihypertensive effects, duration of action, and pharmacokinetics of intravenous bolus doses of nicardipine were investigated in a series of patients with mild-to-moderate hypertension. Patients with a supine diastolic blood pressure between 95 and 114 mm Hg and a heart rate<90 beats/min who received no other antihypertensive medications were included in the study. On separate study days, single intravenous bolus doses of 0.125, 0.25, 0.5, 1, 3, 5, and 7 mg of nicardipine were administered over a 2-minute period. Blood pressure and heart rate were measured for 6 hours after an intravenous bolus of nicardipine was given, and serum nicardipine levels were measured throughout the study. Although the antihypertensive effect occurred immediately during the bolus infusion, peak average decreases in systolic and diastolic pressure ranged from 20 to 25 and 15 to 44 mm Hg, respectively, and occurred 2.5±0.6 minutes after infusion. Heart rate increased by 12 to 40 beats/min during the peak effect. The mean duration of action after an intravenous bolus dose was 24±5 minutes. A dose-response relationship was observed, as both nicardipine dosage and plasma nicardipine concentration correlated with reduction in blood pressure. These data indicate that bolus administration of nicardipine may provide a practical approach for the rapid parenteral treatment of hypertensive states. © 1990.