Pharmacokinetic and pharmacodynamic data were compared between elderly and young patients with hypertension who received single intravenous doses of amlodipine, a dihydropyridine calcium antagonist, followed by oral administration of amlodipine up to 10 mg once daily for 12 weeks. After intravenous administration, elderly patients had prolonged elimination half-life values (58 +/- 11 vs 42 +/- 8 hr; p < 0.05) caused by decreased clearance (19 +/- 5 vs 7 liters/hr; p < 0.05). Systolic and diastolic blood pressures were significantly decreased from baseline throughout the 3-month treatment period in both groups. After long-term oral administration, elderly and young patients had comparable decreases in mean blood pressure at a given drug plasma concentration. The antihypertensive effect of amlodipine is well correlated with plasma concentration and, at a given concentration, is similar in both elderly and young patients.