BACKGROUND AND OBJECTIVES: This study was designed to evaluate the appropriate dose and dose-dependent effect of benidipine hydrochloride, a Ca+ +/- channel blocker, in patients with mild-moderate essential hypertension. Material and MethodsBenidipine was administered in 2 mg, 4 mg and 8 mg once daily with 1 month interval in 41 hypertensive patients with diastolic blood pressure over 90 mmHg and systolic blood pressure from 140 to 210 mmHg. Blood pressure, heart rate, subjective symptoms and adverse effects were checked every 4 weeks after benidipine administration. Laboratory examinations were performed before and after benidipine administration. RESULTS: The dose-dependent, antihypertensive effect of benidipine was evaluated in 41 patients. The blood pressure significantly reduced from 166+/-15 mmHg/103+/-7 mmHg to 13815 mmHg/88+/-11 mmHg at 12 weeks administration of benidipine and overall effective rate was 95%. The systolic and diastolic blood pressure was reduced significantly in proportion to dose of benidipine (p<0.0001). Antihypertensive effect was prominent at 4mg of benidipine. The heart rate was not affected by benidipine. No significant laboratory changes were observed. CONCLUSION: Benidipine has a dose-dependent effect in the treatment of mild-moderate hypertension, and the dosage to be needed may be 4mg or more for sufficient antihypertensive effect.