A clinical trial was performed to evaluate the antihypertensive efficacy and side effects of amlodipine, a new long-action calcium antagonist, in patients with mild to moderate essential hypertension as measured by 24-h ambulatory blood pressure monitoring.

1) The study patients consisted of 4 men and 6 women, and the mean age was 51 years. Amlodipine monotherapy(5~10mg) was continued for 4 weeks, and blood pressure was measured by 24-h ambulatory blood pressure monitoring. 2) A smooth and sustained lowering of blood pressure was clearly achieved without affecting the circadian rhythm throughout dosing interval. The mean-pressure drop was 21.2/13.7mmHg after 4 weeks of amlodipine monotherapy. 3) The ambulatory pulse rate revealed virtually identical average hourly pulses during the recording period before and after amlodipine treatment. 4) All of the laboratory parameters including blood chemistry, glucose, lipid and electrolytes did not change significantly after 4 weeks of amlodipine monotherapy. 5) Amlodipine therapy resulted in minimal side effects that were well tolerated.

Once-daily amlodipine monotherapy with 5 to 10mg in controlling blood pressure throughout each 24-h cycle is effective and well tolerated in the patients with mild to moderate essential hypertension.