Trial of slow release diltiazem for essential hypertension in general practice.

In New Zealand diltiazem has been approved since 1984 for the treatment of angina pectoris and was available only as short acting tablets. This study was a trial of a slow release formulation in the treatment of hypertension. A single blind placebo controlled study was undertaken on 24 patients in general practice using a once daily dose with a maximum of 360 mg. The mean fall in resting supine diastolic blood pressure was 17.3 mmHg, 95% CI 14.4 to 20.2; t = 12.2, df = 23, p = 0.0001. Twelve patients (50%) achieved a fall in diastolic pressure to 90 mmHg or less with the minimum dose (120 mg) while 19 patients (79%) achieved this level with up to 360 mg daily and 22 patients (92%) had a fall of diastolic pressure of 10 mmHg or more. One patient was withdrawn because of a rash. Other adverse reactions were mild and usually tolerable.