Long-term effect of tiapamil in essential hypertension.

To evaluate the long-term effect of tiapamil, a new calcium antagonist, in hypertension, 20 adult patients suffering from mild to moderate hypertension were entered into a 58-week open study. In 10 patients, blood pressure returned to normal within 1-6 weeks with a daily dose of 600-900 mg tiapamil. In the remaining 10 patients, the blood pressure became normal after 8-28 weeks with a daily dose of 900-1,200 mg tiapamil. The more severe the hypertension, the higher the dose needed and the longer the time required for the blood pressure to return to normal. The overall results at the end of the 58-week treatment showed a significant decrease of the blood pressure to 142 (+/- 9)/88 (+/- 4) mmHg from a before treatment average of 166 (+/- 16)/105 (+/- 7) (p less than 0.001). There was no marked difference in the blood pressure between supine and sitting positions before or after treatment. Side effects were mild and self-limiting, with no patient being dropped from the study. Electrocardiogram (ECG) and laboratory values were not affected during the treatment with the exception of a moderate decrease in the blood glucose. Neither plasma renin activity, nor aldosterone concentration, nor serum cholesterol or triglyceride levels were altered during tiapamil administration. Tiapamil appears to be an effective and well-tolerated drug for use in mild to moderately severe hypertension.