Comparison of Efficacy and Tolerability of Spirapril and Nitrendipine in Arterial Hypertension

Summary

In a double-blind randomised parallel group trial a new angiotensin-converting enzyme (ACE) inhibitor, Spirapril, was compared to nitrendipine in 266 patients with hypertension (diastolic blood pressure 95 to 119mm Hg). Blood pressure was measured 24 hours after administration, and dose titration was performed every fourth week to achieve a diastolic blood pressure ⩽ 90mm Hg. After 4 weeks’ monotherapy with either nitrendipine 20mg once daily or Spirapril 12mg once daily, the dose was increased to 40mg once daily and 24mg once daily, respectively, if goal blood pressure had not been achieved. After 8 weeks of monotherapy hydrochlorothiazide 12.5mg once daily could be added.

Both treatments had a low response rate and the reduction in blood pressure was lower than expected. No significant difference was found in the reductions in blood pressures between the 2 treatment regimens. The effect of adding hydrochlorothiazide to Spirapril was as expected, while the combination with nitrendipine only had a marginal extra effect on blood pressure. Significantly more patients in the nitrendipine group were withdrawn due to adverse events (27%) than in the Spirapril group (7%).

In conclusion, at the dosages used, nitrendipine and Spirapril lower blood pressure to the same degree, but nitrendipine produces more adverse events. The addition of hydrochlorothiazide to nitrendipine cannot be recommended.