Start of therapy with the angiotensin II antagonist losartan after immediate switch from pretreatment with an ACE inhibitor.

AIMS: To evaluate initial blood pressure effects of the angiotensin II antagonist losartan (L) immediately after switching from an ACE inhibitor (captopril, C).

METHODS

Two-phase multicentre randomized study in 177 outpatients with mild to moderate essential hypertension. For 6 weeks all patients received 25 mg C twice daily. Then they were randomized double-blind to switch for another 6 weeks to 50 mg L once daily (n=110) or to maintain C (n=55). On the first day of the switch they underwent ambulatory blood pressure measurement (ABPM).

RESULTS

Within 12 h of first dose, 31% of patients who switched to L had two consecutive systolic BP readings of 30 mmHg below their individual baseline value compared with 24% of patients who stayed on C. In 3% of patients with L and in 6% of the C patients systolic BP readings less than 100 mmHg were recorded within 12 h of first dose. The differences were not statistically significant. There were no clinical symptoms attributable to initial hypotension. During the 6 weeks double-blind therapy, 9% of L patients experienced at least one adverse event, compared with 16% of patients with C.

CONCLUSIONS

In this study the angiotensin II antagonist losartan was effective and generally well tolerated when administered immediately after pretreatment with an ACE inhibitor.