First dose hypotension after angiotensin converting enzyme inhibitor captopril and angiotensin II blocker losartan in patients with acute myocardial infarction

Background: First dose hypotension after the administration of an angiotensin-converting enzyme inhibitor in patients with acute myocardial infarction is one of the most important adverse events of this type of treatment. There is no information about first dose hypotension after angiotensin type 1-receptor blocker in this type of patient. Aim: To compare the first dose responses to low dose captopril and losartan in patients with acute myocardial infarction. Methods: Single blind, randomised, multicentric, prospective study. Patients (n=320) with confirmed acute myocardial infarction, age >18 years, treated by direct percutaneous transluminal coronary angioplasty, thrombolysis and/or heparin, were randomised to receive a single dose of 6.25–12.5 mg captopril or 12.5–25 mg losartan within 24 h of hospital admission. Baseline laboratory and clinical examinations were performed before entering the study. Blood pressure monitoring started at hospital admission and continued for at least 8 h after the medication (second dose of captopril was given after 8 h). Results: The maximal blood pressure fall appeared about 1 h after the first dose of captopril and 3.5 h after the first dose of losartan. Patients in the captopril group had significantly higher incidence of asymptomatic hypotension (38%) than patients treated with losartan (24%) (P<0.001). No difference in hypotension requiring a change in medication was observed. Conclusion: Low dose of losartan is safe for initiating therapy in patients with acute myocardial infarction within 24 h of hospital admission.