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Enalaprilat in acute myocardial infarction: tolerability and effects on the renin-angiotensin system
A Sigurdsson1, P Held, G Andersson
1Department of Medicine, Ostra Hospital, University of Göteborg, Sweden.
Insights
Early administration of intravenous enalaprilat in acute myocardial infarction patients showed good tolerability. This angiotensin converting enzyme inhibitor effectively suppressed plasma activity without significant hormonal changes.
Area of Science:
- Cardiology
- Pharmacology
Background:
- Acute myocardial infarction (AMI) is a leading cause of cardiovascular mortality.
- Early intervention is crucial to limit infarct size and improve outcomes.
- Angiotensin converting enzyme (ACE) inhibitors have demonstrated benefits in heart failure and post-MI patients.
Purpose of the Study:
- To evaluate the safety and tolerability of early intravenous enalaprilat administration in patients with acute myocardial infarction.
- To assess the impact of enalaprilat on hemodynamic parameters and neurohormonal markers.
Main Methods:
- A study involving 48 patients with AMI treated within 24 hours of symptom onset.
- Patients received intravenous enalaprilat via bolus or infusion, with concomitant standard therapies.
- Hemodynamic parameters and plasma levels of angiotensin converting enzyme (ACE), angiotensin II, renin activity, and atrial natriuretic peptide were monitored.
Main Results:
- Intravenous enalaprilat was well-tolerated in selected AMI patients, with no symptomatic hypotensive reactions.
- A significant decrease in blood pressure was observed, with careful titration preventing severe hypotension.
- Complete suppression of plasma ACE activity was achieved within 30 minutes, with no significant changes in other measured neurohormonal markers.
Conclusions:
- Intravenous enalaprilat, followed by oral enalapril, is a safe and well-tolerated addition to conventional therapy in the early phase of acute myocardial infarction.
- Careful titration of enalaprilat is recommended to manage blood pressure effectively.
- Early ACE inhibition may play a role in the management of acute myocardial infarction.
Abstract:
We treated 48 patients with intravenous enalaprilat within 24 hours from the onset of acute myocardial infarction. Concomitant therapy included thrombolytic treatment (29), intravenous metoprolol (34), intravenous nitroglycerin (16) and intravenous furosemide (15). The first 40 patients included had systolic blood pressure at baseline greater than or equal to 110 mmHg. Intravenous bolus injections of 0.2-1.2 mg (mean 1.0 mg) enalaprilat in one hour were given to 20 patients and an intravenous infusion of 1 mg over two hours was administered to another 20 patients, as well as to a separate group of 8 patients with systolic blood pressure between 100-109 mmHg at baseline. The infusion was stopped in five cases when the systolic blood pressure fell below 100 and 90 mmHg, respectively, in the two infusion groups. No hypotensive reactions were symptomatic. Blood pressure decreased from a mean of 134/82, 131/79 and 106/72 mmHg to a minimum of 117/71, 118/73 and 97/63 mmHg, respectively, in the three groups. Almost complete suppression of plasma angiotensin converting enzyme activity was achieved within 30 minutes. No significant changes were found in plasma levels of angiotensin II, renin activity or atrial natriuretic peptide between baseline and 24 hours. Treatment was continued with oral enalapril 2.5-10 mg/day, which was generally well tolerated. We conclude that intravenous and oral enalapril added to conventional therapy in the early phase of acute myocardial infarction is well tolerated in selected patients, but should be carefully titrated.