Early administration of nifedipine in suspected acute myocardial infarction: The Secondary Prevention Reinfarction Israel Nifedipne Trial 2 study

Background: The administration of nifedipine, 30 mg/d, between 7 and 22 days after hospitalization for an acute myocardial infarction (Secondary Prevention Reinfarction Israel Nifedipine Trial study) showed no effect on subsequent mortality and morbidity. Since a possible inon of benefit was observed in patients with a second- or higher-order infarction, a second trial was conducted with a higher dose (60 mg/d), early administration (usually within 3 hours of hospital admission), and in high-risk patients only. Methods: A total of 1358 men and women with suspected acute myocardial infarction (MI), judged not to require calcium antagonist therapy, were randomized to receive nifedipine, 60 mg/d, or placebo between November 1985 and July 1986. Study medication was discontinued in 352 patients because they did not exhibit study criteria for MI or lacked high-risk criteria, or because they decided to discontinue the study. Thus, the treated highrisk group included 1006 patients, of whom 826 were successfully titrated to the target dose of 60 mg/d and were treated for up to 6 months. Results: In the 1006 patients, mortality was 18.7% among those randomized to nifedipine and 15.6% in the patients randomized to placebo. This reflected an increased mortality of 7.8% as compared with 5.5% during the first 6 days in the nifedipine and placebo groups, respectively (adjusted mortality odds ratio by logistic regression, 1.60; 95% confidence interval, 0.86 to 3.00). Among the 826 patients who continued treatment, mortality was equal in the nifedipine (9.3%) and placebo (9.5%) groups. No differences in the rates of nonfatal MI (5.1% and 4.2% in the nifedipine and placebo groups, respectively), hospitalization due to unstable angina, and frequency of chest pain reported during follow-up were observed. An increased rate of sudden death (4.9%) in the placebo group in comparison with the nifedipine group (2.3%) was not statistically significant on post hoc testing, nor was an effect of nifedipine demonstrable in post hoc analyses by congestive heart failure status of randomized patients. Conclusion: Nifedipine as a prophylactic treatment in patients immediately after acute MI or in survivors recovering 1 week or longer after acute MI appears ineffective. Early routine administration of nifedipine in acute Ml, other than to patients in whom it may be specifically indicated (eg, those with Prinzmetal's variant angina or severe hypertension) may be hazardous and seems to be contraindicated.