Safety of esmolol in patients with acute myocardial infarction treated with thrombolytic therapy who had relative contraindications to beta-blocker therapy.

OBJECTIVE

This study was conducted to evaluate the safety of esmolol in 114 patients treated with thrombolytic therapy for acute myocardial infarction who also had relative contraindications to beta-blockade, and the predictive value of patient tolerance to esmolol and subsequent patient tolerance of oral beta-blocker therapy.

PATIENTS

One hundred and fourteen patients with myocardial infarction documented by enzyme concentrations and electrocardiographic changes who also had relative contraindications to beta-blockade.

METHODS

Esmolol was initiated during acute myocardial infarction for myocardial ischemia (n = 88), hypertension (n = 13), or supraventricular tachycardia (n = 13). Relative contraindications to beta-blocker therapy included either active signs/symptoms of left ventricular dysfunction or a history of congestive heart failure (n = 40), a history of chronic obstructive pulmonary disease or asthma (n = 31), bradycardia (HR < 60 beats/min; n = 18), peripheral vascular disease (n = 15), or hypotension (systolic BP < 100 mm Hg; n = 14).

RESULTS

During initial esmolol dose titration, 69 patients tolerated 300 micrograms/kg/min, 12 patients tolerated 200 micrograms/kg/min, 17 patients tolerated 100 micrograms/kg/min, and 16 patients tolerated 50 micrograms/kg/min. Twenty-eight patients (25 percent) developed dose-limiting adverse effects during esmolol maintenance infusions. Sixteen patients required esmolol dose reduction and 12 required esmolol discontinuation. Adverse effects reversed within 30-45 minutes following dose reduction or discontinuation. The 86 patients who tolerated esmolol infusions without dose reduction or drug discontinuation were subsequently treated with oral beta-blockers. Eleven of these patients (13 percent) developed adverse effects requiring oral beta-blocker discontinuation. Nine of these patients had tolerated only 50 micrograms/kg/min of esmolol, and the other 2 patients had tolerated only 100 micrograms/kg/min.

CONCLUSIONS

Esmolol can be used safely in most patients treated with thrombolytic therapy for acute myocardial infarction who have relative contraindications to beta-blockers. Tolerance to higher maintenance doses of esmolol is a good predictor of subsequent outcome with oral beta-blocker therapy.