Esmolol is a new cardioselective beta blocker with unique pharmacokinetic properties resulting in a half-life of only 9 minutes. The present multicenter, randomized, placebo-controlled study examined the hemodynamic and antiischemic effects of this compound given as an adjunctive to conventional medical
therapy in 113 patients with
unstable angina. Fifty-nine patients received
esmolol and 54 received matching placebo infusions.
Esmolol was titrated in a step-wise manner at dosages of 2 to 24 mg/min until a 25% reduction in the double product was achieved; thereafter,
esmolol was continuously infused for up to 72 hours.
Esmolol caused a significant and persistent decline in heart rate and blood pressure throughout the entire study period. Clinical events, such as development of acute
myocardial infarction or the need for urgent revascularization, occurred in 3
esmolol compared with 9 placebo patients (p = 0.06). There was also a trend toward reduction of silent
ischemia as judged by Holter monitoring (mean [+/- standard deviation] duration/patient/24 hours, 21 +/- 81 minutes in the
esmolol and 35 +/- 128 minutes in the placebo groups).
Esmolol-related adverse effects were mostly cardiovascular in origin and could be managed promptly by downward dose titration or cessation of
drug infusion. Thus,
esmolol appears to be a safe and effective
drug for patients with
unstable angina because it permits a large degree of flexibility in adapting the desired level of beta blockade to the patient's changing clinical presentation.