[A randomized, multicenter trial to compare the safety and efficacy of adenosine versus verapamil for termination of paroxysmal supraventricular tachycardia].

OBJECTIVE: To compare the safety and efficacy of intravenous adenosine with verapamil in terminating acute episodes of paroxysmal supraventricular tachycardia. METHODS: A randomized, multicenter trial to evaluate dose response in patients receiving adenosine and to compare the effects of adenosine with those of verapamil. A total of 122 patients with a tachycardia electrocardiographically consistent with paroxysmal supraventricular tachycardia were entered into the protocol. The adenosine group (n = 60) received sequential intravenous bolus doses of 3, 6, and 12 mg of adenosine to terminate PSVT and verapamil group (n = 62) were administrated 5mg or additional 5mg intravenously. Clinical variables and the time interval from the initiation of treatment to the termination of the supraventricular tachycardia, as well as the time from the initial effective dose of medication to the termination of supraventricular tachycardia were compared for adenosine and verapamil. RESULTS: There was no significant difference between the two groups with respect to clinical variables. Relative drug efficacies were 86.0% (52/60) for adenosine versus 87.1% (54/62) for verapamil, P = NS. The average time after injection to termination of tachycardia by adenosine was shorter than that of verapamil significantly [(34.2 +/- 19.5) seconds vs. (414.4 +/- 191.2) seconds, P < 0.0001]. Adenosine caused adverse effects in 18.3% of patients, but they were transient and usually mild. CONCLUSIONS: Adenosine in graded doses up to 12 mg rapidly and effectively terminates acute episodes of paroxysmal supraventricular tachycardia. The overall efficacy of adenosine is similar to that of verapamil, but its onset of action is more rapid. Adverse reactions to adenosine are common but are minor and brief.