Adenosine as a therapeutic agent.

Adenosine, an endogenous nucleoside has been recently approved for use in the treatment of paroxysmal supraventricular tachycardia. Adenosine is nearly 100% effective in terminating tachycardia in which the atrioventricular node forms part of the reentrant circuit. Although most ventricular tachycardias are insensitive to adenosine, this substance is effective in ventricular tachycardia induced by catecholamines or exercise. An intravenous bolus dose of 6 mg is the initial dose. If no effect is noted a further bolus of 12 mg can be given. The most common side effects are dyspnea, chest pressure and facial flushing. This article reviews, in addition, some of the comparative trials with verapamil and adenosine triphosphate, some of the additional therapeutic indications, the possible mechanisms of action in cardiac tissue, and the type of purinergic receptors involved in the antiarrhythmic effects of adenosine.