Alert to physicians: possible interaction of aggrenox and adenosine.

A new medication, Aggrenox, a formulation of aspirin and extended-release dipyridamole, is now being actively marketed to physicians for the treatment of patients with transient ischemic attacks and ischemic stroke. I believe that physicians involved in pharmacological stress testing should recognize that patients taking this medicine may also be referred for an adenosine pharmacologic stress perfusion test. It would be anticipated that the extended-release formulation of dipyridamole would antagonize the breakdown of adenosine and, thereby, exaggerate adenosine’s effects, including the induction of hypotension and atrialventricular block. Patients receiving Aggrenox should not receive adenosine but should receive dipyridamole instead. I believe the readers of the Journal of the American College of Cardiology (JACC) should be warned of the possible interaction of Aggrenox and adenosine.