Ask Patients with Chest Pain About Viagra Use

The interaction of sildenafil (Viagra) and nitrates has resulted in protracted and profound hypotension leading to death in some cases. An expert panel of the American College of Cardiology and the American Heart Association reviewed published and unpublished data from Pfizer to advise practicing physicians.

More than 3,700 patients received sildenafil in controlled studies. Some had cardiovascular disease but none were taking long-acting nitrates. More than 3.6 million prescriptions have been filled. Of 69 reported deaths, 21 were due to unknown causes, 2 to stroke, and 46 to cardiovascular causes. Twelve deaths were possibly related to an interaction between Viagra and nitrates. Although data are scarce, the panel states that nitrates are contraindicated in patients who have taken sildenafil in the previous 24 hours. The interaction period is longer for patients with renal or hepatic dysfunction or who are taking any drugs that inhibit or use the cytochrome P450 3A4 pathway (e.g., erythromycin and clotrimazole). In patients with acute coronary syndromes, other anti-ischemic therapies should be used. Twenty-four hours after sildenafil use, low-dose IV nitroglycerin can be tried under full monitoring and with the ability to provide fluid resuscitation and alpha agents.

Comment: There is evidence that physicians seek information about sildenafil use infrequently before initiating nitroglycerin therapy. Questioning patients is necessary to avoid a potentially preventable bad outcome.

— JM Christenson

Published in Journal Watch Emergency Medicine July 1, 1999

Source

Chietlan MD et al. Use of Sildenafil (Viagra) in patients with cardiovascular disease. J Am Coll Cardiol 1999 Jan 33 273-282