Janssen Pharmaceutica revised its labeling of cisapride (Propulsid) in late January to include a rare boxed warning regarding potentially fatal drug interactions.

The drug, used to accelerate gastric emptying in patients with gastric/duodenal ulcers or gastroesophageal reflux disease (GERD), may precipitate possibly fatal cardiac dysrhythmias when used concomitantly with certain antidepressant and antipsychotic medications, as well as other medications.

Specifically, the warning cites the use of cisapride with the following pyschotropic medications as contraindicated: the antidepressants amitriptyline (Elavil), maprotiline (Ludiomil), and nefazodone (Serzone) and the antipsychotics prochlorperazine (Compazine) and sertindole (Serlect). When these medications are used concomitantly with cisapride, serious cardiac dysrythmias, including ventricular tachycardia, ventricular fibrillation, torsades de pointes, and QT prolongation have been reported. These dysrhythmias may present as palpitations, syncope, and/or sudden cardiac death. Most cases have occurred in patients with known risk factors for dysrhythmias.

Physicians using antidepressant and antipsychotic drug therapy should be aware of the potential interaction and assess the risk-benefit profile of the specific medications indicated to determine whether the drug therapy should be adjusted, according to the manufacturer.