The U.S. Food and Drug Administration (FDA) and Pfizer Laboratories informed medical professionals last week that revisions have been made to the labeling for Pfizer's schizophrenia drug, Geodon. Also known as Ziprasidone, Geodon prolongs the heart's QT interval. According to the FDA and researchers working with Pfizer, Geodon should not be used with any drug associated with QT-prolongation.

The drug's contraindications section now lists every drug that prolongs the QT interval. These include dofetilide, sotalol, quinidine, other Class Ia and III anti-arrhythmics, mesoridazine, thioridazine, chlorpromazine, droperidol, pimozide, sparfloxacin, gatifloxacin, moxifloxacin, halofantrine, mefloquine, pentamidine, arsenic trioxide, levomethadyl acetate, dolasetron mesylate, probucol, or tacrolimus. The company also changed its warning label, adding that Geodon should be avoided in patients with congenital long QT syndrome and in patients with a history of cardiac arrhythmias.