A number of drugs, including Aventis S.A.'s Seldane terfenadine antihistamine and Johnson & Johnson's Propulsid cisapride gastric motility enhancer, have been taken off the market due to a common cardiovascular side effect, long QT syndrome, which predisposes patients to cardiac ventricular arrhythmia and potentially sudden death. By some estimates, the syndrome may be a side effect of half of all compounds under review for marketing approval in the U.S. and Europe.

Recent research, however, suggests an approach to avoiding the syndrome prior to clinical development. University of Utah (Salt Lake City, Utah) researchers and colleagues at Merck & Co. Inc. (MRK, Whitehouse Station, N.J.) last week published in the, Proceedings of the National Academy of Sciences, a structural basis for drug-induced long QT syndrome.