Cisapride was withdrawn from market due to?: (A) QT Prolongation, (B) Increased PR interval, (C) Teratogenicity, (D) Myocardial damage
Answer is A. ANSWER: (A) QT ProlongationREF: Lippincott's 4th ed ch: 17See previous question for list of drugs causing QT prolongationInhibition of potassium channels widens the action potential, leading to a prolonged QT interval on the electrocardiogram. Such an effect is associated with increased risk of developing life-threatening ventricular tachyarrhythmias (torsades de pointes). The most common cause of QT prolongation is drug-induced, although it may also be genetic.