Mibefradil ? a drug which may enhance the propensity for the development of abnormal QT prolongation

Mibefradil is a moral calcium antagonist that is selective for the T-type voltage-operated calcium channel. It has been shown to be effective in hypertension and in stable angina. Shortly following its introduction, mibefradil was withdrawn from the market because of potentially harmful interactions with other drugs. Of special interest is the possible interaction of mibefradil with drugs which prolong the QT interval (e.g. amiodarone, quinidine, sotalol, erythromycin, desimipramine and thioridazine). This short review summarizes the effects of mibefradil on cardiac repolarization and possible implications for drug interactions with QT prolonging agents.