Lay Summary: Prolongation of the QT interval and cardiac arrhythmias associated with cisapride

Experience has shown that it is not possible to identify all the important side effects due to medicines before they are put on the market. Heart rhythm disorders are a rare side effect of cisapride, a medicine used to treat indigestion and heartburn. In the UK cisapride was marketed from 1989 until 2000, when it was withdrawn because of concern about reported serious and sometimes fatal heart rhythm disorders. Even by the time it was withdrawn from the market, the degree of risk associated with use of cisapride was uncertain and several studies had failed to confirm the risk, probably because the numbers of users of cisapride included were too few.

The occurrence of heart rhythm disorders may be predicted from tracings of the heartbeat showing a change in the electrical impulse, known as QT interval prolongation. Since QT interval prolongation may be produced by various medicines, but the associated risks remain uncertain, we recommend that a registry of cases be established. This would enable similar problems to be identified earlier and help to minimise the risks to patients.