QT-prolonging drugs: Should they ever be used?

If the current stringent conditions of bodies that register and control medicines had been in force for decades, many commonly used drugs (from antibiotics and antihistamines to antipsychotics and antiarrhythmics) would never have reached the consumer market. Nowadays, pre-release findings of QT prolongation are likely to scupper early-phase trials and result in the abandonment of experimental drugs. Post-marketing surveillance has identified a number of commonly used drugs either as causing QT prolongation or associated with increased sudden unexpected deaths.1 Thioridazine (see p. 46 of this issue) is such a drug