Clarithromycin can increase the levels of
pimozide, which is believed to increase its serious cardiotoxicity. The manufacturers predict that other
macrolides will interact similarly, but note that not all
macrolides would be expected to interact, see
macrolides. Erythromycin slightly raises the levels of sertindole, and concurrent use increases the
incidence of adverse effects (diarrhoea, abdominal pain, dizziness) but no ECG changes appear to occur.
The concurrent use of
macrolides is contraindicated with
pimozide and sertindole because of the risks of QT interval prolongation. Consider also drugs that prolong the QT interval.