Co-administration with medicinal products with narrow therapeutic windows and which are substrates of CYP3A4 [e.g., terfenadine, astemizole, cisapride, amiodarone, quinidine, pimozide, triazolam, orally administered midazolam (for caution on parenterally administered midazolam, see section 4.5), ergot derivatives; see section 4.5].