Co-administration may result in competitive inhibition of the metabolism of these active substances thus increasing their plasma level and leading to serious and / or life-threatening adverse reactions such as cardiac arrhythmia (e. g. amiodarone, astemizole, bepridil, cisapride, pimozide, quinidine, terfenadine) or peripheral vasospasm or ischaemia (e. g. ergotamine, dihydroergotamine) (see section 4.3).