It must not be used in patients with severe liver disease or who are taking any of the following medicines: • terfenadine, astemizole (commonly used to treat allergy symptoms – these medicines may be available without prescription); • cisapride (used to relieve certain stomach problems); • midazolam, triazolam (used to relieve anxiety or difficulty sleeping); • pimozide (used to treat mental illnesses); • bepridil (used to treat angina); • ergot alkaloids such as ergotamine, dihydroergotamine, ergonovine and methylergonovine (used to treat migraine headache); • St John’ s wort (a herbal preparation used to treat depression); • voriconazole (used to treat fungal infections).