These include some antibiotics (e. g. erythromycin and clarithromycin), antifungal medicines (e. g. ketoconazole and itraconazole), antipsychotic medicines (e. g. thioridazine), some antidepressants (e. g. imipramine), antiviral medicines (e. g. nelfinavir and ritonavir), some medicines used to treat heart problems (e. g. flecainide, verapamil and digoxin) and other antimuscarinic medicines (e. g. tolterodine, oxybutynin and flavoxate).