Enhanced sedation or risk of resp or CV depression w/ CNS depressants (eg, anticonvulsants, anxiolytics/hypnotics, sedative antihistamines, alcohol, neuroleptics, antidepressants, analgesics, anaesth). Altered plasma conc of phenytoin. Reduced plasma levels w/ phenytoin & carbamazepine. Increased sedation or resp depression w/ barbiturates. Increased plasma levels w/ Na valproate, fluvoxamine. Reduced attention & psychomotor performance w/ SSRIs or TCAs. Increased plasma levels of zotepine. Occurrence of severe hypotension, collapse, loss of consciousness, resp depression, & potentially fatal resp arrest, salivary hypersecretion w/ clozapine. Hypotension, bradycardia & resp depression w/ IM olanzapine. Enhanced effects of Na oxybate (γ hydroxybutyrate, GHB). Inhibited metabolism w/ isoniazid & erythromycin; gastric acid suppressants (eg, cimetidine, omeprazole, esomeprazole); disulfiram. Increased clearance w/ hepatic enzyme inducer (eg, rifampicin). Reduced clearance w/ antivirals (eg, amprenavir, ritonavir). Increased effects w/ azole antifungals (eg, voriconazole, fluconazole, itraconazole). Enhanced sedative effects w/ alcohol; α-blockers or moxonidine; skeletal muscle relaxants (eg, baclofen or tizanidine). Enhanced hypotensive effects w/ antihypertensive agents. Antagonised effects of levodopa. Reduced effects w/ theophylline.