Enhanced effects of l-dopa, dopaminergic agonists, anticholinergics. Reduced effects of barbiturates, neuroleptics. Modified effects of antispasmodic agents, dantrolene or baclofen. Risk of pharmacotoxic psychosis w/ amantadine, ketamine, dextromethorphan. Risk of increased plasma levels w/ cimetidine, ranitidine, procainamide, quinidine, quinine, nicotine. Reduced serum level possibility of hydrochlorothiazide. Increased INR w/ warfarin.