Increased risk of CNS toxicity w/ NMDA eg, amantadine, ketamine & dextromethorphan. Enhanced effect of dopaminergic agonists eg, bromocriptine & anticholinergics. Reduced effect of barbiturates & neuroleptics. Modified antispasmodic effect w/ dantrolene or baclofen. Enhanced oral anticoagulant effect w/ warfarin. Increased plasma levels of cimetidine, ranitidine, procainamide, quinidine, quinine & nicotine. Reduced plasma levels of diuretics eg, hydrochlorothiazide, triamterene. Reduced effect of primidone. Enhanced effect of selegiline.