Increased C
max of levodopa. Reduced renal clearance w/ drugs eliminated via the renal cationic transport system (eg, amantadine, cimetidine, ranitidine, diltiazem, triamterene, verapamil, quinidine, quinine). Reduced therapeutic effects w/ dopamine antagonists eg, neuroleptics (eg, phenothiazines, butyrophenones, thioxanthines); metoclopramide. Possible additive effects w/ sedating medications or alcohol.