Potentiated hypotensive & sedative effects of tizanidine. Elevated serum conc & prolonged elimination t½
of theophylline. May slow down the liver processing of clozapine. Synergism & alteration of physiological control loop of vit K w/ warfarin. Do not take orally when in concomitant use w/ Al hydroxide. Reduced effectiveness w/ products containing Mg, Al, Ca, Fe &/or other minerals. May cause dangerous abnormal heart rhythm w/ oral ondansetron.