History of hypersensitivity to penicillin or other cephalosporins. Pseudomembranous colitis. Prolonged use. Discontinue use if superinfection occurs. Monitor prothrombin time in patients w/ renal or hepatic impairment or poor nutritional state, receiving protracted course of antimicrobial therapy & previously stabilized on anticoagulant therapy. Patients w/ end-stage renal disease, patients w/ severe hepatic impairment. Concomitant use w/ antacids or drugs taken to reduce stomach acid. Pregnancy & lactation. Ped patients <12 yr. Elderly.