Cefixime should be given with caution to patients who have shown hypersensitivity to other medicines. Cephalosporins should be given with caution to penicillin-sensitive patients as there is some evidence of partial cross-allergenicity between the penicillins and the cephalosporins. Patients have had severe reactions (including anaphylaxis) to both classes of drugs. If an allergic effect occurs with Cefixime the drug should be discontinued and the patient treated with appropriate agents if necessary. Cefixime should be administered with caution in patients with markedly impaired renal function. Prolonged use of Cefixime may result in the overgrowth of non-susceptible organisms. Cefixime has been shown to alter the normal flora of the colon and may permit overgrowth of Clostridia. Studies indicate a toxin(s) produced by Clostridium difficile is the primary cause of antibiotic associated pseudomembranous colitis. The product should be discontinued if diarrhea occurs.