Serious and occasionally fatal hypersensitivity (anaphylactic) reactions have been reported in patients on penicillin therapy. These reactions are more likely to occur in individuals with a history of penicillin hypersensitivity. If an allergic reactions occur, piperacillin and tazobactam sodium should be discontinued and appropriate therapy instituted. Serious anaphylactic reactions required immediate emergency treatment with epinephrine, oxygen, intravenous steroids and airway management, including intubation, should also be administered as indicated.