WARNINGSSERIOUS AND OCCASIONALLY FATAL HYPERSENSITIVITY (ANAPHYLACTIC SHOCK WITH COLLAPSE) REACTIONS HAVE OCCURRED IN PATIENTS RECEIVING PENICILLIN. THE INCIDENCE OF ANAPHYLACTIC SHOCK IN ALL PENICILLIN-TREATED PATIENTS IS BETWEEN 0.015 AND 0.04 PERCENT. ANAPHYLACTIC SHOCK RESULTING IN DEATH HAS OCCURRED IN APPROXIMATELY 0.002 PERCENT OF THE PATIENTS TREATED. ALTHOUGH ANAPHYLAXIS IS MORE FREQUENT FOLLOWING PARENTERAL ADMINISTRATION, IT HAS OCCURRED IN PATIENTS RECEIVING ORAL PENICILLINS.

WHEN PENICILLIN THERAPY IS INDICATED, IT SHOULD BE INITIATED ONLY AFTER A COMPREHENSIVE PATIENT DRUG AND ALLERGY HISTORY HAS BEEN OBTAINED. IF AN ALLERGIC REACTION OCCURS, THE DRUG SHOULD BE DISCONTINUED AND THE PATIENT SHOULD RECEIVE SUPPORTIVE TREATMENT, E.G., ARTIFICIAL MAINTENANCE OF VENTILATION, PRESSOR AMINES, ANTIHISTAMINES, AND CORTICOSTEROIDS. INDIVIDUALS WITH A HISTORY OF PENICILLIN HYPERSENSITIVITY MAY ALSO EXPERIENCE ALLERGIC REACTIONS WHEN TREATED WITH A CEPHALOSPORIN.

Clostridium difficile associated diarrhea (CDAD) has been reported with use of nearly all antibacterial agents, including oxacillin for injection, and may range in severity from mild diarrhea to fatal colitis. Treatment with antibacterial agents alters the normal flora of the colon leading to overgrowth of C. difficile.

C. difficile produces toxins A and B which contribute to the development of CDAD. Hypertoxin producing strains of C. difficile cause increased morbidity and mortality, as these infections can be refractory to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea following antibiotic use. Careful medical history is necessary since CDAD has been reported to occur over two months after the administration of antibacterial agents.

If CDAD is suspected or confirmed, ongoing antibiotic use not directed against C. difficile may need to be discontinued. Appropriate fluid and electrolyte management, protein supplementation, antibiotic treatment of C. difficile , and surgical eva luation should be instituted as clinically indicated.
PRECAUTIONSGeneralOxacillin should generally not be administered to patients with a history of sensitivity to any penicillin.

Penicillin should be used with caution in individuals with histories of significant allergies and/or asthma. Whenever allergic reactions occur, penicillin should be withdrawn unless, in the opinion of the physician, the condition being treated is life-threatening and amenable only to penicillin therapy.

The oral route of administration should not be relied upon in patients with severe illness, or with nausea, vomiting, gastric dilation, cardiospasm, or intestinal hypermotility. Occasionally patients will not absorb therapeutic amounts of orally administered penicillin.

The use of antibiotics may result in overgrowth of nonsusceptible organisms. If new infections due to bacteria or fungi occur, the drug should be discontinued and appropriate measures taken.

Prescribing Oxacillin for Injection in the absence of a proven or strongly suspected bacterial infection or a prophylactic indication is unlikely to provide benefit to the patient and increases the risk of the development of drug-resistant bacteria.

Information for Patients
Patients should be counseled that antibacterial drugs including Ox