Intraabdominal infection penicillin

CS, a 55-year-old woman, is admitted to the hospital with an intraabdominal infection. During the patient interview, CS states that she is allergic to aspirin, codeine, sulfa drugs, penicillin, levofloxacin, and vancomycin. The reactions are described as follows ... 

When used for intraabdominal infection, aminoglycosides should be combined with agents that are effective against the majority of B. fragilis. Clindamycin or metronidazole is the agent of first choice, but others, such as antianaerobic cephalosporins (e.g., cefoxitin, cefotetan, or ceftizoxime), piperacillin, mezlocillin, and combinations of extended-spectrum penicillins... 

The indications for penicillin-B-lactamase inhibitor combinations are empirical therapy for infections caused by a wide range of potential pathogens in both immunocompromised and immunocompetent patients and treatment of mixed aerobic and anaerobic infections, such as intraabdominal infections. Doses are the same as those used for the single agents except that the recommended dosage of piperacillin in the piperacillin-tazobactam combination is 3 g every 6 hours. This is less than the recommended 3-4 g every 4-6 hours for piperacillin alone, raising concerns about the use of the combination for treatment of suspected pseudomonal infection. Adjustments for renal insufficiency are made based on the penicillin component. 

Imipenem-cilastatin is one of the drugs of first choice for the empirical therapy of many polymicrobial pulmonary, intraabdominal, and soft tissue infections. The notable adverse effect of imipenem-cilastatin is seizures affecting 1% of patients. Risk factors for seizures are old age, head trauma, previous seizure disorder, cerebrovascular accident, and renal failure. Among patients with a history of penicillin allergy, 10% are cross-sensitive to imipenem-cilastatin. 

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