Zosyn (Piperacillin/Tazobactam) Coverage and Dosage for Bacterial Infections
Piperacillin/tazobactam (Zosyn) is a broad-spectrum antimicrobial agent effective against most Gram-positive and Gram-negative aerobic bacteria and anaerobic bacteria, including many beta-lactamase producing pathogens, and is indicated for intra-abdominal infections, nosocomial pneumonia, skin and skin structure infections, female pelvic infections, and community-acquired pneumonia. 1
Spectrum of Coverage
Piperacillin/tazobactam provides coverage against a wide range of pathogens including:
- Gram-positive organisms: Streptococci and methicillin-susceptible Staphylococcus aureus (MSSA) 2, 3
- Gram-negative organisms: Most Enterobacterales including Escherichia coli, Klebsiella species, and Pseudomonas aeruginosa 2, 4
- Anaerobic bacteria: Bacteroides fragilis group and Clostridium species 2, 5
The addition of tazobactam (beta-lactamase inhibitor) significantly enhances piperacillin's activity against:
Standard Dosing for Adults
For most infections in adults with normal renal function:
- 3.375 g (3 g piperacillin/0.375 g tazobactam) every 6 hours, totaling 13.5 g daily 1
For nosocomial pneumonia in adults:
Administration: Intravenous infusion over 30 minutes 1
Clinical Indications
1. Intra-abdominal Infections
- Recommended for complicated intra-abdominal infections, particularly for nosocomial infections or those with risk of Pseudomonas 6
- Effective for polymicrobial infections involving aerobic and anaerobic pathogens 6
2. Skin and Soft Tissue Infections (SSTIs)
- Recommended for severe non-purulent cellulitis, especially when combined with vancomycin for MRSA coverage 6
- Particularly useful in necrotizing infections of skin, fascia, and muscle 6
3. Nosocomial Pneumonia
- Recommended as part of empiric therapy for hospital-acquired pneumonia in patients at high risk of mortality 6
- Often combined with vancomycin or linezolid when MRSA coverage is needed 6
4. Multidrug-Resistant Infections
- Effective option for infections due to susceptible strains of carbapenem-resistant Pseudomonas aeruginosa at doses of 3-4 g every 6 hours 6
- May be used in optimized dosing regimens for certain resistant infections 6
Dosage Adjustments
Renal impairment: Dosage reduction required for patients with creatinine clearance ≤40 mL/min 1
Pediatric patients (2 months to 9 months):
- For appendicitis/peritonitis: 90 mg/kg every 8 hours
- For nosocomial pneumonia: 90 mg/kg every 6 hours 1
Pediatric patients (older than 9 months):
- For appendicitis/peritonitis: 112.5 mg/kg every 8 hours
- For nosocomial pneumonia: 112.5 mg/kg every 6 hours 1
Treatment Duration
- For skin and soft tissue infections: 5-10 days, extending if infection has not improved 6
- For intra-abdominal infections: 5-7 days after adequate source control 6
- For nosocomial pneumonia: 7-14 days 6
Clinical Considerations and Cautions
Piperacillin/tazobactam should be administered separately from aminoglycosides to avoid inactivation 1
Common adverse effects include gastrointestinal symptoms (particularly diarrhea) and skin reactions 4
More serious adverse events may include hypersensitivity reactions, severe cutaneous adverse reactions, hemophagocytic lymphohistiocytosis, and rhabdomyolysis 1
For severe infections with risk of resistant pathogens, combination therapy may be warranted:
Antimicrobial Stewardship Considerations
- Piperacillin/tazobactam should be reserved for moderate to severe infections where broad-spectrum coverage is necessary 6
- For less severe community-acquired infections, narrower spectrum agents may be more appropriate 6
- Culture results should guide de-escalation of therapy when possible to reduce the risk of resistance development 1