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From the FDA Drug Label
INDICATIONS AND USAGE Piperacillin and Tazobactam for Injection is a combination of piperacillin, a penicillin-class antibacterial and tazobactam, a beta-lactamase inhibitor, indicated for the treatment of: Intra-abdominal infections in adult and pediatric patients 2 months of age and older (1.1) Nosocomial pneumonia in adult and pediatric patients 2 months of age and older (1. 2) Skin and skin structure infections in adults (1.3) Female pelvic infections in adults (1.4) Community-acquired pneumonia in adults (1. 5)
The FDA drug label does not answer the question.
From the Research
Coverage Difference
The coverage difference between Unasyn (Ampicillin/Sulbactam) and Zosyn (Piperacillin/Tazobactam) can be summarized as follows:
- Unasyn has been shown to be effective against a range of bacteria, including Staphylococcus epidermidis, Staphylococcus aureus, Serratia, Streptococcus, and E. coli 1, 2
- Zosyn has a broader spectrum of antibacterial activity, encompassing most Gram-positive and Gram-negative aerobic bacteria and anaerobic bacteria, including many pathogens producing beta-lactamases 3
- A study comparing the in vitro activity of three combinations of beta-lactams with beta-lactamase inhibitors found that piperacillin/tazobactam (Zosyn) was more active against all Gram-negative species than ampicillin/sulbactam (Unasyn), with the exception of Acinetobacter baumannii 4
- Another study found that tazobactam-piperacillin (Zosyn) had a broad antibacterial spectrum against Gram-negative and Gram-positive bacteria, and its antibacterial activity was at least 4- to 64-fold stronger than that of piperacillin, clavulanic acid-ticarcillin, and sulbactam-ampicillin against beta-lactamase-producing bacteria 5
Key Findings
- Zosyn has a broader spectrum of activity against Gram-negative bacteria, including Enterobacteriaceae and Pseudomonas aeruginosa 3, 4
- Unasyn is effective against Gram-positive bacteria, including Staphylococcus aureus and Streptococcus 1, 2
- Zosyn is more active against beta-lactamase-producing bacteria than Unasyn 5
Bacterial Coverage
- Unasyn:
- Staphylococcus epidermidis
- Staphylococcus aureus
- Serratia
- Streptococcus
- E. coli
- Zosyn:
- Most Gram-positive and Gram-negative aerobic bacteria
- Anaerobic bacteria
- Many pathogens producing beta-lactamases, including:
- Enterobacteriaceae
- Pseudomonas aeruginosa
- Acinetobacter baumannii (less active than Unasyn)