Unasyn vs Zosyn
Archival post from 2012, preserved for continuity with prior inbound links. It does not reflect current clinical practice or technical guidance.
I've often asked by medical students what additional coverage is gained with using piperacillin-tazobactam (Zosyn) over ampicillin-sulbactam (Unasyn). The question comes up because so many people reflexively reach for "vanc-zosyn" for broad coverage. The answer is Pseudomonas.
The more difficult question is what additional coverage is gained with ampicillin-sulbactam over piperacillin-tazobactam. The answer is acinetobacter.
The additional coverage comes from the the sulbactam portion. This isn't to say that piperacillin-tazobactam should be a first line treatment, but it's interesting nonetheless.
