Infectious Disease Compendium

Piperacillin/Tazobactam (Zosyn®)


CrCl Formula

CrCl > 80: 2.5 - 4.5 iv q 6 - 8 h. Probably best to dose q 8 with a 4 hour infusion.

CrCl 80-50: 2.5 - 4.5 iv q 6 - 8 h.

CrCl 50-10: ?

CrCl < 10: ?


Peritoneal dialysis:

Obesity dosing

Important side effects

Important drug interactions

Methotrexate, probenecid, vecuronium.

When added to vancomycin it is associated with acute kidney injury (PubMed) (PubMed).

A meta-analysis suggests an odds ratio of 3 for AKI (PubMed) when combined with vancomycin.

Rants and Screeds

Use of this antibiotic in sepsis empirically is associated with increased mortality rates compared to other agents, especially if the MIC is in the high end of 'sensitive', greater than 2 ug/ml.

Funny how we had a piperacillin shortage (inexpensive) but plenty of pip/tazo (expensive). Wonder why?


Beta-lactamse inhibitor combinations are problematic with some gram negative rods, depending on the strain and the type of beta-lactamase. Clavulanate can be antagonistic for ticarcillin (PubMed) and other beta lactam antibiotics (PubMed). This is less of a problem with tazobactam, maybe occurring 1% of the time (PubMed).

Treatment of choice

In my opinion? Nothing. I do not believe I have ever used the drug.

Use for

Like all beta lactamase inhibitor combination, I can't find a use for them. It is approved for Appendicitis, Cellulitis, cutaneous abscesses, Diabetic foot infection, Diverticulosis/itis, Endometritis, Escherichia coli infections, gynecologic infections, Intra abdominal infections, Neutropenic fever, PID, Peritonitis, Pneumonia.

Don't use for