Zosyn (Piperacillin-Tazobactam) Dosing for ESBL Urinary Tract Infections
For ESBL urinary tract infections, the recommended Zosyn (piperacillin-tazobactam) dosing is 3.375 g IV every 6 hours for 7-10 days. 1
Standard Dosing Regimen
- For adults with normal renal function, Zosyn should be administered at 3.375 g IV every 6 hours (totaling 13.5 g daily) by intravenous infusion over 30 minutes 1
- The usual duration of treatment for urinary tract infections is 7 to 10 days 1
- Piperacillin-tazobactam has shown efficacy against ESBL-producing organisms in urinary tract infections, particularly when the isolate shows in vitro susceptibility 2, 3
Dosing in Renal Impairment
- For patients with creatinine clearance 20-40 mL/min: 2.25 g IV every 6 hours 1
- For patients with creatinine clearance <20 mL/min: 2.25 g IV every 8 hours 1
- For hemodialysis patients: 2.25 g IV every 12 hours plus an additional 0.75 g after each dialysis session 1
- For CAPD patients: 2.25 g IV every 12 hours 1
Clinical Efficacy for ESBL UTIs
- Studies have shown clinical cure rates of approximately 74-89% when using piperacillin-tazobactam for non-bacteremic ESBL urinary tract infections 2, 3
- The best results are seen in urinary tract infections (100% cure rate in some studies), compared to intra-abdominal infections (70%) 3
- Clinical outcomes are generally better when the ESBL-producing organism has a minimum inhibitory concentration (MIC) ≤4 μg/mL for piperacillin-tazobactam 3
Treatment Duration
- Short-course therapy (≤7 days) has shown similar efficacy to longer courses (>7 days) for complicated UTIs caused by ESBL-producing organisms 4
- In one study, 30-day mortality was 5.7% in the short treatment group versus 5% in the long treatment group, with no significant differences 4
- The combined outcome of mortality or reinfection at 30 days was also similar between short and long treatment groups (8.6% vs. 10%) 4
Alternative Treatment Options
- Carbapenems (ertapenem, meropenem, imipenem) are considered first-line therapy for ESBL infections but should be used judiciously to prevent resistance 5, 2
- Aminoglycosides (amikacin, gentamicin) may be effective alternatives for ESBL UTIs, with some studies showing comparable efficacy to carbapenems 6, 7
- Fosfomycin has in vitro activity against ESBL-producing organisms and may be useful for uncomplicated cystitis when other oral agents are not available 5
Important Clinical Considerations
- Always confirm susceptibility of the ESBL-producing organism to piperacillin-tazobactam before using it as definitive therapy 2, 3
- Treatment failures are more common in high-inoculum infections or when source control is inadequate 3
- For bacteremic ESBL infections, carbapenems are still preferred over piperacillin-tazobactam due to higher failure rates with the latter in bloodstream infections 2
- Consider local resistance patterns when selecting empiric therapy for suspected ESBL infections 5