Duration of Invanz (Ertapenem) for Female UTI
For complicated UTIs in women, including acute pyelonephritis, administer Invanz (ertapenem) for 7-14 days total, with a typical approach being 3-5 days of IV therapy followed by oral step-down to complete 10-14 days total treatment.
Treatment Duration Based on UTI Type
Uncomplicated Cystitis
- Invanz is NOT indicated for uncomplicated cystitis 1
- First-line agents include nitrofurantoin (5 days), trimethoprim-sulfamethoxazole (3 days), or fosfomycin (single dose) 2, 1
- Reserve carbapenems like ertapenem for complicated infections or resistant organisms 1
Complicated UTI/Acute Pyelonephritis
- Standard duration: 7-14 days total therapy 1
- Typical IV duration: 3-5 days of parenteral ertapenem, then switch to oral therapy based on clinical stability 3
- In clinical trials, median parenteral ertapenem duration was 4 days (range 2-14 days), with median total therapy of 13 days 3
- Extended 14-day duration recommended when prostatitis cannot be excluded or for severe complicated infections 1
Practical Treatment Algorithm
Initial Assessment
- Obtain urine culture and susceptibility testing before starting therapy 1
- Classify as uncomplicated cystitis, pyelonephritis, or complicated UTI based on presence of fever, flank pain, structural abnormalities, obstruction, or instrumentation 1
IV-to-Oral Transition Criteria
- Switch to oral therapy once hemodynamically stable and afebrile 1
- Typically occurs after 3-5 days of IV ertapenem 3
- Oral step-down options include ciprofloxacin 500-750 mg twice daily, levofloxacin 750 mg daily, or trimethoprim-sulfamethoxazole 160/800 mg twice daily (based on susceptibilities) 1
Total Duration Decision Points
- 7 days total: Appropriate for uncomplicated pyelonephritis when highly bioavailable oral agents (fluoroquinolones) are used for step-down 4
- 10 days total: Standard for most complicated UTIs without bacteremia 4
- 14 days total: Required when beta-lactams are used throughout, bacteremia is present, or when prostatitis cannot be excluded in males 1, 4
Key Clinical Considerations
Evidence Quality
- The 7-14 day recommendation comes from European Urology guidelines and is supported by randomized trials showing ertapenem equivalence to ceftriaxone with similar treatment durations 1, 3
- Recent 2023 data suggests 7 days may suffice for complicated UTI with bacteremia when highly bioavailable oral agents are used, but 10 days is safer for beta-lactam-based regimens 4
Common Pitfalls to Avoid
- Do not use ertapenem for simple cystitis - this represents inappropriate carbapenem use and promotes resistance 1
- Do not continue IV therapy beyond clinical stability - 96% of patients in trials successfully transitioned to oral therapy, reducing costs and adverse events 3
- Do not treat for <7 days total unless using highly bioavailable oral fluoroquinolones, as shorter courses increase recurrence risk 4