What is the recommended dosing regimen for ertapenem (a carbapenem antibiotic) for the treatment of urinary tract infections (UTIs)?

Ertapenem Dosing for Urinary Tract Infections

For urinary tract infections (UTIs), ertapenem should be administered at a dose of 1 gram once daily intravenously for adults, and 15 mg/kg every 12 hours (for children 3 months to 12 years) or 1 gram once daily (for adolescents 13-17 years). 1

Dosing Regimens by Patient Population

Adult Patients

• Standard dose: 1 gram IV once daily 1, 2, 3
• Duration:
  • Uncomplicated UTIs: 5-7 days 4
  • Complicated UTIs: 7-14 days 4, 2
  • Average treatment duration in clinical trials: 4 days parenteral followed by oral therapy for a total of approximately 13 days 2, 3

Pediatric Patients

• Children 3 months to 12 years: 15 mg/kg IV every 12 hours 1
• Adolescents 13-17 years: 1 gram IV once daily 1
• Clinical trials showed high efficacy rates (87-90%) for pediatric UTIs with this dosing regimen 1

Administration Options

Intravenous Administration

• Reconstitute with appropriate diluent
• May be administered as a 30-minute infusion 1
• Can be stored at room temperature for up to 6 hours after reconstitution or refrigerated for 24 hours (and used within 4 hours after removal from refrigeration) 1

Transition to Oral Therapy

• After ≥3 days of parenteral therapy, patients with clinical improvement can be switched to appropriate oral antibiotics 2, 5, 3
• In clinical trials, approximately 95-96% of patients were successfully transitioned to oral therapy (commonly ciprofloxacin) 2, 3

Efficacy and Safety

• Ertapenem has demonstrated high efficacy rates (85.6-91.8%) for complicated UTIs, comparable to ceftriaxone 2, 5, 3, 6
• Particularly effective against ESBL-producing organisms in complicated UTIs 7
• Short-course therapy (median 6 days) has shown clinical cure rates of 81-96% when used alone or with adjunctive fosfomycin 7

Special Considerations

• Obtain urine culture before starting therapy, especially in complicated cases 4
• Consider local resistance patterns when selecting empiric therapy 4
• Adjust therapy based on culture and susceptibility results 4
• For multidrug-resistant organisms, infectious disease consultation is highly recommended 4

Potential Pitfalls

1. Catheter-associated UTIs: Replace indwelling catheters that have been in place for ≥2 weeks before starting antimicrobial therapy 4

2. Follow-up: Obtain follow-up urine culture 1-2 weeks after completing therapy if symptoms persist 4

3. Treatment failure: If bacteriuria recurs after treatment, select alternative agents rather than repeating the same antibiotic 4

4. Drug interactions: Patients taking valproic acid should be counseled that ertapenem may decrease valproic acid concentrations, potentially requiring alternative or supplemental anticonvulsant medication 1

Ertapenem has proven to be highly effective for both complicated UTIs and acute pyelonephritis with clinical success rates comparable to other parenteral antibiotics while offering the convenience of once-daily dosing 2, 5, 3.