What is the recommended dosage and treatment duration for Ertapenem (Merrem) IV for severe bacterial infections?

Ertapenem IV Dosing and Administration

Standard Dosing Regimen

For adults and pediatric patients 13 years and older, administer ertapenem 1 gram IV once daily, infused over 30 minutes, with treatment duration ranging from 3-14 days depending on the infection type and clinical response. 1

Adult Dosing by Indication

• Complicated intra-abdominal infections: 1 g IV once daily for 5-14 days 2, 1
• Complicated skin and skin structure infections (including diabetic foot infections): 1 g IV once daily for 7-14 days 1
• Community-acquired pneumonia: 1 g IV once daily for 10-14 days (duration includes possible switch to oral therapy after ≥3 days of parenteral therapy once clinical improvement demonstrated) 1
• Complicated urinary tract infections/pyelonephritis: 1 g IV once daily for 10-14 days 1
• Acute pelvic infections: 1 g IV once daily for 3-10 days 1
• Surgical prophylaxis (elective colorectal surgery): Single 1 g IV dose given 1 hour prior to surgical incision 1

Pediatric Dosing (3 months to 12 years)

• Standard dose: 15 mg/kg IV twice daily (maximum 1 g/day) 2, 1
• Treatment durations follow the same infection-specific guidelines as adults 1

Special Populations

Renal Impairment

• Creatinine clearance >30 mL/min/1.73 m²: No dose adjustment necessary 1
• Creatinine clearance ≤30 mL/min/1.73 m²: Reduce to 500 mg IV once daily 1
• End-stage renal disease (CrCl ≤10 mL/min/1.73 m²): 500 mg IV once daily 1

Hemodialysis Patients

• Administer 500 mg daily as the standard dose 1
• If ertapenem given within 6 hours before hemodialysis: Give supplementary dose of 150 mg after the dialysis session 1
• If ertapenem given ≥6 hours before hemodialysis: No supplementary dose needed 1

Hepatic Impairment

• No specific dose adjustment recommendations available; use with caution 1

Duration of Therapy Based on Clinical Context

For Immunocompetent, Non-Critically Ill Patients

• With adequate source control: 4 days of antibiotic therapy 2, 3
• This shortened duration applies when surgical or drainage procedures have successfully controlled the infection source 2

For Immunocompromised or Critically Ill Patients

• With adequate source control: Up to 7 days based on clinical conditions and inflammatory markers 2, 3
• Patients with ongoing infection signs beyond 7 days: Warrant further diagnostic investigation 2, 3

For Patients with Inadequate/Delayed Source Control

• Ertapenem 1 g once daily is specifically recommended for patients at high risk of ESBL-producing Enterobacterales 2, 3
• Treatment duration should be individualized based on achievement of source control and clinical response 2

Critical Administration Details

Preparation and Infusion

• DO NOT mix or co-infuse with other medications 1
• DO NOT use diluents containing dextrose 1
• Reconstitute 1 g vial with 10 mL of Water for Injection, 0.9% Sodium Chloride, or Bacteriostatic Water 1
• Dilute reconstituted solution in 50 mL of 0.9% Sodium Chloride 1
• Infuse over 30 minutes 1
• Complete infusion within 6 hours of reconstitution 1

Intramuscular Alternative

• IM administration may be used for up to 7 days (vs. 14 days for IV) 1
• Reconstitute with 3.2 mL of 1.0% lidocaine HCl (without epinephrine) 1
• Use reconstituted IM solution within 1 hour 1
• Inject deeply into large muscle mass (gluteal or lateral thigh) 1

Important Clinical Considerations

When to Consider Alternative Carbapenems

For septic shock or critically ill patients, consider switching to meropenem, doripenem, or imipenem/cilastatin with extended infusion strategies rather than ertapenem. 3

• Meropenem 1 g every 6 hours by extended infusion 3
• Doripenem 500 mg every 8 hours by extended infusion 3
• Imipenem/cilastatin 500 mg every 6 hours by extended infusion 3

Spectrum Limitations

• Ertapenem has limited activity against Pseudomonas aeruginosa, Acinetobacter species, and enterococci 4, 5
• Less suitable for late-onset nosocomial infections where these organisms are common 4
• Excellent for polymicrobial infections involving Enterobacteriaceae and anaerobes 5

Pharmacodynamic Considerations

• Ertapenem achieves MIC90 ≤1 mcg/mL against susceptible Enterobacteriaceae, streptococci, MSSA, and anaerobes 6
• Free drug concentrations remain above MIC for at least 8 hours post-infusion 6
• In critically ill patients or those with BMI >20 kg/m², standard dosing may not provide adequate tissue concentrations; consider shortened dosing intervals or continuous infusion 4

Monitoring Parameters

• Monitor for clinical response and resolution of sepsis markers 3
• Serum creatinine for dose adjustment calculations (use Cockcroft-Gault equation) 1
• If infection persists beyond recommended treatment duration, pursue further diagnostic evaluation 3