What are the indications and dosing guidelines for ertapenem?

Ertapenem: Indications and Dosing Guidelines

Ertapenem is indicated for moderate to severe infections at a standard adult dose of 1 gram once daily, with specific indications including complicated intra-abdominal infections, complicated skin and skin structure infections, community-acquired pneumonia, complicated urinary tract infections, and acute pelvic infections. 1

Approved Indications

Ertapenem is FDA-approved for the following infections when caused by susceptible bacteria:

• Complicated intra-abdominal infections (5-14 days treatment)
• Complicated skin and skin structure infections, including diabetic foot infections without osteomyelitis (7-14 days treatment)
• Community-acquired pneumonia (10-14 days treatment)
• Complicated urinary tract infections including pyelonephritis (10-14 days treatment)
• Acute pelvic infections including postpartum endomyometritis, septic abortion, and post-surgical gynecologic infections (3-10 days treatment) 1
• Prophylaxis of surgical site infection following elective colorectal surgery (single 1g dose given 1 hour prior to surgical incision) 1

Antimicrobial Spectrum

Ertapenem has excellent activity against:

• Enterobacteriaceae, including ESBL-producing strains 2, 3
• Most anaerobes 4, 5
• Streptococci, including S. pneumoniae 5
• Methicillin-susceptible Staphylococcus aureus (MSSA) 5
• Haemophilus influenzae and Moraxella catarrhalis 5

Notably, ertapenem lacks activity against:

• Pseudomonas aeruginosa
• Acinetobacter species
• Methicillin-resistant staphylococci
• Enterococci 2

This antimicrobial profile makes ertapenem particularly suitable for community-acquired infections but less appropriate for hospital-acquired infections where resistant pathogens are common.

Standard Dosing Guidelines

Adults and Children ≥13 years:

• Standard dose: 1 gram IV or IM once daily 1
• Duration: Typically 5-14 days depending on infection type 2
• Administration:
  • IV infusion over 30 minutes
  • May be administered IM when appropriate 1

Children 3 months to 12 years:

• Standard dose: 15 mg/kg IV or IM twice daily (not to exceed 1 g/day) 1

Special Populations

Renal Impairment (Adults):

• CrCl >30 mL/min/1.73 m²: No dosage adjustment needed
• CrCl ≤30 mL/min/1.73 m² (severe impairment): 500 mg daily
• End-stage renal disease (CrCl ≤10 mL/min/1.73 m²): 500 mg daily 1

Hemodialysis Patients:

• If administered within 6 hours prior to hemodialysis: 150 mg supplementary dose following hemodialysis session
• If administered ≥6 hours prior to hemodialysis: No supplementary dose needed 1

Hepatic Impairment:

• No specific dose adjustments recommended 1

Clinical Applications

Intra-abdominal Infections

Ertapenem (1g once daily) is particularly recommended for patients with inadequate/delayed source control or at high risk of infection with community-acquired ESBL-producing Enterobacterales 4. It's considered an alternative to piperacillin-tazobactam for complicated intra-abdominal infections 2.

Necrotizing Skin Infections

For mixed infections involving necrotizing skin, fascia, and muscle, ertapenem (1g every 24h IV) is recommended as monotherapy 4.

Septic Shock

In patients with septic shock due to biliary tract infections, carbapenems including ertapenem may be considered, though other carbapenems (meropenem, doripenem, imipenem/cilastatin) are often preferred when Pseudomonas coverage is needed 4.

Administration Considerations

• Do not mix or co-infuse with other medications
• Do not use diluents containing dextrose
• IV administration: Must be reconstituted and diluted prior to administration
• IM administration: Reconstitute with 1.0% lidocaine HCl injection (without epinephrine) 1
• The once-daily dosing makes ertapenem convenient for outpatient parenteral antimicrobial therapy 2

Important Cautions

• Use ertapenem only for proven or strongly suspected bacterial infections to reduce the development of drug-resistant bacteria 1
• Consider local epidemiology and susceptibility patterns when selecting empiric therapy 1
• Ertapenem has limited stability (6-12 hours depending on concentration) at room temperature, which may affect administration scheduling 2
• Contraindicated in patients with known hypersensitivity to product components or history of anaphylactic reactions to β-lactams 1

Ertapenem's once-daily dosing, broad spectrum against common community-acquired pathogens, and activity against ESBL-producing organisms make it a valuable option for treating moderate to severe infections, particularly when outpatient therapy is desired or when ESBL-producing organisms are suspected.