Invanz (Ertapenem): Overview
Invanz (ertapenem) is a once-daily carbapenem antibiotic indicated for moderate-to-severe community-acquired infections including complicated intra-abdominal infections, complicated skin/soft tissue infections, community-acquired pneumonia, complicated UTIs, and acute pelvic infections. 1
Key Indications
FDA-approved uses 1:
- Complicated intra-abdominal infections (mild-to-moderate severity)
- Complicated skin and skin structure infections, including diabetic foot infections without osteomyelitis
- Community-acquired pneumonia (typical pathogens)
- Complicated urinary tract infections including pyelonephritis
- Acute pelvic infections (postpartum endomyometritis, septic abortion, post-surgical gynecologic infections)
- Surgical prophylaxis for elective colorectal surgery (adults only)
Guideline-Supported Uses
For mild-to-moderate community-acquired intra-abdominal infections, ertapenem is recommended as single-agent therapy alongside other options like cefoxitin, moxifloxacin, or tigecycline 2. However, important caution: the Expert Panel expressed concern that broad use of ertapenem may accelerate emergence of carbapenem-resistant Enterobacteriaceae, Pseudomonas, and Acinetobacter species 2.
For necrotizing skin/soft tissue infections (mixed polymicrobial), ertapenem 1g daily IV is an acceptable option, particularly for pediatric patients 3 months-12 years (15 mg/kg every 12h) 3, 4.
For community-acquired pneumonia due to Enterobacteriaceae (particularly K. pneumoniae), ertapenem 1g once daily showed equivalent efficacy to ceftriaxone 5.
Dosing
Adults 2, 1
- Standard dose: 1 gram IV or IM once daily
- Duration: Up to 14 days IV or 7 days IM
- Infusion time: 30 minutes for IV administration
- Surgical prophylaxis: 1 gram single dose given 1 hour prior to colorectal surgery
Pediatric (≥3 months) 2, 1
- Dose: 15 mg/kg twice daily (maximum 1 g/day)
- IV preparation: Reconstitute with 10 mL diluent, withdraw appropriate volume, dilute to ≤20 mg/mL
- IM preparation: Reconstitute with 3.2 mL 1% lidocaine (without epinephrine)
Renal Impairment 1
Critical adjustment: For creatinine clearance ≤30 mL/min/1.73 m², dose reduction is necessary. In hemodialysis patients, consider 1g three times weekly after dialysis 6.
Special Considerations
- Do NOT mix or co-infuse with other medications 1
- Do NOT use dextrose-containing diluents 1
- Loading dose: Always use a standard unitary dose as loading regardless of renal function, then adjust maintenance dosing 7
Contraindications 1
Absolute contraindications:
- Known hypersensitivity to ertapenem or anaphylactic reactions to β-lactams
- For IM administration only: Hypersensitivity to amide-type local anesthetics (due to lidocaine diluent)
Critical Warnings
Seizure Risk 1
Seizures occurred in 0.5% of patients during clinical trials. Highest risk in:
- Patients with CNS disorders (brain lesions, seizure history)
- Compromised renal function
- Inadequate dose adjustment for renal impairment
Management: Continue anticonvulsants in known seizure patients; initiate if seizures occur; consider dose reduction or discontinuation.
Valproic Acid Interaction 1
The concomitant use of ertapenem and valproic acid/divalproex sodium is generally NOT recommended. Carbapenems reduce valproic acid concentrations, increasing breakthrough seizure risk. Alternative antibiotics should be strongly considered for patients with well-controlled seizures on valproic acid 1.
Hypersensitivity 1
Serious anaphylactic reactions reported. Screen for prior β-lactam hypersensitivity before initiating therapy.
Clostridioides difficile 1
Evaluate for C. difficile if diarrhea develops during or after treatment.
Antimicrobial Spectrum 8, 9, 10
Excellent activity against:
- Enterobacteriaceae (including ESBL and AmpC producers)
- Penicillin-resistant S. pneumoniae
- Anaerobes (Bacteroides fragilis group)
- Most community-acquired gram-positive and gram-negative aerobes
NO activity against:
- Pseudomonas aeruginosa
- Acinetobacter species
- Methicillin-resistant staphylococci (MRSA)
- Enterococci
Clinical Pearls
Hypoalbuminemia concern: While ertapenem is 85-95% protein-bound, recent evidence suggests it remains effective in critically ill patients with hypoalbuminemia when MICs are favorable and source control is achieved 11. The 2024 IDSA guidance caution may be overstated—individualize based on patient factors rather than universally avoiding.
Stability limitations 7: Unlike other β-lactams, ertapenem has limited stability (6-12 hours at 25°C depending on concentration), requiring preparation close to administration time.
Safety profile 12: Generally well-tolerated with most common adverse events being diarrhea (5-5.6%), infused vein complications (3.2-4.5%), and nausea (2.5-3.4%)—comparable to piperacillin-tazobactam and ceftriaxone.
Antimicrobial stewardship: Reserve for appropriate indications to minimize carbapenem resistance development 13, 14. For ESBL-producing Enterobacterales in non-severe infections, ertapenem is preferred over meropenem/imipenem to preserve broader-spectrum carbapenems 13.