Ertapenem
Ertapenem sodium
Brand names:Invanz
A broad-spectrum carbapenem antibiotic historically used in TCCC for complicated combat wound infections and for casualties unable to take oral medications. Ertapenem's broad spectrum and once-daily dosing made it well-suited to prolonged field care, though its primary role has been superseded by ceftriaxone in current TCCC parenteral wound prophylaxis.
Pharmacology and Actions
Ertapenem inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins and disrupting peptidoglycan cross-linking. As a carbapenem, ertapenem is resistant to most beta-lactamases including extended-spectrum beta-lactamases (ESBLs), which gives it exceptionally broad coverage including many resistant gram-negative organisms. Spectrum includes most gram-positive cocci (except enterococcus and MRSA), gram-negative bacilli, and anaerobes. Activity against Pseudomonas aeruginosa is limited compared to other carbapenems.
Indications
- Complicated combat wound infections (historical TCCC parenteral option)
- Complicated intra-abdominal infections in austere environments
- Complicated skin and soft tissue infections
- Casualties unable to tolerate oral medications when ceftriaxone is unavailable
- Polymicrobial infection with anaerobic coverage requirements
Absolute Contraindications
- Known carbapenem or beta-lactam allergy with anaphylaxis history
- Severe renal impairment without dose adjustment
- Concurrent valproic acid use (significant drug interaction)
Precautions and Side Effects
Common adverse effects include infusion site reactions, diarrhea, nausea, and headache. Seizure risk is increased, particularly in patients with renal impairment or CNS disorders. Carbapenems can lower valproic acid levels significantly, precipitating seizures in patients on this medication. Cross-reactivity with penicillin allergy is approximately 1 percent for non-severe penicillin reactions; avoid in severe penicillin allergy with anaphylaxis history. Clostridioides difficile colitis can occur.
Adult Dosing
Pediatric Dosing
Pediatric dosing: 15 mg/kg IV/IM every 12 hours (maximum 1 gram per dose) for patients 3 months to 12 years. For patients 13 years and older, use adult dosing. Pediatric tactical use is uncommon; consult medical control.
Pharmacokinetics
Peak Effect: IV: end of infusion. IM: 2 hours after injection.
Duration: 24 hours (supports once-daily dosing)
Storage and Handling
Store powder vials at controlled room temperature (15 to 30 degrees Celsius). Protect from light. Reconstituted solution must be used within 6 hours at room temperature or 24 hours refrigerated.
Reconstitution:
Ertapenem is supplied as a 1 gram sterile powder vial. For IV infusion, reconstitute with 10 mL sterile water, NSS, or bacteriostatic water, then transfer to 50 mL NSS for infusion. For IM injection, reconstitute with 3.2 mL of 1 percent lidocaine (without epinephrine) and inject into a large muscle mass.
TCCC and TECC Role
Ertapenem was the historical TCCC parenteral wound antibiotic before ceftriaxone took primary position. The reasons for the shift include cost, supply chain considerations, the broader role of ceftriaxone in civilian EMS and hospital practice, and the recognition that ertapenem's carbapenem-class breadth is generally not required for empiric wound prophylaxis. Ertapenem retains a role in established polymicrobial wound infections, intra-abdominal infections, and as an alternative when broader coverage than ceftriaxone is needed in prolonged field care.
Ertapenem is the carbapenem that veterans of the Iraq and Afghanistan era will remember from older TCCC kits. The shift to ceftriaxone reflects practical considerations: ceftriaxone is more widely available, less expensive, and adequate for empiric wound prophylaxis. Ertapenem remains in many critical care transport kits and is the right drug when polymicrobial coverage with anaerobes is needed. The IM route with lidocaine reconstitution is operationally important when IV access is not available.
Using ertapenem for routine wound prophylaxis when ceftriaxone is available. Current TCCC doctrine specifies ceftriaxone as the parenteral wound antibiotic of choice; ertapenem is reserved for indications requiring carbapenem-class breadth. The other common error is co-administering with valproic acid, which can precipitously drop valproic acid levels and trigger breakthrough seizures.
This drug profile is provided as educational reference material for trained medical providers. It is not medical advice, not a substitute for formal training, and not a substitute for current published guidelines or medical direction.
Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances are subject to additional handling, accountability, and documentation requirements per DEA and state law. Always verify dosing, indications, contraindications, and route of administration against current published guidelines and your local protocols before administration.
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Penn Tactical Solutions publishes this reference for educational purposes. PTS does not provide medical direction and does not assume responsibility for clinical decisions made in the field. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Educational reference for trained medical providers. Not medical advice. Not a substitute for formal training, current published guidelines, or medical direction. Drug administration is governed by your scope of practice, agency standing orders, medical director protocols, and applicable state and federal regulations. Controlled substances require additional storage, accountability, and documentation per DEA and state law.
In a medical emergency, call 911. This reference is not a substitute for emergency medical services.
Verify dosing, indications, and contraindications against current published guidelines and your local protocols before administration. Confirm content currency against the source citation. Penn Tactical Solutions does not provide medical direction. Clinical responsibility rests with the administering provider, their medical director, and their agency.
Ertapenem
| IV/IO | TCCC historical: 1 gram IV once daily. Infuse over 30 minutes. Renal dose adjustment required for creatinine clearance below 30 mL/min. (Immediate after infusion) |
| IM | 1 gram IM once daily when IV access not available. Reconstitute with 1 percent lidocaine to reduce injection pain. Onset slower than IV. (30 to 60 minutes) |