Ertapenem Intramuscular Administration: Dosage and Frequency
Yes, ertapenem can be administered intramuscularly (IM) at a dose of 1 gram once daily, reconstituted with 1% lidocaine HCl injection (without epinephrine). 1, 2
Administration Guidelines
- Ertapenem IM is an FDA-approved route of administration with approximately 90% bioavailability compared to IV administration 1, 3
- The 1 gram once-daily dosing is appropriate for IM administration, with no accumulation observed after multiple daily doses 3
- Reconstitution must be done with 1% lidocaine HCl injection (in saline without epinephrine) to minimize injection site discomfort 1, 2
- Peak plasma concentrations (Cmax) are achieved in approximately 2.3 hours after IM administration 1
Clinical Applications
- IM ertapenem is particularly valuable when vascular access is limited or unavailable in emergency situations 4
- It has been successfully used as an alternative treatment for various infections including complicated intra-abdominal infections, skin infections, and urinary tract infections 2, 5
- A single dose of IM ertapenem 1g has been shown to be non-inferior to ceftriaxone in treating anogenital gonorrhea 4
- For multidrug-resistant tuberculosis treatment, IM ertapenem (with amoxicillin-clavulanate) has shown efficacy 4
Local Tolerability and Safety
- The most common local injection site symptoms are tenderness and pain, which are generally mild to moderate in severity 2
- In comparative studies, only 1.1% of patients receiving IM ertapenem experienced moderate to severe injection site symptoms, compared to 10% with IM ceftriaxone 2
- Systemic drug-related adverse events occur at similar rates to other parenteral antibiotics (approximately 16%) 2
Special Populations and Considerations
- No dosage adjustments are needed based on gender, age, weight, or liver disease 6
- Dose reduction is required for patients with advanced renal insufficiency (CrCl <31 mL/min/1.73 m²) 1
- For hidradenitis suppurativa, IM ertapenem has been used as a third-line therapy at 1g daily for a 6-week course 4
Important Caveats
- IM administration should be considered only when timely establishment of vascular access is not possible 4
- Intramuscular absorption and distribution in severe illness has not been extensively studied 4
- When treating sepsis or septic shock, IV administration is preferred if possible, but IM can be used if vascular access cannot be established 4
- For multidrug-resistant infections, always consider antimicrobial stewardship principles before using carbapenems 4
In summary, ertapenem 1 gram once daily administered intramuscularly (reconstituted with 1% lidocaine) is an effective alternative when IV access is challenging, with good bioavailability and tolerability compared to IV administration.