Can ertapenem (Intramuscular) (IM) be administered via the intramuscular (IM) route?

Intramuscular Administration of Ertapenem

Yes, ertapenem can be administered via the intramuscular (IM) route as an alternative to intravenous administration when vascular access is limited or unavailable. According to the FDA drug label, ertapenem may be administered intramuscularly for up to 7 days for appropriate infections 1.

Administration Guidelines

Approved Use

• Ertapenem 1g can be given once daily via IM injection 1
• The IM route should be reconstituted with lidocaine to reduce injection pain 2
• IM administration is limited to 7 days maximum, whereas IV administration can be used for up to 14 days 1

Bioavailability

• The relative bioavailability of IM ertapenem is approximately 92% compared to IV administration 3
• Plasma concentration profiles are comparable between IM and IV administration at later time points, though peak concentrations are somewhat lower with IM administration 3

Clinical Considerations

When to Consider IM Administration

• When vascular access is limited or difficult to establish 4
• In emergency situations where timely antimicrobial administration is critical 4
• As an alternative to IV administration for appropriate infections 1

Limitations and Precautions

• IM administration should be considered only if timely establishment of vascular access is not possible 4
• Intramuscular absorption and distribution in severe illness has not been extensively studied 4
• Proper injection technique is essential to avoid complications:
  • Use appropriate needle length to ensure delivery into muscle tissue
  • Avoid inadvertent subcutaneous injection
  • Rotate injection sites if multiple doses are required

Tolerability

• When reconstituted with lidocaine, IM ertapenem is generally well tolerated 2
• Common local injection site symptoms include tenderness and pain, which are typically mild 2, 5
• In comparative studies with IM ceftriaxone, ertapenem showed similar or better local tolerability profiles 2, 5

Special Populations

• For patients with renal impairment (CrCl ≤30 mL/min/1.73 m²), dose adjustment to 500 mg daily is required, regardless of administration route 1
• No specific dose adjustments are needed for elderly patients when using the IM route 5

Common Pitfalls to Avoid

1. Failing to reconstitute with lidocaine, which can lead to increased injection pain
2. Using improper injection technique, which may result in subcutaneous rather than intramuscular delivery
3. Administering IM ertapenem for longer than the 7-day maximum recommended period
4. Not considering the patient's coagulation status before IM administration
5. Forgetting to adjust dosing in patients with severe renal impairment

In emergency situations such as sepsis where prompt antimicrobial administration is critical, IM ertapenem can be a valuable alternative when IV access is challenging, helping to meet the recommendation for timely administration of appropriate antimicrobials 4.