Is intramuscular administration of Invanz (meropenem) appropriate, and what are the recommended doses for adults and children?

Invanz Intramuscular Administration

Invanz (ertapenem, not meropenem) can be administered intramuscularly, but this is a critical distinction—the question appears to confuse Invanz with meropenem, which are different carbapenems with different administration routes.

Clarification of Drug Identity

• Invanz is the brand name for ertapenem, not meropenem 1
• Ertapenem is specifically approved for intramuscular administration, while meropenem is administered intravenously or intramuscularly in limited contexts 1
• The evidence provided focuses primarily on meropenem, which is marketed as Merrem or Meronem, not Invanz 2

Ertapenem (Invanz) Intramuscular Dosing

Adult Dosing

• Standard IM dose: 1 gram once daily for complicated intra-abdominal infections and other approved indications 1
• Ertapenem offers the advantage of once-daily dosing compared to other carbapenems that require multiple daily doses 1

Pediatric Dosing

• Children 3 months to 12 years: 15 mg/kg twice daily intramuscularly (maximum 1 gram/day) 1
• Children ≥13 years: 1 gram once daily (adult dosing) 1
• The twice-daily pediatric dosing differs significantly from the once-daily adult regimen 1

Meropenem Administration Routes (For Comparison)

• Meropenem is NOT routinely given intramuscularly in most clinical guidelines 1
• Meropenem is primarily administered intravenously by bolus injection (over 5 minutes) or infusion (15-30 minutes) 3, 2
• Limited evidence supports intramuscular meropenem use in specific tuberculosis treatment protocols at 600-800 mg daily 1
• For severe infections, meropenem requires intravenous administration at 1-2 grams every 8 hours 1, 4

Clinical Considerations

When to Choose Ertapenem (Invanz) IM

• Community-acquired complicated intra-abdominal infections in non-critically ill patients where once-daily dosing is advantageous 1
• Patients requiring carbapenem therapy but lacking reliable intravenous access 1
• Step-down therapy from IV meropenem when continued parenteral therapy is needed but outpatient administration is desired 4

When Ertapenem is INADEQUATE

• Pseudomonas aeruginosa infections: Ertapenem lacks antipseudomonal activity; meropenem IV is required 1, 4
• Critically ill patients with healthcare-associated infections: Require broader-spectrum IV carbapenems like meropenem 1, 4
• Central nervous system infections: Ertapenem does not achieve adequate CNS penetration; meropenem 2 grams IV every 8 hours is required for meningitis 4
• Carbapenem-resistant organisms: Require high-dose meropenem with extended infusion, not ertapenem 4

Common Pitfalls to Avoid

• Do not confuse Invanz (ertapenem) with meropenem—they have different spectra of activity and administration requirements 1, 2
• Do not use ertapenem for Pseudomonas coverage—it is inactive against this pathogen 1
• Do not use intramuscular administration for critically ill or hemodynamically unstable patients—intravenous access is mandatory for reliable drug delivery 1
• Do not assume once-daily dosing applies to all carbapenems—only ertapenem has this pharmacokinetic profile 1