Ertapenem is a parenteral, broad-spectrum, 1-beta-methyl carbapenem antibiotic. It is structurally similar to meropenem but has a longer half-life, allowing for once-daily administration. It is effective against a wide range of Gram-positive and Gram-negative aerobic and anaerobic bacteria, including many Extended-Spectrum Beta-Lactamase (ESBL)-producing organisms, but lacks activity against Pseudomonas aeruginosa and Acinetobacter species. It is a critical agent in the Indian hospital setting for managing moderate to severe community-acquired and mixed infections.
Adult: 1 gram administered once daily by intravenous infusion over 30 minutes or by intramuscular injection.
Note: IV: Reconstitute 1g vial with 10 mL of Water for Injection, NaCl 0.9%, or Bacteriostatic Water for Injection. Shake well. Further dilute in 50 mL of NaCl 0.9% ONLY. Infuse over 30 minutes. DO NOT use dextrose (D5W) as diluent. IM: Reconstitute 1g vial with 3.2 mL of 1% lidocaine HCl injection (without epinephrine). Shake thoroughly. Administer by deep intramuscular injection into a large muscle mass. Do not administer IV. IM and IV solutions are NOT interchangeable.
Ertapenem exerts bactericidal activity by inhibiting bacterial cell wall synthesis. It has a high affinity for Penicillin-Binding Proteins (PBPs), particularly PBP-2 in Gram-negative bacteria and PBP-1, PBP-2, and PBP-3 in Gram-positive bacteria. Binding to these enzymes inhibits the final transpeptidation step of peptidoglycan synthesis, leading to osmotic instability and cell lysis.
Pregnancy: Pregnancy Category B (US FDA). Animal studies show no direct harm, but no adequate, well-controlled studies in pregnant women. Use only if clearly needed, weighing benefits against risks. Should be prescribed by a specialist.
Driving: May cause dizziness, headache, or somnolence. Patients should be cautioned about operating machinery or driving until they know how the drug affects them.
| Probenecid | Competitively inhibits renal tubular secretion of ertapenem, increasing its plasma concentration and half-life. Coadministration is not recommended. | Major |
| Valproic Acid / Divalproex Sodium | Ertapenem significantly reduces serum valproic acid levels (by up to 90%), leading to loss of seizure control. Avoid concomitant use. Use alternative antibiotics or anticonvulsants. | Major |
| Other seizure threshold-lowering drugs (e.g., Theophylline, Fluoroquinolones) | Increased risk of seizures. Monitor closely. | Moderate |
| Warfarin | Potential for increased INR due to altered gut flora and possible effects on vitamin K. Monitor INR closely. | Moderate |