Ertapenem, sold under the brand name Invanz, is a carbapenem antibiotic medication used for the treatment of infections of the abdomen, the lungs, the upper part of the female reproductive system, and the diabetic foot.

[7][8] The most common side effects include diarrhoea, nausea (feeling sick), headache, and problems around the area where the medicine is infused.

[5][7][10] Common side effects are diarrhoea (in 5% of people receiving ertapenem), nausea (in 3%) and vomiting, reactions at the injection site (5%, including pain and inflammation of the vein), and headache.

[10] Ertapenem can reduce the concentrations of valproic acid, an epilepsy medication, by 70% and perhaps up to 95% within 24 hours; this can result in inadequate control of seizures.

[18][19] Drug interactions via the cytochrome P450 enzyme system or the P-glycoprotein transporter are considered unlikely, as these proteins are not involved in the metabolism of ertapenem.

[14] It inhibits cross-linking of the peptidoglycan layer of bacterial cell walls by blocking a type of enzymes called penicillin-binding proteins (PBPs).

[10][14] Microorganisms can become resistant to ertapenem by producing carbapenemases, enzymes that inactivate the drug by opening the beta-lactam ring.

Similar to doripenem, meropenem and biapenem, ertapenem has slightly better activity against many Gram-negative bacteria than other carbapenems such as imipenem.

[23][24] Regarding pharmacokinetics, imipenem, doripenem and meropenem have lower plasma protein bindings (up to 25%) and shorter half-lives (about one hour) than ertapenem.