Ertapenem

How it works

It inhibits bacterial cell wall synthesis by binding penicillin-binding proteins, and is stable to many beta-lactamases, giving a broad spectrum against Gram-positive and Gram-negative organisms.

Prescribing in practice

• There is a risk of cross-hypersensitivity with penicillins and other beta-lactams, so a careful allergy history is essential before use.
• Unlike some carbapenems it lacks reliable activity against Pseudomonas aeruginosa and Acinetobacter and enterococci, which limits its empirical use.
• Dose adjustment is required in significant renal impairment, and seizures have rarely been reported with carbapenems.

Monitoring

Monitor clinical response, renal function, and for hypersensitivity reactions, CNS effects such as seizures, and signs of antibiotic-associated colitis.

Counselling the patient

• Tell the team about any previous reaction to penicillins or other antibiotics.
• Report any severe or persistent diarrhoea.
• Report any new confusion, twitching or seizures.

Evidence & guidelines

Ertapenem is an established carbapenem option in UK antimicrobial guidance, with once-daily dosing supported by its pharmacokinetic profile.