Pharmacology · Class
Carbapenems !
The broadest β-lactams, kept for serious hospital infections and ESBL-producing bacteria; they can lower valproate levels.
Updated 2026-11-01
What they are
A group of β-lactams (meropenem, imipenem with cilastatin, ertapenem) that resist most β-lactamases, including extended-spectrum β-lactamases (ESBL). They cover gram-positive, gram-negative and anaerobic bacteria and are a key reserve for multidrug-resistant infections, so their use is carefully restricted.
Mechanism of action
Like other β-lactams, they acylate the active-site serine of penicillin-binding proteins and stop the cross-linking of peptidoglycan; the weakened wall bursts. Their structure makes them stable to most β-lactamases. Killing depends on the time the free drug stays above the MIC, which is why prolonged infusions are sometimes used.
Target: Penicillin-binding proteins (bacterial transpeptidases)
Drugs in this class
- MeropenemA broad-spectrum intravenous carbapenem for serious hospital infections, intra-abdominal sepsis and meningitis; it can…Penicillin-binding proteins (bacterial transpeptidases)
- Imipenem–cilastatinA very broad carbapenem paired with cilastatin, which stops the kidney from destroying it; it carries the highest…Penicillin-binding proteins (bacterial transpeptidases)
- ErtapenemA once-daily carbapenem for community infections and ESBL producers; unlike meropenem it does not cover Pseudomonas or…Penicillin-binding proteins (bacterial transpeptidases)
- Meropenem–vaborbactamMeropenem paired with vaborbactam, a β-lactamase inhibitor that protects it from KPC carbapenemases; reserved for…KPC carbapenemase (vaborbactam) and penicillin-binding proteins (meropenem)
Others in the class
- doripenem
- imipenem–cilastatin–relebactam
Test yourself
Think of the answer, then tap the question to see it.
A patient whose epilepsy is controlled with valproic acid needs a carbapenem. What is the risk?
The carbapenem lowers valproate levels quickly and can cause breakthrough seizures; another antibiotic class is usually chosen.
Why is imipenem combined with cilastatin?
Cilastatin blocks renal dehydropeptidase I in the proximal tubule, which would otherwise break down imipenem.
Which important organisms does ertapenem fail to cover?
Pseudomonas aeruginosa, Acinetobacter and enterococci (and, like all carbapenems, MRSA).
Which enzyme family destroys carbapenems?
Carbapenemases, such as KPC and the metallo-β-lactamases.
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 58 (McGraw Hill, 2023); DailyMed - MEROPENEM injection, powder, for solution (DailyMed (U.S. National Library of Medicine), 2026); DailyMed - IMIPENEM AND CILASTATIN- imipenem and cilastatin sodium injection, powder, for solution (DailyMed (U.S. National Library of Medicine), 2026); DailyMed - ERTAPENEM- ertapenem sodium injection (DailyMed (U.S. National Library of Medicine), 2026).
Spotted a mistake?We are always improving for the community. Tell us what is wrong and our team will review it.Report a mistake
Representative model, for educational purposes only.