e.g. imipenem/cilastatin, meropenem, ertapenem, Carbapenems, particularly imipenem (Tienam) and meropenem,
Antibiotic of LAST RESORT
are our broadest-spectrum antibacterial drugs against most aerobic and anaerobic bacteria (Gram-positive and gram-negative) with the exception of occasional Pseudomonas strains.
They possess a beta-lactam ring and share the same mechanism of action of betal actams, but they are structurally unique and differ from both penicillins and cephalosporins.
Similar to those of other beta-lactams, but imipenem has a higher propensity to induce seizures. Minimize the risk by calculating appropriate doses for patients with renal dysfunction
- Very broad spectrum (G+ve and –ves, anaerobes) due to:
- Small molecules with charge characteristics that allow them to use porins in the OM of G-ve bacteria to access the PBPs
- Resistant to B lactamases
- Affinity to broad range of PBPs
- Imipenem is metabolized in the kidney to a nephrotoxic product. Cilastatin blocks the renal dehydropeptidase that catalyzes this reaction and prevents this metabolism from occurring.
Meropenem: + vabrobactam
The other drug of this group which is currently available. It does not undergo metabolism by renal dihydropeptidase enzyme.
Adverse effects
- Allergy: Carbapenems may rarely elicit an allergic reaction in patients with a history of penicillin allergy.
- Blood disorders.
- Neurotoxic in high doses .
- G.I.T: nausea, vomiting, etc.
Imipenem if given alone - combine w/ Cilastatin
is inactivated by renal dihydropeptidase so it’s combined with cilastatin which inhibits renal dihydropeptidase
CARBAPENEM / BETA-LACTAMASE INHIBITOR COMBINATIONS :
1-meropenem/vaborbactam 2- imipenem/cilastatin/relebactam