Question

Imipenem,a newer antibiotic with a broad antibacterial spectrum, is co administered with cilastatin. Which of the following is the best reason for the same?

• A. Combination of antibiotics is synergistic against Pseudomonas specie
• B. Cilastatin aids gastrointestinal absorption of active moiety, imipenem
• C. Cilastatin inhibits beta=lactamase enzyme destroying imipenem
• D. Cilastatin inhibits an enzyme in kidney destroying imipenem

Answer 1

The Correct Option is D

Imipenem is an antibiotic with a broad antibacterial spectrum, effective against a wide range of bacteria. However, when administered alone, it is rapidly degraded in the kidneys by an enzyme called renal dehydropeptidase I. This degradation reduces the efficacy of imipenem by lowering its concentration in the body.

To prevent this, imipenem is co-administered with cilastatin. Cilastatin is a specific inhibitor of renal dehydropeptidase I, the enzyme responsible for breaking down imipenem in the kidneys. By inhibiting this enzyme, cilastatin prevents the degradation of imipenem, thus maintaining adequate levels of the antibiotic in the body to exert its therapeutic effect.

The combination of imipenem with cilastatin ensures that imipenem remains active and effective for a longer duration, enhancing its antibacterial efficacy without being prematurely inactivated. Therefore, the best reason for co-administering imipenem with cilastatin is to inhibit the enzyme in the kidney that would otherwise destroy imipenem, ensuring optimal therapeutic action of the antibiotic.