Imipenem-Cilastatin sodium hydrate

Clinical Use

Antibacterial agent

Drug interactions

Potentially hazardous interactions with other drugs
Antiepileptics: reduced valproate concentration - avoid.
Antivirals: convulsions reported with concomitant administration of ganciclovir and valganciclovir.
Ciclosporin: variable reports of increase / no change in ciclosporin levels, and of neurotoxicity.

Metabolism

When administered alone, imipenem is metabolised in the kidneys by dehydropeptidase-I, an enzyme in the brush border of the renal tubules, to inactive, nephrotoxic metabolites, with only about 5 to 40 or 45% of a dose excreted in the urine as unchanged active drug. Cilastin inhibits the metabolism of imipenem. When given with cilastatin about 70% of an intravenous dose of imipenem is recovered unchanged in the urine within 10 hours. Cilastatin is also excreted mainly in the urine, the majority as unchanged drug and about 12% as N-acetyl cilastatin. Less than 1% of imipenem is excreted via the bile in the faeces.