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.
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.
