Imipenem-cilastatin dosage

Imipenem is a more common cause of seizures than other beta-lactam antibiotics, particularly when high doses are given (13-15). In one study, seven of 21 children developed seizure activity while receiving imipenem + cilastatin for bacterial meningitis, a recognized risk factor (13). However, computer-assisted monitoring of imipenem + cilastatin dosages in relation to renal function resulted in a reduced incidence of seizures (16). 

The safety profile of the carbapenems is comparable to that of other beta-lactam antibiotics, in particular with regard to laboratory abnormalities, the most common ones being those related to liver function (3,4). In patients with pre-existing nervous system disease or who take dosages above the recommended limits (for example in renal impairment) seizures appear to be more common with imipenem + cilastatin. 

Imipenem is hydrolyzed by a dipeptidase found in the brush border of the proximal tubule. To prolong drug activity, imipenem is combined with cilastatin, an inhibitor of the dehydropeptidase the combined formulation is available as primaxin. Both imipenem and cilastatin have a t 2 of 1 hour. When administered with cilastatin, 70% of administered imipenem is recovered in the urine as the active drug. Dosage should be reduced for patients with renal insufficiency. 

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