Thursday June 22, 2006
Imipenem and Primaxin

Q: What advantage we have when we add cilastatin with Impenem ?

OR in other words, What is the difference between Imipenem and Primaxin (Imipenem plus Cilastatin) ?


A: Imipenem get metabolized in the kidneys by enzyme called dehydropeptidase I and cannot achive therapeutic level in urine. Addition of Cilastatin inhibit the enzyme in kidney's renal tubules so that when imipenem and cilastatin are given concomitantly, increased imipenem levels are achieved in the urine.

Bonus Pearl: Primaxin is hemodialyzable so dose may be unreliable in such patients or preferably should be given after hemodialysis session. Dose in dialysis dependent patient is either 250 mg q 12 hrs or 500 mg after each dialysis.


When Imipenem was introduced, it get reputed with nick name of "Jesus water" due to its broad coverage and to kill most bugs.