Imipenem-cilastatin Usage and Dosing

Imipenem-Cilastatin is a carbapenem with a broad spectrum of activity that includes:Aerobic and anaerobic gram-negative bacilli.Aerobic gram-negative bacilli that produce extended spectrum beta-lactamases (ESBLs).
Notable absence of activity vs. MRSA, E. faecium, Vancomycin-resistant enterococci, and Stenotrophomonas sp.In vitro MICs of Imipenem-cilastatin versus  Proteus , Providencia , and Morganella species are  higher than those of meropenem. MICs for both drugs are in the susceptible range .
Wide variety of FDA-approved indications.Because of its relative instability in solution, Imipenem is not suitable for outpatient prolonged infusion therapy.
Seizure risk is greater than for the other carbapenems.
Cilastatin present to block enzymatic degradation of Imipenem by dehydropeptidase on brush border of proximal convoluted tubule of the kidney.
For infection due to P. aeruginosa, increase Imipenem dose to 3 or 4 gm/day divided q8h or q6h. Prolonged infusion of carbapenems may be more efficacious and safer 

Meropenem susceptibility should not be relied upon as a surrogate to predict susceptibility to Imipenem.

Adult Dose

Usual Dose 0.5 gm IVq6h. P. aeruginosaDose1 gm q6–8h

Pediatric Dose

Imipenem is not recommended in children with CNS infections due to risk of seizures.Age > 28 Days :60-100 mg/kg/day (div q6-8h) (max 2–4 gm/day)