Evaluation of the appropriateness of imipenem/cilastatin prescription and dosing in a tertiary care hospital

BACKGROUND Imipenem/cilastatin is an antibacterial agent of the carbapenem class of β-lactams that is known to have an extremely wide spectrum of activity against Gram-positive, Gram-negative, aerobic, anaerobic, and even multidrug-resistant strains. The objective of this study was to evaluate the appropriate use of imipenem/cilastatin in a local tertiary care hospital. The study assessed the indication both empirically and after the culture results were available, the dose and dose adjustment in renal failure, as well as the incidence of seizure in hospitalized patients receiving imipenem/cilastatin. METHODS This observational study was conducted in a tertiary care hospital over a 3-month period. The treatment of 100 patients with imipenem/cilastatin was evaluated both empirically and after culture results were available. Analysis of the appropriateness of imipenem/cilastatin indication, dose, and monitoring of seizure frequency was based on the package insert, updated published guidelines, and clinical judgment. RESULTS Patients from internal medicine and intensive care units comprised approximately 50% of the population in the study. The patients received imipenem/cilastatin mainly for urinary tract infections (27%) or for sepsis of an unknown focus (22%). The use of imipenem/cilastatin empirically was appropriate in 97.2% (n=69/71) of the cases, and its use postculture in 86% of the cases. There were 29% of the patients who were not started on imipenem/cilastatin empirically. Four patients out of the 29 patients (13.8%) who were not started on imipenem/cilastatin empirically inappropriately received imipenem/cilastatin post-culture results. Thirty-three patients (33%) were not dosed appropriately, 30 of whom had renal impairment and creatinine clearance fluctuations. Only one patient developed a seizure while on imipenem/cilastatin. CONCLUSION The prescription of imipenem/cilastatin at our setting was mostly appropriate to what is recommended in the guidelines and the literature, although a few cases could have been managed better. Dosage adjustment, however, was not as appropriate, mainly in patients who did not have a stable creatinine clearance.