Drug Utilization Evaluation of Colistin: A Retrospective Study

Background: Colistin, is used as the last treatment line for infections concluded from multiple drug-resistant gram-negative microorganisms. Increased consumption of colistin leads to resistance to this antibiotic in many countries. This study investigated the usage pattern of colistin administration in a selected hospital in Iran. Methods: This study was conducted in a selected hospital in Ahvaz. Inclusion criteria were all patients who received colistin during this time according to the health information system. Patients who were received less than three doses of colistin were excluded from the study. Prescription of colistin in all patients was evaluated according to the protocol extracted from the last version of Lexicomp written by Wolters Kluwer. The descriptive and analytical statistics were carried out by the R software. Results: Among 27 patients who received colistin, pneumonia (30%) was the main diagnoses. Colistin administration was based on the microbiological culture data in 70% of cases. Considering the involved microorganism, most cases were Acinetobacter spp., followed by Klebsiella spp. Loading dose was prescribed for seven (26%) patients. In only five (19%) cases, colistin dosing, including loading dose, maintenance dose, and the interval of colistin administration, was appropriate during the study time. Increasing in serum creatinine was seen in two (7.4%) patients. In 29.4% of patients, the combination of colistin and carbapenems was observed. Conclusion: Given the lack of appropriate dose adjustment of colistin that may lead to incidence of resistance and adverse effect, applying of the specialist clinical pharmacist will be suggested.