Abstract

Introduction Pharmacoepidemiology is a relatively new scientific topic, and it's the concepts, methods, and implications are in line with the observations of health studies in the past few decades. It involves the postmarketing investigations, drug utilization review, and the monitoring of both adverse drug reactions and the clinical efficacy of drugs. The Anatomical Therapeutic Chemical classification system as a drug classification method and the defined daily dose (DDD) as a measurement unit have been recommended by WHO for drug utilization studies. Patients and methods This was a prospective cross-sectional study. It was done using the Anatomical Therapeutic Chemical/DDD system and by calculating DDD per 100 bed-days (BDs) for four antibiotics, namely, vancomycin, metronidazole, ceftriaxone, and ceftazidime, used in 78 patients admitted in the internal medicine ICU ward in a hospital of Tehran University of Medical Sciences from April to October 2018. Results The DDD/100 BDs for ceftazidime, ceftriaxone, metronidazole, and vancomycin was 5.96, 4.17, 9.65, and 28.02, respectively. Conclusion Comparing the results of the current study with those of similar studies, it was found that the DDD/100 BDs for ceftazidime, ceftriaxone, and metronidazole is within the normal range, whereas that of vancomycin was much higher than normal.