Tehran University of Medical Sciences Journal of Pharmacoeconomics and Pharmaceutical Management 2383-4498 11 1 2025 09 26 45 56 EN Mohammad Mahdi Raeis zadeh Department of Pharmacoeconomics and Pharmaceutical Administration, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Fatemeh Soleymani Department of Pharmacoeconomics and Pharmaceutical Administration, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran Anahita Bineshian Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran Daryush Talei Faculty of Pharmacy, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran Maryam Shiehmorteza Department of Clinical Pharmacy, Faculty of Pharmacy, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran 2025 03 05 2025 05 04 Background:  Health systems must continuously adapt and undergo reforms in both structure and function to effectively meet the evolving needs of society and respond to changing conditions. Due to the importance of the role of drug studies in rationalizing the pattern of drug use, the current study was based on the anatomical therapeutic chemical (ATC) classification system and the defined daily dose (DDD) developed by World Health Organization (WHO). Methods:  This study is a retrospective, cross-sectional, descriptive-analytical analysis of injectable antibiotic prescriptions at Bu-Ali Hospital from 2012 to 2017. Data were extracted from the Hospital Information System (HIS), focusing on injectable antibiotics administered and consumed during hospital stays. The Kolmogorov-Smirnov test was used to assess data normality, and the paired t-test was applied to compare the periods before and after the implementation of the HTP. The Wilcoxon signed-rank test was also used for paired group comparisons. Results: Following the implementation of the HTP, all investigated indicators include total number, DDD and cost showed a significant increase compared to the pre-HTP period. Only the cost per capita (p-value=0.712) and amount per capita (p-value =0.182) of total injectable antibiotics decreased post-HTP, though this change was not statistically significant. Conclusion: The HTP in Iran significantly influenced antibiotic prescription patterns at Bu-Ali Hospital, leading to increased usage of injectable antibiotics and DDD. These changes improved access to potent antibiotics, but continued monitoring is necessary to ensure responsible usage and prevent antimicrobial resistance. https://jppm.tums.ac.ir/index.php/jppm/article/view/252 https://jppm.tums.ac.ir/index.php/jppm/article/download/252/166