Tehran University of Medical Sciences Journal of Pharmaceutical Care 2322-4630 13 4 2025 12 31 245 252 Mina Borran Department of Internal Medicine, Clinical Research Development Unit, Hajar Hospital, Shahrekord University of Medical Sciences, Shahrekord, Iran Seyyed Taha Yahyavi Department of Psychiatry, School of Medicine, Tehran University of Medical Sciences, Tehran,Iran. Khatereh Mirzaei Department of Biomedical Science, University of East London (UEL), London, United Kingdom Maryam Mousavi Department of Public Health, Glenala Education Company, London, United Kingdom 2025 05 23 2025 11 22 Background: Urinary tract infections (UTIs) are often misdiagnosed and inappropriately treated in psychiatric hospitals, largely due to challenges in patient communication, polypharmacy, and limited access to infectious disease specialists. In a psychiatric hospital setting in Tehran, Iran, ciprofloxacin was frequently prescribed despite guideline warnings, leading to a pharmacist-led intervention aimed at improving antimicrobial stewardship. This study aimed to evaluate the effectiveness of implementing a standardized urinary tract infection (UTI) treatment protocol, designed and supervised by a clinical pharmacist, on improving diagnostic accuracy and antibiotic prescribing in a psychiatric hospital setting. Methods: This before–after study was conducted at Roozbeh Hospital over a six-month period. In phase one, urinary tract infection treatments were initiated without pharmacist consultation. In phase two, a mandatory pharmacist-led protocol was implemented based on the Infectious Diseases Society of America (IDSA) and Journal of the American Medical Association (JAMA) guidelines. Data on urine culture rates, antibiotic selection, dosage accuracy, and treatment appropriateness were compared across both phases. Results: A total of 94 patients were included — 34 in phase I and 60 in phase II. Urine culture request rates improved from 26.5% to 95% (P < 0.001), reflecting adherence to the new protocol rather than case complexity. Correct antibiotic selection increased significantly (P = 0.004), with fosfomycin replacing ciprofloxacin as the preferred agent. High-dose errors decreased from 29.4% to 8.3% (P = 0.02), and unnecessary treatment of asymptomatic bacteriuria declined from 23.5% to 2% (P < 0.01). Conclusion: Pharmacist-led interventions improved diagnostic precision and antibiotic use in this psychiatric setting, suggesting a critical role for clinical pharmacists in antimicrobial stewardship, particularly in resource-limited mental health facilities. https://jpc.tums.ac.ir/index.php/jpc/article/view/849 https://jpc.tums.ac.ir/index.php/jpc/article/download/849/436