Background: A drug related problem is defined by the Pharmaceutical Care Network Europe Association as an an event or circumstance involving drug therapy that actually or potentially interferes with desired health outcomes. One critical aspect of preventing such errors is proper dose adjustment, which plays a vital role in the diagnosis and treatment of disease. For instance, adjusting the dose of warfarin based on the patient’s INR level is essential. In a 1995 study conducted in England, clinical pharmacists recommended target doses of angiotensin-converting enzyme (ACE) inhibitors for patients with chronic heart failure. As a result, patients experienced a significant reduction in pulmonary and peripheral edema, along with improved exercise test outcomes. At the Mongolian-Japanese Hospital of the Mongolian Medical University of Science and Technology, it is important to analyze dosage-related issues identified by clinical pharmacists and inform healthcare professionals about common dosage selection errors and associated risks. Aim: We analyzed issues related to medication dosage. Materials and Methods: A retrospective study was conducted to examine problem related to dosage detected through prescription monitoring at the Mongolian Japanese Hospital of the Mongolian National University of Health Sciences from 2023 to 2024. Results: Out of a total of 2340 drug-related problem identified across five inpatient wards during this period, 581 (100%) were related to dosage. Clinical pharmacists performed prescription review on approximately 67% of all inpatients, which was consistent between years. However, medication-related problems tended to decrease from 41.1% (n=1499) in 2023 to 22.3% (n=841) in 2024 (p=0.05). The majority of dose-related problems, 75.6% (n=440), were overdoses. Medication-related problems were most common in the surgical department, with 59.5% (n=346) (p=0.001). The most frequent dosage-related errors involved exceeding the daily dose of diclofenac, administering higher- than-recommended doses of ceftriaxone, failing to adjust cefotaxime for renal function, and using inappropriate doses of metronidazole in patients with impaired liver function. The leading cause of these errors was failure to adhere to guideline-recommended dosing, which accounted for 71.3% (n=415) of cases (p=0.001). When dosage-related recommendations were provided to physicians before of treatment, acceptance rates increased by 14% (p=0.001). These interventions resulted in an estimated cost saving of 1.267.219₮ and a reduction of 363 injections. Conclusion Therefore, clinical pharmacist-led prescription review can help reduce the risk of dosage errors, lower associated healthcare costs, and alleviate the burden on medical staff.