Pharmaceutical retailers in Bangladesh face serious operational and financial difficulties as a result of poor inventory management, which frequently leads to critical stockouts of essential medications and high carrying costs for non-essential items. Ad hoc, experience-based ordering is still common in the retail pharmacy industry, despite the theoretical establishment of scientific inventory control models. By creating and implementing an integrated inventory optimization framework in a top retail pharmacy chain in Bangladesh, this study fills this knowledge gap. Using a combination of ABC (Based on Annual Usage Value) and VEN (Vital, Essential, Non-essential) analysis, 1,012 medicine SKUs were thoroughly analyzed as part of the methodology. Our integrated matrix was able to identify 270 high-priority Category I items, which make up 26.7% of all SKUs but account for roughly 85.5% of all annual inventory expenditures.  Cost-optimal order quantities were then determined by carefully applying the Economic Order Quantity (EOQ) model to these crucial items. This quantitative analysis of the top 20 Category I items showed a significant discrepancy between the quantities required by the EOQ and the retailer's current ordering procedure.  The findings show that implementing the EOQ model would result in a noteworthy 30.32% cost efficiency gain, with the Total Inventory Cost (TIC) for these items alone being reduced by 26,834 BDT annually. According to the study's findings, retail pharmacies can improve their financial performance, guarantee the steady supply of necessary medications, and close the crucial gap between technical potential and operational practice in a cutthroat market by systematically integrating the ABC-VEN-EOQ model.