This document discusses marketing strategies for pharmaceutical companies to retain market share after patent expiration, including reclassifying prescription drugs as over-the-counter (OTC). It analyzes sales data from four allergy drugs in Bulgaria before and after they were reclassified from prescription to OTC. All four drugs saw increases in sales after becoming available OTC, with one drug's sales increasing nearly threefold. However, sales trends varied between drugs, with cheaper options maintaining stronger sales growth over time. Reclassifying drugs to OTC can help companies extend brand viability and increase accessibility but must consider various stakeholder impacts.