Metopimazine sulfoxide is primarily used in the pharmaceutical industry as an intermediate in the synthesis of metopimazine, an antiemetic medication. It plays a crucial role in the production process, ensuring the final drug is effective in treating nausea and vomiting, particularly in conditions like chemotherapy-induced nausea or postoperative recovery. Its application is significant in enhancing the purity and efficacy of the active pharmaceutical ingredient, contributing to better therapeutic outcomes for patients.