metopimazine + ondansetron

Metopimazine + ondansetron is a combination of two antiemetic drugs used primarily to prevent and treat nausea and vomiting, especially in patients undergoing moderately emetogenic chemotherapy. Metopimazine is a phenothiazine derivative that acts as a selective dopamine D2 receptor antagonist with peripheral selectivity, while ondansetron is a selective serotonin 5-HT3 receptor antagonist. The combination leverages the complementary mechanisms of action—blocking both dopaminergic and serotonergic pathways involved in emesis—to provide superior control over both acute and delayed chemotherapy-induced nausea and vomiting compared to either agent alone. Clinical studies have shown this regimen to be highly effective, with mild side effects such as constipation being the most notable adverse event[1][3][4][6].