metopimazine + ondansetron + prednisolone

This is a fixed-dose combination of three pharmaceutical agents—metopimazine, ondansetron, and prednisolone—used as an antiemetic regimen. - Metopimazine is a phenothiazine derivative with potent and selective dopamine D2 and D3 receptor antagonist activity, providing antiemetic effects primarily through peripheral dopamine antagonism. It also exhibits antihistamine and anticholinergic properties but does not significantly cross the blood–brain barrier, reducing central side effects[3]. - Ondansetron is a selective serotonin 5-HT3 receptor antagonist that blocks serotonin both peripherally on vagal nerve terminals and centrally in the chemoreceptor trigger zone, preventing nausea and vomiting. - Prednisolone is a synthetic glucocorticoid corticosteroid with anti-inflammatory and immunosuppressive properties; its mechanism in emesis prevention may involve inhibition of prostaglandin synthesis or reduction of inflammation associated with chemotherapy-induced nausea. The combination has been studied for prophylaxis against chemotherapy-induced nausea and vomiting (CINV), particularly in patients receiving moderately emetogenic regimens for breast cancer. Clinical trials have shown that this three-drug regimen provides superior protection against delayed-phase nausea compared to two-drug combinations (ondansetron plus metopimazine), with generally mild side effects[2][1].