Ondansetron Hydrochloride USP (Dihydrate) API For CompoundingOndansetron USP (Dihydrate) is an active pharmaceutical ingredient (API) that is commonly used to prevent nausea and vomiting caused by chemotherapy, radiation therapy, and surgery. It belongs to a class of drugs known as serotonin 5 HT3 receptor antagonists and works by blocking the action of serotonin, a chemical in the body that can trigger nausea and vomiting. It is also sometimes used to prevent or treat nausea and vomiting associated with other