Granisetron is in a class of drugs known as serotonin 5HT3 receptor antagonists. It works by blocking serotonin activity in the chemoreceptor trigger zone. Granisetron is used for the prevention and management of chemotherapy-induced nausea and vomiting (CINV). A sustained-release formulation of granisetron was studied for its effects in patients with cancer and CINV. Because of the longer half life of this formulation, sustained-release granisetron may have improved efficacy for the prevention of delayed CINV.