Used primarily to prevent nausea and vomiting caused by cancer chemotherapy, especially effective in managing both acute and delayed symptoms following highly emetogenic treatments. Also utilized to prevent postoperative nausea and vomiting in surgical patients. Palonosetron is a selective serotonin 5-HT₃ receptor antagonist that blocks 5-HT₃ receptors in the central nervous system and gastrointestinal tract. Its long half-life allows for single-dose administration with prolonged effectiveness compared to other antiemetics. Commonly administered intravenously or orally before chemotherapy or anesthesia induction.