Palonosetron is a medication used to prevent nausea and vomiting caused by chemotherapy and surgery. It belongs to a class of drugs known as 5-HT3 receptor antagonists, which work by blocking the action of serotonin, a chemical in the body that can trigger these symptoms. This drug is typically administered as an injection and is known for its long-lasting effects, making it effective for both acute and delayed nausea. Palonosetron is often preferred due to its favorable safety profile and ability to provide relief for patients undergoing cancer treatment or surgical procedures.