Granisetron is a drug used in the treatment of nausea and vomiting, particularly in those patients undergoing cancer chemotherapy. It works by reducing activity in the vagus nerve by acting on 5-HT3 receptors. Granisetron is available as an oral tablet, intravenous solution, and transdermal patch. Common side-effects of granisetron include dizziness, headache, and constipation; however, it is considered a well-tolerated medicine. There are no clinically significant interactions with this drug.