A drug used to prevent nausea and vomiting caused by cancer treatment. It is also used to prevent nausea and vomiting after surgery. Tropisetron blocks the action of the chemical serotonin, which binds to certain nerves and may trigger nausea and vomiting. Blocking serotonin may help lessen nausea and vomiting. It is a type of serotonin receptor antagonist and a type of antiemetic. It is not available in the United States.