Tropisetron is an antiemetic drug used to treat nausea and vomiting. It is used in cancer patients for chemotherapy- and radiotherapy-induced nausea and vomiting and for patients who have post-operative nausea and vomiting. Available as an oral or injectable drug, it requires a prescription from a doctor in most countries. Tropisetron is not currently available in the U.S. but is available in Europe and Australia and various other countries.
Tropisetron is known by various trade names, depending on the country and manufacturer. It belongs to the class of drugs called serotonin (5HT3) receptor antagonists. Other drugs in this class include ondansetron and granisetron. These, too, are known by various trade names worldwide.
Nausea and vomiting are caused by numerous factors, one of them being the release of serotonin. Tropisetron works by blocking the serotonin receptors in the stomach and, possibly, in the brain. This prevents the feeling of nausea and resultant vomiting. It has a relatively long duration of action, so is normally given as a once daily dose.
For chemotherapy-induced nausea, a common and debilitating side effect in cancer patients, tropisetron is usually given for six days, initially by injection on the first day, prior to chemotherapy, and then orally. It is usually taken in the morning, an hour before food. In cases where it does not control the nausea and vomiting, an adjunctive medication, such as a corticosteroid, may be prescribed by the attending medical practitioner.
Post-operative nausea and vomiting is also common, mainly as a side effect of anesthesia, and tropisetron may be given prophylactically. In this setting it is usually given as a single dose, by injection, prior to induction of anesthesia. It may also be used after surgery to treat nausea and vomiting.
As with any medication, tropisetron may interact with other medications, so concomitant drugs and diseases should be discussed with the prescriber. They should also be informed of pregnancy, desired pregnancy or lactation. Use of tropisetron with other drugs that may prolong the QTc interval, a cardiac effect, is not advised. Any cardiac history should be taken into consideration before using the drug.
In general, tropisetron is well tolerated. The most commonly reported side effect is headache. Other side effects, such as gastrointestinal ones like constipation, dizziness and fatigue have been reported, usually at higher doses. Driving and operating of heavy machinery while taking tropisetron should be avoided due to the possibility of it causing fatigue.