What is an example of a 5HT3 receptor antagonist?

Granisetron is a well-known example of a 5HT3 receptor antagonist. This class of medication is primarily known for its effectiveness in preventing and treating nausea and vomiting, particularly those caused by chemotherapy and radiation therapy. By blocking the serotonin receptors (5HT3) in the gastrointestinal tract and the central nervous system, granisetron helps to alleviate the feelings of nausea that can often accompany cancer treatments.

In the context of oncology, it is especially important because managing nausea and vomiting can significantly improve a patient's quality of life during treatment. Granisetron is often preferred due to its efficacy and minimal side effects compared to other antiemetics.

Other options listed serve different purposes; for instance, Aprepitant is a neurokinin-1 receptor antagonist, Olanzapine is an atypical antipsychotic that can also help with nausea but does not primarily act as a 5HT3 antagonist, and Promethazine is an antihistamine that has antiemetic properties but does not specifically target the 5HT3 receptor.