Which antiemetic is indicated for the prevention of nausea associated with radiation therapy?

The correct answer is ondansetron, which is a 5-HT3 receptor antagonist specifically indicated for the prevention of nausea and vomiting associated with chemotherapy, radiation therapy, and surgery. Ondansetron works by blocking the action of serotonin, a neurotransmitter that can trigger nausea and vomiting. Its effectiveness in managing nausea due to radiation therapy makes it a preferred choice for patients undergoing treatments that expose them to radiation.

In the context of radiation therapy, ondansetron is often utilized because it has a favorable side effect profile and provides effective symptom relief in patients at risk for nausea. This makes it a suitable option in the management plan for individuals receiving radiation.

Metoclopramide, while it has antiemetic properties and also addresses gastric motility, is not typically the first-line agent for radiation-induced nausea. Granisetron, similar to ondansetron, is also a 5-HT3 antagonist that can be effective but may be less commonly selected for certain radiation therapy protocols compared to ondansetron. Promethazine, an antihistamine with antiemetic effects, is more often indicated for nausea related to motion sickness or postoperative nausea rather than specifically for radiation therapy.