Compare Kytril vs. Zofran

Granisetron (Kytril) and ondansetron (Zofran) are both antiemetic medications used to prevent nausea and vomiting caused by chemotherapy and radiation therapy. However, they differ in several ways. Granisetron is available as an oral tablet and intravenous infusion, while ondansetron comes in oral tablets, orally disintegrating tablets (ODT), oral solution, and injection forms. Granisetron is typically taken once or twice daily on treatment days, whereas ondansetron is taken every 8 to 12 hours. Ondansetron is also FDA-approved for preventing nausea and vomiting after surgery, which is not an approved use for granisetron. Granisetron is available only as a generic, while ondansetron is available as a lower-cost generic and offers more formulation options for those who have trouble swallowing pills. Common side effects of both medications include headache and constipation, but ondansetron may also cause fatigue and dizziness. Both medications can interact with other drugs that affect serotonin levels, increasing the risk of serotonin syndrome, and they can also affect heart rhythm, so it's important to discuss your full medication list with your healthcare provider.