granisetron vs ondansetron
Side-by-side comparison of granisetron and ondansetron Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Kytril
Zofran
Granisetron oral solution helps prevent nausea and vomiting caused by cancer treatments like chemotherapy and radiation. It belongs to a class of drugs called 5-HT3 receptor antagonists.
Ondansetron is a medicine that helps prevent nausea and vomiting. It is often used during cancer treatment or after surgery.
Granisetron is used to prevent nausea and vomiting. It is for people receiving cancer therapy that causes vomiting. This includes high doses of cisplatin, radiation, total body irradiation, and fractionated abdominal radiation.
This medicine is used to prevent nausea and vomiting. It can help if you are getting chemotherapy for cancer. It also helps with nausea and vomiting after surgery or radiation.
Granisetron blocks a natural substance called serotonin in the body. Serotonin can trigger nausea and vomiting. By blocking serotonin, granisetron helps prevent these side effects.
Ondansetron blocks a natural substance in your body called serotonin. Serotonin can cause nausea and vomiting. By blocking serotonin, ondansetron reduces these side effects.
- • Headache
- • Constipation
- • Weakness or fatigue
- • Diarrhea
- • Abdominal pain
- • Headache
- • Feeling tired
- • Constipation
- • Diarrhea
- Feeling sick to your stomach 1,306
- Throwing up 755
- Fever with low white blood cell count 718
- Loose, watery stools 709
- Fever 641
- Feeling sick to your stomach 11,557
- Feeling tired 8,201
- Loose, watery stools 7,793
- Throwing up 7,326
- Using the medicine for something it is not approved for 6,386
Granisetron can cause a heart problem called QT prolongation. Tell your doctor if you take other medicines that can also cause this issue, as it could lead to serious heart problems.
Ondansetron can cause heart problems like a prolonged QT interval. If you have congenital long QT syndrome, you should not take this medicine. Ondansetron can also cause Serotonin Syndrome, especially if you are taking other medicines for depression or pain. Seek immediate medical attention if you experience chest pain.
Tell your doctor if you are pregnant or breastfeeding. It is not known if granisetron will harm an unborn baby. It is also not known if granisetron passes into breast milk.
Talk to your doctor if you are pregnant or breastfeeding. It is not known if ondansetron will harm your unborn baby. Studies on the risk of birth defects are inconsistent.
Also Compare — Nearby Drugs
Compare granisetron with
Compare ondansetron with
How to Read This granisetron vs ondansetron Comparison
granisetron is classified in the 5-HT3 Receptor Antagonist (Antiemetic) drug class, while ondansetron sits within the 5-HT3 Receptor Antagonist (Antiemetic) class. Because both drugs share the same classification, they are often considered interchangeable in theory — but clinical outcomes rarely track that cleanly. Both drugs are prescription-only, so a licensed provider must authorize use.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, granisetron has 4,129 submissions while ondansetron has 41,263. Those figures reflect cumulative reporting volume — not per-patient risk — so older, widely dispensed drugs typically look worse on count alone. No direct interaction between these two drugs is listed in our FDA-derived dataset, though co-prescription still warrants pharmacist review. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.
A table cannot substitute for clinical judgment. Effectiveness, tolerability, drug-drug interactions with your other medications, kidney and liver function, pregnancy status, insurance formulary, and price all feed into a decision that only a licensed prescriber can make responsibly. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This page is for educational purposes only, is not medical advice, and should not be used to self-switch between granisetron and ondansetron — always consult your physician or pharmacist first.
Important: This comparison is for informational purposes only. Drug effects vary between individuals. Always consult your doctor or pharmacist for personalized medical advice.