alosetron vs granisetron
Side-by-side comparison of alosetron and granisetron Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.
Lotronex
Kytril
Alosetron (Lotronex) is a medicine for women with severe diarrhea-predominant irritable bowel syndrome (IBS). It helps to reduce diarrhea and stomach pain.
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.
Alosetron is used to treat severe diarrhea-predominant irritable bowel syndrome (IBS) in women. It is for women whose IBS symptoms have lasted for 6 months or longer. You should have already ruled out other possible causes of your symptoms. This medicine is only for you if other treatments have not worked well enough.
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.
Alosetron blocks a substance called serotonin in your gut. Serotonin can speed up bowel movements. By blocking serotonin, alosetron slows down your bowel and reduces diarrhea.
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.
- • Constipation
- • Abdominal discomfort and pain
- • Nausea
- • Gastrointestinal discomfort and pain
- • Headache
- • Constipation
- • Weakness or fatigue
- • Diarrhea
- • Abdominal pain
- Medicine not working 11
- Diarrhea 10
- Feeling sick to your stomach 8
- Using the medicine for something it's not approved for 7
- Stomach pain 6
- Feeling sick to your stomach 1,306
- Throwing up 755
- Fever with low white blood cell count 718
- Loose, watery stools 709
- Fever 641
Alosetron can cause serious gut problems, like ischemic colitis (reduced blood flow to the bowel) and severe constipation. These problems can lead to hospitalization, surgery, or even death. Stop taking alosetron right away if you get constipated or have symptoms of ischemic colitis, like bloody diarrhea or bad stomach pain. Call your doctor immediately.
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.
It is not known if alosetron can harm your unborn baby. Talk to your doctor if you are pregnant or plan to become pregnant. It is also not known if alosetron passes into breast milk. Talk to your doctor about the best way to feed your baby if you take alosetron.
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.
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How to Read This alosetron vs granisetron Comparison
alosetron is classified in the 5-HT3 Antagonist (IBS-D) drug class, while granisetron sits within the 5-HT3 Receptor Antagonist (Antiemetic) class. Drugs from different classes work through distinct mechanisms, so a head-to-head comparison illustrates trade-offs rather than equivalence. 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, alosetron has 42 submissions while granisetron has 4,129. 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 alosetron and granisetron — 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.