alosetron vs leflunomide

PlainMeds reviewed this comparison against our methodology in August 2026. It places FDA and CMS record fields side by side, without recommending either medication.

Side-by-side comparison of alosetron and leflunomide. Data from FDA drug databases (Orange Book, NDC Directory, recalls, shortages) covering 20,000+ approved drugs, plus CMS pricing; see our methodology.

minor Known Drug Interaction

In patients taking leflunomide, exposure of drugs metabolized by CYP1A2 (e.g., alosetron, duloxetine, theophylline, tizanidine) may be reduced.

Drug Class
alosetron 5-HT3 Antagonist (IBS-D)
leflunomide Disease-Modifying Antirheumatic Drug (DMARD)
Type
alosetron Prescription
leflunomide Prescription
Summary
alosetron

Alosetron (Lotronex) is a medicine for women with severe diarrhea-predominant irritable bowel syndrome (IBS). It helps to reduce diarrhea and stomach pain.

leflunomide

Leflunomide is a drug that can help reduce the symptoms of rheumatoid arthritis. It works by slowing down the body's immune system.

What It Treats
alosetron

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.

leflunomide

Leflunomide treats active rheumatoid arthritis in adults. Rheumatoid arthritis is a disease that causes pain, swelling, and stiffness in the joints. This medicine can help reduce these symptoms.

How It Works
alosetron

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.

leflunomide

Leflunomide is a pyrimidine synthesis inhibitor. This means it blocks a certain process in your body. By blocking this process, it can reduce inflammation and slow down the damage to your joints.

Common Side Effects
alosetron
  • Constipation
  • Abdominal discomfort and pain
  • Nausea
  • Gastrointestinal discomfort and pain
leflunomide
  • Diarrhea
  • Respiratory infection
  • Nausea
  • Headache
  • Rash
FAERS Reports
alosetron
  • Diarrhoea 10
  • Nausea 8
  • Abdominal Pain 6
  • Death 6
  • Constipation 5
leflunomide
  • Rheumatoid Arthritis 24,923
  • Pain 20,055
  • Arthralgia 16,941
  • Joint Swelling 15,567
  • Fatigue 15,384
Serious Warnings
alosetron

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.

leflunomide

This drug can cause serious harm to an unborn baby. If you are pregnant or could become pregnant, you should not take this medicine. This drug can also cause serious liver problems. If you have liver problems, you should not take this medicine. Your doctor will monitor your liver with blood tests.

Pregnancy
alosetron

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.

leflunomide

Do not take leflunomide if you are pregnant. It can cause birth defects. If you are breastfeeding, you should stop while taking this medicine.

Also Compare, Nearby Drugs

How to Read This alosetron vs leflunomide Comparison

alosetron is classified in the 5-HT3 Antagonist (IBS-D) drug class, while leflunomide sits within the Disease-Modifying Antirheumatic Drug (DMARD) 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 35 submissions while leflunomide has 92,870. Those figures reflect cumulative reporting volume, not per-patient risk, so older, widely dispensed drugs typically look worse on count alone. These two drugs have a known minor interaction flagged in FDA labeling, attributed to leflunomide makes your body break down alosetron faster, which lowers the amount of medicine in your blood.. Serious warnings, pregnancy guidance, and contraindications can differ even when indications overlap.

A table cannot represent individual circumstances. Data here is sourced from FDA Structured Product Labels (SPL) and FAERS, both of which update as manufacturers and clinicians submit new information. This registry does not provide medical, treatment, substitution, or medication-change directions for alosetron or leflunomide.

Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.