cimetidine 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 cimetidine 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 which are OAT3 substrates (e.g., cefaclor, cimetidine, ciprofloxacin, penicillin G, ketoprofen, furosemide, methotrexate, zidovudine) may be increased.
Tagamet
Arava
Cimetidine (Tagamet) reduces stomach acid. It is used to treat ulcers, heartburn, and other conditions where too much acid is produced.
Leflunomide is a drug that can help reduce the symptoms of rheumatoid arthritis. It works by slowing down the body's immune system.
Cimetidine treats active duodenal ulcers for short periods. It can also be used long-term at a lower dose to prevent ulcers from returning. This medicine also treats active benign gastric ulcers for a short time. Additionally, it can help with erosive gastroesophageal reflux disease (GERD), which damages the esophagus.
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.
Cimetidine is an H2 receptor antagonist. This means it blocks histamine from attaching to certain cells in your stomach. By blocking histamine, cimetidine reduces the amount of acid your stomach makes.
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.
- • Headache
- • Dizziness
- • Diarrhea
- • Diarrhea
- • Respiratory infection
- • Nausea
- • Headache
- • Rash
- Chronic Kidney Disease 1,264
- Acute Kidney Injury 710
- Renal Failure 694
- Nausea 681
- Fatigue 598
- Rheumatoid Arthritis 24,923
- Pain 20,055
- Arthralgia 16,941
- Joint Swelling 15,567
- Fatigue 15,384
Reversible confusional states (like mental confusion, agitation, or hallucinations) have been reported, mostly in severely ill patients. These usually appear within 2-3 days of starting treatment and clear up within 3-4 days of stopping the drug.
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.
Tell your doctor if you are pregnant or plan to become pregnant. The effects of cimetidine during pregnancy are not fully known. Talk to your doctor about the risks and benefits of taking cimetidine while breastfeeding.
Do not take leflunomide if you are pregnant. It can cause birth defects. If you are breastfeeding, you should stop while taking this medicine.
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How to Read This cimetidine vs leflunomide Comparison
cimetidine is classified in the H2 Receptor Antagonist 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 split between OTC and prescription status, which affects access and supervision.
Adverse event totals above are pulled from the FDA's Adverse Event Reporting System (FAERS). For these top-ranked reactions alone, cimetidine has 3,947 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 blocks a transport system that normally helps remove cimetidine from your body. this causes cimetidine levels in your blood to increase.. 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 cimetidine or leflunomide.
Registry boundary: This comparison displays source-record fields and does not provide individualized medical direction.