anastrozole vs warfarin
Side-by-side comparison of anastrozole and warfarin. 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
7.3 Warfarin In a study conducted in 16 male volunteers, anastrozole did not alter the exposure (as measured by C max and AUC), and anticoagulant activity (as measured by prothrombin time, activated partial thromboplastin time, and thrombin time) of both R- and S-warfarin.
Recommendation: No special changes are typically needed, but you should continue your regular blood tests as directed by your doctor.
Arimidex
Coumadin, Jantoven
Anastrozole is a medicine used to treat breast cancer in women after menopause. It lowers estrogen levels in the body, which can help stop the growth of cancer cells.
Warfarin is a medicine that helps prevent blood clots. It is used to treat and prevent dangerous clots from forming in your body.
Anastrozole is used to treat breast cancer in women who have gone through menopause. It can be used as the first treatment for advanced breast cancer, or after other treatments like tamoxifen have stopped working. It is also used to lower the risk of breast cancer returning after surgery.
Warfarin is used to prevent and treat blood clots in your veins and lungs. It can also prevent clots if you have atrial fibrillation (irregular heartbeat) or a replacement heart valve. After a heart attack, it can lower the risk of death, another heart attack, or a stroke.
Anastrozole belongs to a class of drugs called aromatase inhibitors. It works by blocking an enzyme called aromatase, which the body uses to make estrogen. By lowering estrogen levels, anastrozole can slow or stop the growth of breast cancer cells that need estrogen to grow.
Warfarin works by blocking your body's use of vitamin K. Vitamin K is needed to make blood clotting factors. By blocking vitamin K, warfarin makes your blood less likely to clot.
- • Hot flashes
- • Weakness or fatigue
- • Arthritis
- • Pain
- • Joint pain
- • Bleeding from any tissue or organ
- Tiredness 3,255
- Joint pain 3,157
- Feeling sick to your stomach 2,647
- Hair loss 2,536
- Loose stools 2,266
- INR increased 10,275
- Shortness of breath 8,408
- Interaction with another medicine 6,289
- Tiredness 6,141
- Feeling sick to your stomach 5,921
Anastrozole may cause heart problems in women who already have heart disease. It can also weaken your bones, so your doctor may want to check your bone density. This medicine can harm an unborn baby, so use birth control while taking it and for 3 weeks after your last dose.
Warfarin can cause major or fatal bleeding. You must have your blood tested regularly (INR) while taking warfarin. Many things, like other medicines and diet changes, can affect your INR. Tell your doctor about any bleeding and follow their instructions to prevent bleeding.
Anastrozole can cause harm to an unborn baby. You should not take anastrozole if you are pregnant. Use effective birth control while taking anastrozole and for at least 3 weeks after your last dose. Do not breastfeed while taking anastrozole and for 2 weeks after the last dose.
Warfarin can harm your unborn baby, especially during the first three months of pregnancy. Do not take warfarin if you are pregnant, unless you have a mechanical heart valve and your doctor says the benefits outweigh the risks. Talk to your doctor if you are breastfeeding, and watch your baby for bruising or bleeding.
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How to Read This anastrozole vs warfarin Comparison
anastrozole is classified in the Aromatase Inhibitor drug class, while warfarin sits within the Vitamin K Antagonist (Anticoagulant) 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, anastrozole has 13,861 submissions while warfarin has 37,034. 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 research shows that this medicine does not interfere with how the blood thinner works or how much of it stays in your body.. 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 anastrozole and warfarin - 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.