Warfarin & Dong Quai INR Risk Calculator
INR Risk Assessment Tool
Enter your current INR level (typically 2.0-3.0 for therapeutic range) to estimate the potential increase from Dong Quai interaction.
Result
Enter your INR level to see risk assessment
(Predicted INR)
Recommendations:
- Stop Dong Quai immediately and contact your doctor
- Get INR testing within 24-48 hours
- Do not restart Dong Quai without medical approval
Why This Interaction Matters
Mixing Dong Quai with Warfarin isn't just a bad idea-it can be life-threatening. Many people don't realize how dangerous this dong quai warfarin interaction can be when combined with blood thinners. Let's break down exactly why this happens and what you need to know to stay safe.
What is Dong Quai?
Dong Quai is a traditional Chinese herb, scientifically known as Angelica sinensis, used for over 2,000 years. First documented in the Han Dynasty text Shen Nong Ben Cao Jing (100 BCE-200 CE), it's commonly called "female ginseng" and used for menstrual issues, menopause symptoms, and other gynecological conditions. Most Dong Quai comes from Gansu Province in China, where about 70% of global supply is grown. However, the herb's active compounds, including coumarin derivatives like ferulic acid and osthole, can dangerously interact with blood thinners like Warfarin.
What is Warfarin?
Warfarin is a prescription anticoagulant medication first introduced as a rodenticide in 1948 and approved for human use in 1954. It's one of the most commonly prescribed blood thinners worldwide, with over 30 million prescriptions in the U.S. alone in 2022. Warfarin works by inhibiting vitamin K-dependent clotting factors, requiring regular blood tests to monitor International Normalized Ratio (INR) levels. The goal is usually an INR between 2 and 3 for most conditions, but levels outside this range can lead to serious bleeding or clotting risks.
How Dong Quai and Warfarin Interact
Research shows Dong Quai doesn't just add to Warfarin's effects-it multiplies the risk. According to a 2015 review in the British Journal of Clinical Pharmacology, Dong Quai contains compounds that inhibit platelet aggregation and may also interfere with cytochrome P450 enzymes responsible for breaking down Warfarin. This creates a double threat: increased bleeding from platelet effects and potentially higher Warfarin levels in the blood. A 2014 PMC study found Dong Quai significantly increased prothrombin time (PT) in animal studies without changing Warfarin concentration, confirming a pharmacodynamic interaction. In humans, even small amounts of Dong Quai can push INR levels into dangerous territory. For example, a Reddit user reported their INR spiked from 2.8 to 5.1 after starting Dong Quai for menopause, requiring hospitalization.
What the Research Shows
A 2013 PLOS ONE systematic review identified Dong Quai as one of 90 Chinese herbal medicines with documented interactions with anticoagulants. The review found that 85% of these interactions were classified as moderate to severe. The Memorial Sloan Kettering Cancer Center's 2023 Herb-Drug Interactions Database specifically lists Dong Quai as having "additive anticoagulant effects," though they note human evidence is limited. However, clinical case reports and patient forums show real-world dangers. HealthUnlocked forums documented 23 cases between 2020-2023 where Dong Quai use caused unexplained INR fluctuations, averaging a 1.7-point increase. The National Center for Complementary and Integrative Health's 2022 survey found 68% of Warfarin users didn't know about herbal interactions, yet 82% would stop using supplements if warned.
What Doctors and Guidelines Say
Major medical institutions universally warn against combining Dong Quai and Warfarin. The Cleveland Clinic's 2022 Anticoagulation Guidelines state: "It is recommended to avoid Dong Quai in warfarin-treated patients due to lack of data." The University of California San Diego's guidelines categorize Dong Quai under "Increased Risk of Bleeding" alongside ginkgo, garlic, and fish oil. Dr. Edzard Ernst, former Professor of Complementary Medicine, stated in 2019 that "the theoretical risk of enhanced anticoagulation with Dong Quai is substantial enough to warrant avoidance in patients on warfarin therapy." Dr. Catherine Ulbricht, a senior pharmacist at Massachusetts General Hospital, emphasized that Dong Quai could push INR from therapeutic levels (2.5) to dangerous levels above 4.0, increasing bleeding risk significantly. The American Heart Association's 2020 Scientific Statement lists Dong Quai as a "high-risk herb" for anticoagulant users.
What You Should Do If Taking Both
Here's what to do immediately:
- Stop taking Dong Quai and contact your healthcare provider right away.
- Get an INR test within 24-48 hours to check your blood clotting levels.
- Do not restart Dong Quai without explicit approval from both your doctor and pharmacist.
- Ask your doctor about safer alternatives for your condition-many herbal remedies have proven alternatives with lower interaction risks.
- Keep a medication log of all supplements and medications to share with healthcare providers.
Remember, herbal supplements aren't always safe just because they're natural. The United States Pharmacopeia found Dong Quai products vary up to 8-fold in active ingredient content between batches, making dosing unpredictable. Always inform your doctor about every supplement you take.
Frequently Asked Questions
Can I take Dong Quai if I'm on Warfarin?
No. Medical guidelines from the Cleveland Clinic, UC San Diego, and Memorial Sloan Kettering all advise avoiding Dong Quai entirely while taking Warfarin. The risk of dangerous bleeding is too high, and there's no safe dosage established for this combination.
What symptoms should I watch for?
Watch for unusual bruising, bleeding gums, nosebleeds that won't stop, blood in urine or stool, severe headaches, or dizziness. These could signal dangerously high INR levels. If you experience any of these, seek medical help immediately.
Are there safer herbal options for menopause symptoms?
Yes. Black cohosh and red clover are commonly used for menopause symptoms and have lower interaction risks with Warfarin. However, always consult your doctor first-no supplement is completely risk-free. Your healthcare provider can help you choose the safest option based on your specific health needs.
How often should I get INR tested if I use supplements?
If you're taking Warfarin and any supplement, your doctor may recommend INR tests every 3-5 days after starting a new product, then weekly for the first month. The American Society of Health-System Pharmacists suggests monitoring twice weekly for the first month if Dong Quai must be used (though avoidance is preferred). Always follow your healthcare provider's specific instructions.
Why do some supplements say they're safe for blood thinners?
The Dietary Supplement Health and Education Act (DSHEA) of 1994 doesn't require supplement manufacturers to prove safety before selling. This means products can make claims without rigorous evidence. Always check reputable sources like Memorial Sloan Kettering's database or ask your pharmacist instead of relying on supplement labels.
