Warfarin with Dong Quai Interaction Details
Brand Names Associated with Warfarin
- Coumadin®
- Jantoven®
- Warfarin
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
Nov 07, 2023
Interaction Effect
Increased risk of bleeding
Interaction Summary
One patient taking dong quai with warfarin presented with excessive bruising and an International Normalized Ratio (INR) of 10, within 1 month of beginning dong quai; another patient taking dong quai with warfarin presented with an INR of 4.9 yet was asymptomatic . In a study of 96 patients, intravenous dong quai significantly prolonged prothrombin time compared with dextran . Dong quai contains coumarin derivatives and components that may inhibit platelet aggregation .
Severity
Moderate
Onset
Delayed
Evidence
Probable
How To Manage Interaction
Caution is advised if dong quai and an anticoagulant are taken concomitantly. Monitor for signs and symptoms of excessive bleeding.
Mechanism Of Interaction
Inhibition of thromboxane formation and platelet aggregation by coumarin derivatives in dong quai
Literature Reports
A) A 46-year-old female taking warfarin 5 mg daily, digoxin 0.25 mg daily, and furosemide 20 mg daily for atrial fibrillation had an international normalized ratio (INR) between 2 and 3 for more than two years and remained in good health. She presented to an anticoagulation clinic with a prothrombin time (PT) of 23.5 seconds and INR of 4.05, but was asymptomatic. She denied dietary changes, illnesses, or other medication use. One month later, her PT was 27.0 seconds and her INR had increased to 4.9. She again denied any changes in diet or medications, but did state that she had started taking dong quai (Nature's Way) 565 mg once or twice daily for perimenopausal symptoms. She was instructed to discontinue dong quai, and two weeks later her PT was 21.6 and her INR was 3.41. After another two weeks had passed, her PT and INR were 18.5 and 2.48, respectively .
B) In a study of 96 patients with acute ischemic stroke admitted to a Chinese hospital, 200 milliliters (mL) of an extemporaneously prepared 25% RAS (dong quai from the dried root of Radix Angelicae Sinensis: RAS) solution was administered intravenously for 20 days to 50 patients and dextran was administered to 46 controls. The prothrombin times (PT) were significantly (p less than 0.0001) longer in patients administered RAS than in patients receiving dextran, although specific PT values were not provided. Dextran can inhibit platelet aggregation, and prolong both bleeding and coagulation times .
C) A 1-month regimen of dong quai (dose unspecified) provoked extensive bruising and an International Normalized Ratio (INR) of 10 after being given concomitantly with warfarin to a menopausal woman (age unspecified). The patient had previously taken warfarin for 10 years following a mitral valvuloplasty .
Warfarin Overview
-
Warfarin is used to prevent blood clots from forming or growing larger in your blood and blood vessels. It is prescribed for people with certain types of irregular heartbeat, people with prosthetic (replacement or mechanical) heart valves, and people who have suffered a heart attack. Warfarin is also used to treat or prevent venous thrombosis (swelling and blood clot in a vein) and pulmonary embolism (a blood clot in the lung). Warfarin is in a class of medications called anticoagulants ('blood thinners'). It works by decreasing the clotting ability of the blood.
Return To Our Drug Interaction Homepage
Feedback, Question Or Comment About This Information?
Ask Dr. Brian Staiger, PharmD, our medical editor, directly! He's always more than happy to assist.
Definitions
Severity Categories
Contraindicated
These drugs, generally, should not be used together simultaneously due to the high risk of severe adverse effects. Combining these medications can lead to dangerous health outcomes and should be strictly avoided unless otherwise instructed by your provider.
Major
This interaction could result in very serious and potentially life-threatening consequences. If you are taking this drug combination, it is very important to be under close medical supervision to minimize severe side effects and ensure your safety. It may be necessary to change a medication or dosage to prevent harm.
Moderate
This interaction has the potential to worsen your medical condition or alter the effectiveness of your treatment. It's important that you are monitored closely and you potentially may need to make adjustments in your treatment plan or drug dosage to maintain optimal health.
Minor
While this interaction is unlikely to cause significant problems, it could intensify side effects or reduce the effectiveness of one or both medications. Monitoring for changes in symptoms and your condition is recommended, and adjustments may be made if needed to manage any increased or more pronounced side effects.
Onset
Rapid: Onset of drug interaction typically occurs within 24 hours of co-administration.
Delayed: Onset of drug interaction typically occurs more than 24 hours after co-administration.
Evidence
Level of documentation of the interaction.
Established: The interaction is documented and substantiated in peer-reviewed medical literature.
Theoretical: This interaction is not fully supported by current medical evidence or well-documented sources, but it is based on known drug mechanisms, drug effects, and other relevant information.
How To Manage The Interaction
Provides a detailed discussion on how patients and clinicians can approach the identified drug interaction as well as offers guidance on what to expect and strategies to potentially mitigate the effects of the interaction. This may include recommendations on adjusting medication dosages, altering the timing of drug administration, or closely monitoring for specific symptoms.
It's important to note that all medical situations are unique, and management approaches should be tailored to individual circumstances. Patients should always consult their healthcare provider for personalized advice and guidance on managing drug interactions effectively.
Mechanism Of Interaction
The theorized or clinically determined reason (i.e., mechanism) why the drug-drug interaction occurs.
Disclaimer: The information provided on this page is for informational purposes only and should not be considered medical advice. Always consult with a qualified healthcare professional regarding your specific circumstances and medical conditions.
Where Does Our Information Come From?
Information for our drug interactions is compiled from several drug compendia, including:
The prescribing information for each drug, as published on DailyMED, is also used.
Individual drug-drug interaction detail pages contain references specific to that interaction. You can click on the reference number within brackets '[]' to see what reference was utilized.
The information posted is fact-checked by HelloPharmacist clinicians and reviewed quarterly.