Heparin Injection and Dong Quai: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Heparin Injection
Dong Quai
No brand names on record
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased risk of bleeding
Interaction Deep Dive
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 quai3; another patient taking dong quai with warfarin presented with an INR of 4.9 yet was asymptomatic 1. In a study of 96 patients, intravenous dong quai significantly prolonged prothrombin time compared with dextran 2. Dong quai contains coumarin derivatives and components that may inhibit platelet aggregation 14.
Why it happens (mechanism)
Inhibition of thromboxane formation and platelet aggregation by coumarin derivatives in dong quai
Literature reports
3 reports — tap to read
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 1.
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 2.
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 3.
Common questions
Can I take Heparin Injection and Dong Quai together?
Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Heparin Injection and Dong Quai interaction?
It is rated moderate. Can be significant — usually manageable with monitoring.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
Questions for your pharmacist
- Does my dose of Heparin Injection or Dong Quai need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there anything you'd monitor while I'm on both?
References (4)
- Page RL & Lawrence JD: Potentiation of warfarin by dong quai. Pharmacotherapy 1999; 19:870-876. PubMed
- Junjie T & Huaijun H: Effects of Radix Angelicae Sinensis on hemorrheology in patients with acute ischemic stroke. J Tradit Chin Med 1984; 4:225-228.
- Ellis GR & Stephens MR: Minerva. BMJ 1999; 319:650.
- Ko FN, Wu TS, Liou MJ, et al: Inhibition of platelet thromboxane formation and phosphoionsitides breakdown by osthole from Angelica pubescens. Thromb Haemost 1989; 62:996-999.
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