Skullcap and Fondaparinux Injection: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fondaparinux Injection
Skullcap
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
Theoretically, if skullcap is taken with an anticoagulant, excessive bleeding may occur. Flavonoid components of skullcap exhibited anti-platelet aggregation activity in rats, with some constituents having activity equal to or greater than that of aspirin1. Caution is advised.
Why it happens (mechanism)
Inhibition of platelet aggregation and the conversion of fibrinogen to fibrin by skullcap
Literature reports
1 report — tap to read
a) Flavonoids isolated from Scutellariae radix (skullcap) inhibited platelet aggregation induced by various substances in rats. Aspirin 1 millimole (mmol) inhibited collagen-induced platelet aggregation by 21.6%, whereas the same concentration of flavonoids oroxylin A, skullcapflavone II, wogonin, chrysin, baicalein, baicalin, and wogonin-7-O-D-glucuronide inhibited platelet aggregation by 43.8%, 32.5%, 24.7%, 23.4%, 23.3%, 12.4%, and 8.9%, respectively. Arachidonic acid induced platelet aggregation was inhibited by aspirin 1 mmol by 30.4%; whereas 1 mmol of baicalein, wogonin, and baicalin inhibited platelet aggregation by 47.7%, 45.5%, and 31.3%, respectively. Baicalein and baicalin inhibited the thrombin-induced conversion of fibrinogen to fibrin 1.
Common questions
Can I take Skullcap and Fondaparinux Injection together?
Increased risk of bleeding Always confirm with your pharmacist or prescriber before making any change.
How serious is the Skullcap and Fondaparinux Injection 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 "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Skullcap or Fondaparinux Injection 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 (1)
- Kubo M, Matsuda H, Tani T, et al: Studies on Scutellariae radix. XII. Anti-thrombic actions of various flavonoids from Scutellariae radix. Chem Pharm Bull 1985; 33:2411-2415. PubMed
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