Can butterfly pea flower cause bleeding in individuals with bleeding disorders or those taking anticoagulants like warfarin?

Butterfly Pea Flower and Bleeding Risk

Butterfly pea flower (Clitoria ternatea) possesses blood platelet aggregation-inhibiting properties and should be avoided in individuals with bleeding disorders or those taking anticoagulants like warfarin due to the significant risk of potentiating bleeding complications. 1

Mechanism of Bleeding Risk

Clitoria ternatea has been scientifically documented to have platelet aggregation-inhibiting properties, which means it interferes with the blood's ability to clot normally 1. This antiplatelet effect operates independently of the INR (international normalized ratio) pathway that warfarin affects, creating a dual mechanism for increased bleeding risk when combined 2.

The plant contains multiple secondary metabolites including triterpenoids, flavonol glycosides, anthocyanins, and steroids that contribute to its pharmacological activities 1. These compounds can interact with anticoagulation pathways through mechanisms similar to other herbal products that affect warfarin therapy 3.

Clinical Implications for Anticoagulated Patients

For patients on warfarin, the combination of butterfly pea flower with anticoagulant therapy creates additive bleeding risk through two distinct pathways:

• Warfarin inhibits vitamin K-dependent clotting factors (II, VII, IX, X), measurable by INR elevation 4
• Butterfly pea flower inhibits platelet aggregation, which is not reflected in INR measurements but still increases bleeding risk 2, 1

This dual mechanism is particularly dangerous because the platelet inhibition from butterfly pea flower will not be detected by routine INR monitoring, potentially leading to unexpected bleeding events even when INR appears therapeutic 2, 5.

Evidence from Herbal-Warfarin Interactions

Multiple studies demonstrate that herbal remedies with antiplatelet or anticoagulant properties significantly increase bleeding risk when combined with warfarin 2, 3. A comprehensive review identified 58 different plants that may alter blood hemostasis and anticoagulation with warfarin, with the primary clinical outcome being increased bleeding risk 3.

The interaction between herbal products and warfarin is particularly concerning because:

• The complex chemical matrix of plants creates varied and unpredictable interactions 3
• Patients often do not disclose herbal use to healthcare providers 2
• Concomitant use of potentially interacting medicines was involved in the majority of warfarin-associated bleeding events reported to spontaneous reporting systems 5

Specific Risk Factors That Amplify Danger

Patients at highest risk for bleeding complications from this combination include those with:

• Advanced age (>65-75 years), which independently increases bleeding risk at any given INR level 4
• History of prior bleeding episodes, particularly gastrointestinal or intracranial 4
• Concomitant use of antiplatelet agents (aspirin, clopidogrel), which creates triple antithrombotic therapy 4
• Renal insufficiency or anemia, which impair hemostasis 4, 6
• Mechanical heart valves or atrial fibrillation requiring therapeutic anticoagulation 4

Clinical Recommendation

Butterfly pea flower should be strictly avoided in:

• All patients taking warfarin or other vitamin K antagonists 2, 3
• Patients on direct oral anticoagulants (DOACs) 4
• Patients with known bleeding disorders or thrombocytopenia 4
• Patients taking antiplatelet therapy (aspirin, clopidogrel, prasugrel) 4
• Patients with recent or planned surgical procedures 4

If a patient on anticoagulation has been consuming butterfly pea flower and develops bleeding:

• Immediately discontinue the herbal product 4, 2
• Check INR and complete blood count 4
• For major bleeding with elevated INR, administer 4-factor prothrombin complex concentrate (PCC) 25-50 U/kg IV plus vitamin K 5-10 mg by slow IV infusion 4
• Recognize that the platelet inhibition from butterfly pea flower will persist beyond INR correction and may require platelet transfusion if bleeding is severe 4

Critical Pitfall to Avoid

Do not assume that a therapeutic INR means the patient is safe from bleeding if they are consuming butterfly pea flower. The antiplatelet effects operate independently of the coagulation cascade and will not be reflected in INR measurements, creating a hidden bleeding risk that can manifest as unexpected hemorrhage even with "normal" laboratory values 2, 1.