(244) Flaxseed Interaction with Warfarin and Clopidogrel and The Potential Risk of Bleeding

Sunday, August 28, 2022

8:00 AM – 1:45 PM CEST

Location: Hall C

Publication Number: 1289

Presenting Author(s)

Waad Alghamdi
– Saudi Food and Drug Authority, Riyadh, Saudi Arabia

Co-Author(s)

Nouf Alfadel
– Saudi Food and Drug Authority (SFDA), Ar Riyad, Saudi Arabia
Fawaz F. Alharbi, MSc, PhD.
– Saudi Food & Drug Authority (SFDA), Saudi Arabia

Background: Flaxseed (Linum usitatissimum) is a herbal product, which contains approximately 55% alpha-linolenic acid (ALA). It is commonly used to improve digestive health or relieve constipation. Some studies suggest that flaxseed can decrease platelet aggregation and increase bleeding time.

Objectives: To assess the relatedness of the potential drug-herbal interaction between flaxseed and warfarin/clopidogrel as a part of drug –herbal interaction assessment project initiated by the Saudi Food and Drug Authority.

Methods: We conducted a systematic search in Embase, Cochrane, PubMed, and Google Scholar. Also, a search was performed in the Adis Insight database, and the Natural Medicines Database. The search included published work from inception to February 2022. Moreover, a search in the World Health Organization (WHO) database (VigiBase) was conducted in February 2022 to retrieve all reported cases worldwide of potential drug-herbal interaction between Flaxseed and Anticoagulants/antiplatelets. The assessment of interaction was performed by using the Drug Interaction Probability Scale (DIPs) tool.

Results: We found two published cases with flaxseed interaction. The cases were reported with warfarin and clopidogrel. The first case report was for clopidogrel and flaxseed interaction. A positive re-challenge was found between flaxseed oil and bruising intensity while taking clopidogrel. The second case described a warfarin and flaxseed interaction that increased international normalized ratio (INR) readings. The probability of interaction using the DIPS scale is probable for both cases. For the global cases retrieved from the WHO database, one case was the same published case for clopidogrel interaction with flaxseed. While the other global case was for a 49 years old male who was on warfarin for heart valve replacement. Concomitant products include flaxseed, ascorbic acid, and multivitamins. The interaction resulted in INR fluctuations.

Conclusions: The available evidence shows a possible pharmacodynamics interaction between flaxseed and warfarin/clopidogrel. Further assessment by well-designed pharmacoepidemiological studies is needed.