From the Research
Rhubarb juice can potentially increase the International Normalized Ratio (INR) in patients taking warfarin, which may increase bleeding risk. Patients on warfarin therapy should be cautious about consuming large amounts of rhubarb juice or adding it to their diet suddenly. Although there is no direct evidence in the provided studies that specifically addresses the effect of rhubarb juice on INR in patients taking warfarin, the general principle of drug interactions and dietary influences on warfarin therapy can be applied. Warfarin works by inhibiting vitamin K-dependent clotting factors, and compounds in certain foods or drugs may further disrupt this pathway, potentially enhancing its blood-thinning properties.
Key Considerations
- If a patient on warfarin wishes to consume rhubarb, they should do so consistently rather than intermittently, as sudden changes in consumption can cause unpredictable INR fluctuations.
- It's advisable for patients to inform their healthcare provider about any significant dietary changes, including rhubarb consumption, and they may need more frequent INR monitoring when introducing rhubarb into their diet.
- Small amounts of rhubarb occasionally are less likely to cause significant problems than regular large quantities.
Evidence Review
The most recent and highest quality study regarding drug interactions with warfarin is from 2021 1, which systematically reviews drug-drug interactions with warfarin, focusing on patient-important clinical outcomes. However, this study does not specifically mention rhubarb or its effect on INR. Other studies provided focus on different aspects of warfarin management and do not directly address the question of rhubarb's effect on INR in patients taking warfarin 2, 3, 4, 5.
Clinical Decision
Given the lack of direct evidence, the decision to consume rhubarb juice should be made with caution, considering the potential for increased bleeding risk due to the interaction with warfarin's anticoagulant effect. Patients should be advised to maintain consistent consumption patterns and inform their healthcare providers of any dietary changes to ensure appropriate monitoring and adjustment of their warfarin therapy as needed.