Does cherry juice interact with warfarin? (3+ interaction)

This article will answer the question, “Does cherry juice interact with warfarin?”. Along with some research studies to support our discussion. We will discuss the specific foods and drinks that should be avoided while taking warfarin medication. Additionally, we will discuss safe and effective ways to use warfarin. 

Does cherry juice interact with warfarin? 

Yes, cherry juice may interact with warfarin. Cherry contains a small amount of vitamin K and a large quantity of vitamin C, which interacts with warfarin. Cherry can decrease the effectiveness of warfarin and increase the risk of bleeding. It is safe to consume cherry juice in small amounts. However, if consumed in a larger quantity, it can increase the level of vitamins K and C in your body. (1)

Warfarin is a blood-thinning agent used to prevent blood clots that can block blood vessels and cut blood supply to a particular part of the body. Warfarin inhibits vitamin K epoxide reductase complex 1 (VKORC1) enzyme and prevents activation of vitamin K. (2)

Vitamin K is an important factor in blood coagulation as it activates coagulating factors and proteins C and S, which are essential for blood clotting. Vitamin K also plays an important role in bone metabolism and other physiological functions. Increased blood levels of vitamin K can decrease the effectiveness of warfarin and increase the risk of complications. (2,3)

What does the research suggest? 

In a review article, 15 case reports and 7 controlled trials were analysed, which revealed that fruits like cranberry, pomegranate juice, avocado, grape juice, mango, and papain were found to interact with warfarin. (4)

100g of cherry contains 7mg of vitamin C and 2.1mcg of Vitamin K. A 65-year-old woman was admitted to the emergency room with complaints of chest pain, shortness of breath, nausea and diaphoresis Upon examination, they found that she had an acute pulmonary embolism and deep venous thrombosis. (5,6)

She was then treated with warfarin 5mg and enoxaparin 60mg. Her INR levels were below the target level; hence, warfarin was increased to 20mg. She was taking vitamins and ascorbic acid (vitamin C) supplements for vitamin deficiency. When ascorbic acid was discontinued, her INR value reached 15.4, which is extremely high. Finally, the study concluded that ascorbic acid (vitamin C) was the culprit in decreasing the action of warfarin. (6)

Anticoagulant instability was seen due to a change in the intake of vitamin K in patients with long-term oral anticoagulants. This can be avoided with careful intake of a vitamin K-rich diet and multivitamins. (7)

How do vitamins K and C affect warfarin activity?

Vitamin C can decrease the effectiveness of warfarin due to its chelating properties and its effect on the gastric mucosa. Decreased warfarin action can increase the chances of blockage, which can lead to stroke and other life-threatening conditions. (6)

Vitamin K is a cofactor that plays an important role in blood clotting. Warfarin, on the other hand, is an anticoagulant that prevents the clotting of blood. Anticoagulant therapies are used to prevent thrombosis, embolism and MI in patients who are at a greater risk. (2,3)

Whenever an anticoagulant therapy is initiated, the International Normalised Ratio (INR) should be maintained in the range of 2-3. However, with excess vitamin K and C intake, the action of warfarin decreases, and a change in INR is seen. Maintaining an INR of 2-3 is important to prevent the risk of life-threatening conditions. (8)

Research studies have shown that increased baseline plasma concentrations of vitamin K led to a slow rise in INR value, and consuming more vitamin K-rich diets or supplements (>250mcg per day) can decrease sensitivity to warfarin and lead to warfarin resistance. (1)

What dietary intake should be avoided while on warfarin therapy? 

There are certain diet restrictions which need to be followed while on warfarin therapy to avoid the risk of complications. Vitamin K and C are necessary to carry out bodily functions, but an excess amount of vitamin K and C during warfarin therapy can affect the action of warfarin and can increase the risk of complications. 

It is important to monitor the amount of dietary intake of vitamins while on warfarin therapy to avoid complications. Reduced intake of vitamin C can also cause vitamin deficiency. Hence, it is important to maintain a balanced diet. 

How to use warfarin safely and effectively? 

Using warfarin safely and effectively involves following proper instructions, such as:

• Always take the dose of warfarin as prescribed by your physician. 
• Do not change or stop taking the dose of warfarin without consulting your physician. 
• Warfarin requires frequent monitoring, especially INR. Attend all scheduled appointments to ensure proper assessment of your treatment. 
• Maintain a consistent intake of vitamins K and C. Do not consume a large amount of food and fruits, such as pineapple, spinach, avocado, etc., which can interact with warfarin. 
• OTC drugs such as cold medication, supplements and herbal products can interact with warfarin and increase the risk of bleeding. 
• Avoid taking multivitamins and ascorbic acid supplements, as they can increase the plasma concentration of vitamin K and decrease the action of warfarin. 
• The use of warfarin comes with a risk of increased bleeding. Look out for any bruises and avoid activities which can put you at a greater risk of bleeding. 
• Limit the use of alcohol and tobacco as it can interfere with warfarin and its metabolism. 
• Consult your physician if you notice any unwanted changes while on warfarin treatment. 

In my experience 

According to my knowledge and experience as a pharmacist, warfarin can interact with a variety of foods, such as pineapple, avocado, spinach, and cherries. Since cherry contains a high amount of vitamin C and a small quantity of vitamin K, excess intake of cherry in any form can decrease the effectiveness of warfarin and put you at risk of stroke or myocardial infarction. 

Have a discussion with your physician or dietician about the possible interaction between warfarin and food. 

References