[Poll] Can I take pomelos with warfarin?

 

Click Below to find out the answer:

Lack of clinical data 

There is no clinical data and trials on the effects of pomelo and/or it’s juice on warfarin and/or INR*.  

 

Clinical deduction 

Even though there is no direct clinical data, we can deduce the possible clinical effect between pomelo and warfarin. Pomelos are cousins to grapefruit. Both its juice and pulp are known to reduce the activity of certain enzymes in the liver in the same way as grapefruit. These enzymes are collectively known as the cytochrome P450 enzymes.  

Warfarin is removed from the body primarily through the cytochrome P450 enzymes. Therefore, we can assume that consuming pomelo can have similar effects to that of consuming grapefruit. It should reduce the enzyme activity that removes warfarin from the body. This results in an increased concentration of warfarin in the patient. This in turn will cause an increase in INR which means the patients’ blood may be thinner than intended. As a consequence, it may increase the risk of bleeding. 

On the other hand, there are studies on the possible interaction between grapefruit and warfarin. In a small trial of 16 patients, there is no increase in INR after consuming grapefruit juice. Another trial of 9 patients also concluded with the same results. However, these results are deemed inconclusive or unreliable due to small sample size. It is also notable that there are a couple of cases reported that showed increased INR and even bleeding after consuming grapefruit. 

 

Conclusion 

Since there is a possible food-drug interaction between pomelos and warfarin as explained above, it is advisable to avoid pomelos in a person taking warfarin. In the absence of more reliable clinical data, we are unable to recommend the consumption of pomelo with warfarin. It is better to be safe than sorry. 

However, for those who have already consumed pomelos during this festive season, do not worry. Avoid consuming pomelo from now on and monitor yourself for signs of bleeding. If there are signs of bleeding then you should consult your doctors as soon as possible. 

*INR: International Normalized Ratio: A measure of how thick or thin your blood is. The larger the number, the thinner the blood. 

 

 

References  

  1. Lexicomp Interaction [Internet]. Online.lexi.com. 2017 [cited 27 September 2017]. Available from: https://online.lexi.com/lco/action/interact 
  2. Egashira K. INHIBITORY EFFECTS OF POMELO ON THE METABOLISM OF TACROLIMUS AND THE ACTIVITIES OF CYP3A4 AND P-GLYCOPROTEIN. Drug Metabolism and Disposition. 2004;32(8):828-833. 
  3. Egashira K. INHIBITORY EFFECTS OF POMELO ON THE METABOLISM OF TACROLIMUS AND THE ACTIVITIES OF CYP3A4 AND P-GLYCOPROTEIN. Drug Metabolism and Disposition. 2004;32(8):828-833. 
  4. Bodiford A, Kessler F, Fermo J, Ragucci K. Elevated international normalized ratio with the consumption of grapefruit and use of warfarin. SAGE Open Medical Case Reports. 2013;1:2050313X1351160. 
  5. Sullivan D, Ford M, Boyden T. Grapefruit juice and the response to warfarin. Am J Health Syst Pharm. 1998;55(15):1581-3. 

 

Pou Wee Gan
Pou Wee Gan

M.Pharm, MBBS, BCPS, R.Ph

A pharmacist first, then a medical doctor. An avid tea drinker and an occasional poet.

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