Question:

Hi, I am taking Triameterene, Atacand, and Zoloft and I was wondering if either eating the fruit or drinking the juice would affect these?

Thank you very much!

Answer:

Information regarding potential drug interactions between pomegranate juice and medicines is sparse and inconclusive.  Pomegranate juice, like grapefruit juice, inhibits CYP3A4 enzyme activity in the walls of the intestines.  Recently pomegranate juice has also been found to inhibit another enzyme in the intestinal wall called CYP2C19.  Blocking the action of these enzymes may allow more of the medicines usually broken down by the enzymes to enter the blood stream.  Of the medicines mentioned, only sertraline (Zoloft) is a substrate for CYP3A4.  However, sertraline is metabolized by multiple enzymes, so inhibiting CYP3A4 may have no noticeable effect on blood levels of sertraline or how a particular patient responds to this medicine.  None of the medicines mentioned are broken down by CYP2C19.

Both triamterene and candesartan are used to treat high blood pressure.  Pomegranate juice can reduce blood pressure further by a similar mechanism to candesartan.  Medicines used to treat high blood pressure often cause dizziness, especially when standing up from a sitting or reclining position.  Since pomegranate juice can cause an additional reduction in blood, drinking it could increase the likelihood of this happening.  Additionally, triamterene, candesartan and pomegranate juice can reduce potassium excretion, leading to excess potassium in the body.  Symptoms of excess potassium include muscle weakness, slow or abnormal heart beats, abdominal pain, and diarrhea.

With our current level of knowledge, it’s unclear whether the actions of pomegranate juice in combination with the listed medicines will result in a significant change in the activity of these drugs. At this point there does not seem to be any contraindication to regular use of pomegranate juice with these medicines.  Based on the current list of medicines, a slight reduction in blood pressure is possible.   If other medicines are needed in the future, it will be important to consider the potential drug interactions in light of additional knowledge as it becomes available.

When considering potential interactions between foods, herbal products and other dietary supplements, it is important to realize that batch to batch differences in activity of the supplements may change the likelihood of a drug interaction occurring, even if there is no change in the prescription medicines one is taking.  Always make sure your doctor and the pharmacists who fill your prescriptions know about all of the dietary supplements that you are taking.

This response was prepared in part by Bethany Loader, PharmD Candidate at the NetWellness.org, College of Pharmacy.  

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