Q: I’ve read that grapefruit juice should not be used when taking medicine and food supplements. Later I read that this applies to orange juice also. My husband said I’m wrong. What’s the truth? Should I worry about V8, tomato juice, beer, wine, other alcohol, or even soda? Please clear up this small family feud and sign me a ‘worry wart’.
A: Grapefruit and other citrus drinks may interfere with some medications (85 in all) prescribed by a physician. The problem is that chemicals in the fruit juice may interfere with the enzymes that metabolize the medication in the digestive system and the way in which it processed by the liver. This translates to the drug remaining in your system for too short or too long a period of time. The medication that breaks down too quickly simply doesn’t have sufficient time to work. Those that remain too long can increase to dangerous levels and cause unwanted side effects.
It would be impossible for me to list all the drugs that can interfere with citrus, but antibiotics for infection, cardiac medications, those taken for high blood pressure, and others taken to lower cholesterol levels are worthy of note. This does not imply if you are on any drugs for these disorders that you can drink your grapefruit juice, take your medication later, or reverse the process and take the medication with water or another drink and follow-up an hour or so later with that beloved grapefruit juice. The product may actually have to be removed from your diet.
For example, statin drugs are prescribed for individuals with high cholesterol levels, or for those with cardiovascular disorders. According to the American Journal of Clinical Nutrition, furanocoumarins, organic chemical compounds in many plants including grapefruit, inhibit the efficacy of an important enzyme that helps the body process the medications we take and balances out how much of it goes into the bloodstream. Because of the furanocoumarins hindering this enzyme, larger amounts remain in the blood and could increase a person’s risk for muscle breakdown, liver damage and kidney failure. Because statins interact differently, you should check with your physician to determine if the one you are taking falls into the ‘no grapefruit’ category. And remember also that this only applies to oral tablets. Injectable drugs and skin patches may be okay.
Grapefruit is also known to interact with drugs used to treat nausea, urinary tract infections, cancer medications, anti-anxiety drugs, and immunosuppresants. The FDA has stated grapefruit might also affect the body adversely if a person is on an antihistamine such as Allegra.
On to orange and other juices. Many medications can interact with orange, apple and cranberry juices. As an example, the drug fact label of over the counter fexofenadine (Allegra) indicates the product should not be consumed with fruit juices. Period. Seville oranges, limes and pomelos can produce drug interactions similar to grapefruit by inhibiting intestinal CYP-34A. Orange, apple and some other juices appear to inhibit OATPs (organic anion-transporting polypeptides) that aid in the absorption of drugs. The OATP inhibition results in reduced absorption and potentially decreased serum levels of drugs transported by OATP. Cranberry juice can have a bearing on warfarin, an anticoagulant. According to some researchers, reduced warfarin metabolism results. Further, it causes an increased bleeding risk.
So, I guess you win this round. Without knowing which medications you are on, I cannot recommend you take or eliminate citrus drinks. That answer is best left to your prescribing physician(s). Good luck.
