Warning! Apparently you’re not supposed to chase your allergy medication, most infamously the drug Allegra, with orange juice. Even more, grapefruit juice could prove to be lethal when taken with some medication.
I’m sorry, when did this happen? Does this mean that for the past 10 to 15 years I’ve been nullifying all of my medication by pairing it with a glass of freshly sqozen orange juice? (That’s right, I said sqozen; “The ice is ready to freeze, the ice is frozen / The oranges are ripe and have been sqozen”) (Didn’t think you were going to learn English today, did you?)
The scoop: According to a New York Times report in 2008, grapefruit juice lessened the absorption of fexofenadine (Allegra), and can produce a toxic effect when used with almost 50 other medications including popular names such as Zoloft (anti-depressant), Viagra (another anti-depressant *wink wink*), Valium (anti-anxiety), Lipitor (for lowering cholesterol), Aleve and Midol (Naproxen-containing pain relief and anti-inflammatory (analgesic) drugs). Grapefruit, orange, and apple juices were also found to decrease absorption of etoposide (an anticancer drug), some beta blockers (for high blood pressure), cyclosporine (to prevent organ rejection), and some antibiotics.
Drinking citrus juices and/or eating the entire fruit should be avoided while taking these medications and others because “chemicals in these fruits interfere with the specific enzymes that break down (metabolize) the medications. This can lead to much higher blood levels of these medications and can cause serious side effects.” Let’s find out more, shall we?
Cause/Mechanism of action:
The chemicals in grapefruits and its relatives are furanocoumarins that “affect the cytochrome p450 (CYP) system (especially at isoenzyme CYP3A4) by binding to the isoenzyme as a substrate and impairing” the first important step in the metabolic break down of medication in the small intestine and/or the liver “by direct inactivation or inhibition of the enzyme…The net effect on the CYP enzymes from this inhibition seems to be a selective down-regulation of CYP3A4 in the small intestine. For certain drugs which are known to be CYP 3A4 metabolized, less [of the] drug is metabolized prior to absorption, and greater amounts of these drugs reach the systemic circulation.” The resulting high blood concentration of circulating medication has toxic consequences, e.g. cardiac arrest and death. However, if the drug has a high “oral bioavailabilty,” i.e. most of it is released before it reaches the small intestine (located right after the stomach), then it will not be affected by citrus juices in the same way. In other words, grapefruit juice only affects drugs that first need to be metabolized by the small intestine/liver before becoming active, which explains why citrus juices affect some medications and not others. Also important to note is that the effects of grapefruit on this family of enzymes lasts up to 72 hours, meaning that within that time it is still not safe to eat/drink anything grapefruit-related (e.g. seville oranges, pomelos, sweeties, melogold grapefruits, limes, star fruit, pomegranates, pawpaws).
There is an easy way to avoid this: Take all of your medication with WATER.
Drug/Food interactions, as I’ve discovered, are numerous and difficult to keep track of—and if the internet accounts are true, these effects are not well-known (if at all) by physicians, yet much better known by pharmacologists (understandably, because they are knowledgeable and trained in drug physiology (“pharmacokinetics”) and interaction) (hopefully). To list a few notable and most likely commonly abused drug/food mistakes:
- Theophylline, an asthma medication containing a member of the xanthine family whose molecules resemble caffeine and are found in coffee, tea, cocoa beans (chocolate), should not be consumed with large servings of these same foods
- Heparin, Warfarin and Coumadin, blood clot preventing (anticoagulant) medications, should not be taken when eating a heaping helping of broccoli, spinach, or leafy green vegetables because of their high concentrations of vitamin K that promotes the formation of blood clots (the opposite of what the medication is trying to do) and should not be consumed with garlic, also an anticoagulant and also commonly adds spice to leafy green vegetables
- Fiber, soluble and insoluble, negatively affects drug absorption such as that of acetaminophen (i.e. Tylenol). Thus, this medication should not be taken with the likes of pectin containing fruits e.g. apples, oranges, grapefruits (sound familiar…) or bran
- No orange juice with antacids due to the juice apparently increasing the absorption of the aluminum from the antacid
- Wait to drink tea until a couple hours after taking iron supplements (or your multi-vitamin for that matter); tea contains tannates that halt iron absorption, instead take these aids with acidic juices like orange juice (Are you keeping up??)
- Etc. etc. etc. Just drink water people.
Just to recap: a) Be aware of the medication(s) you are taking to make sure they don’t have any dietary no-no’s; b) Ask a pharmacist (or a smart doctor) about any fruits, herbs or veggies that shouldn’t be eaten with your medication(s); c) Go online like I did and look up your medication(s), and perhaps you’ll find out more information that you wanted to know…like I did…
P.S. Here are some common/popular medications that don’t have a reaction to grapefruit and the like: Xanax, Prevacid, Quinine, Coumadin (don’t take that one with leafy green veggies though! Do you remember that from like 5 minutes ago?)
To find out more about the effects of juices on medications: NYTimes.com, EverydayHealth.com, HolisticOnline.com, Wikipedia (Theophylline, Anticoagulant, Furanocoumarin, Grapefruit-Drug Interactions Website
