adhd and grapefruit

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Grapefruit can change the way your ADHD meds work:

https://www.atlasobscura.com/articles/g ... teractions

[ . . . ]

None of this is a mystery, at this point, and it’s shockingly common. Here’s a brief and incomplete list of some of the medications that research indicates get screwed up by grapefruit:

Benzodiazepines (Xanax, Klonopin, and Valium)
Amphetamines (Adderall and Ritalin)
Anti-anxiety SSRIs (Zoloft and Paxil)
Cholesterol-lowering statins (Lipitor and Crestor)
Erectile-dysfunction drugs (Cialis and Viagra)
Various over-the-counter meds (Tylenol, Allegra, and Prilosec)
And about a hundred others.

[ . . . ]

The reason why grapefruit is singled out is for back when the grapefruit diet was popular (I don't remember exactly when, but my sister tried it). A lot of people found their medications weren't working.

In the early 2000s I took Tegretol (carbamazepine) and that had a grapefruit warning in the paperwork it came with.

Wonder what's in grapefruit that does all that? If it's fruit in general, that's bad news for people who think they need any of those meds. Fruit is kind of good for people, though I find it too messy and / or acidic apart from good grapes and cherry tomatoes plus a bit of vitamin C powder mixed with my taters. I don't use any of those meds though so it's no help to me personally.

I'm on Lamictal to help with meltdowns along with headaches, I don't think it has a Grapefruit warning on it. I like Grapefruit juice now and then, but it gives me heartburn.

https://en.wikipedia.org/wiki/Grapefrui ... teractions

The effect was first discovered accidentally in 1989, when a test of drug interactions with alcohol used grapefruit juice to hide the taste of the ethanol. A 2005 medical review advised patients to avoid all citrus juices until further research clarifies the risks. It was reported in 2008 that similar effects had been observed with apple juice.



The effects are caused by furanocoumarins (and, to a lesser extent, flavonoids). These chemicals inhibit key drug metabolizing enzymes, such as cytochrome P450 3A4 (CYP3A4). CYP3A4 is a metabolizing enzyme for almost 50% of drugs, and is found in the liver and small intestinal epithelial cells. As a result, many drugs are affected. Inhibition of enzymes can have two different effects, depending on whether the drug is either

metabolized by the enzyme to an inactive metabolite, or
activated by the enzyme to an active metabolite.

In the first instance, inhibition of drug-metabolizing enzymes results in elevated concentrations of an active drug in the body, which may cause adverse effects. Conversely, if the medication is a prodrug, it needs to be metabolised to be converted to the active drug. Compromising its metabolism lowers concentrations of the active drug, reducing its therapeutic effect, and risking therapeutic failure.

Low drug concentrations can also be caused when the fruit suppresses drug absorption from the intestine.

Grapefruit can block one mechanism and the result is you overdose. It can also block another and the result is you get less med than you think you will get. The original article I linked above has some more details. The Wikipedia article funeralxempire linked has some others. Something related to a chemical in the grapefruit which the grapefruit fruit developed to fight fungus. Some apple juice may do the same thing. Other citrus fruits too.

My son asked me about Grapefruit and if it is a combination or crossbreed/hybrid of two other fruit. I said I thought it had something to do with grafting. The answer is complicated - and really “both hybrid and grafting”.

But that is perhaps another thread.

The thing to know is that most citrus you can buy is probably a close genetic cousin to grapefruit (and all the other citrus on the market) and so biologically and chemically “might be similar”.

Talk to your doc if you want to know about a specific med you take. And google a lot.