[jeremygaither]

For many people taking a range of medications, especially mental-related medications, eating grapefruit can cause a large range of negative side effects. Several medications will become inert in the presence of citric acid and vitamin C. Oranges, if eaten at the appropriate times during their medication regimen (usually an hour after or before medication), is usually safe. Fiber is also important, but it can also absorb medications and render them inert if taken at the wrong times. Fiber is usually safe two hours before or after medication, which can be difficult to orchestrate, depending on medication regimens.

[_Microft]

This topic has its own Wikipedia entry:

https://en.wikipedia.org/wiki/Grapefruit%E2%80%93drug_intera...

[lioeters]

Thank you for the warning. Fortunately I'm not taking any medications these days, but in case I do in the future, I'll keep in mind the interaction with grapefruits.

> 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.

> In some of these cases, the grapefruit interaction is not a big deal, because they’re safe drugs and even having several times the normal dosage is not particularly dangerous. In other cases, it’s exceedingly dangerous.

https://www.atlasobscura.com/articles/grapefruit-history-and...

[hirvi74]

This is the first I have ever read about fiber causing issues with medications.

What effects does fiber have on certain medications and why? Does it slow the absorption rate due to the medication being dispersed in the fiber?

[eurasiantiger]

It’s not the fiber. Grapefruit contains furanocoumarins which inhibit the action of the liver enzyme CYP3A4. That particular enzyme breaks down most medications.

[bawolff]

Wouldn't that be the Furanocoumarin not the vitamin c?