Grapefruit inhibits one specific enzyme, one that is found both in the lining of the gut, and in the liver. It is a detoxifying enzyme, designed to protect us from toxins in foods, most likely. But, that enzyme also can act to metabolize drugs.

The effect of inhibiting this enzyme really depends on what drugs you're taking. If you are taking 11 drugs, then chances are that grapefruit is affecting how those drugs work (well, probably one or a few of them).

If you have always been eating grapefruit (or the juice) while taking these drugs, then you have titrated your dosing taking into account the effect of the grapefruit, if you follow.

So, if you've always been a daily consumer of grapefruit, you don't have to change a thing.

If you listed the drugs you take, I could tell you more specifically what your risks are.

Lar