I happened on an article about Grapefruits and was surprised how dangerous they can be, beside tripping over one or someone dropping one from a 20 story building. It's the only food that interacts with your medications, except Lime and a couple other juices so bitter there's not much chance you'll will consume enough to be a problem. But Grapefruit is another story, older people generally take more kinds of meds and Grapefruit zings tired taste buds.
The human body has mechanisms to break down stuff in the stomach. The one involved here is cytochrome P450, a group of enzymes converting various substances to inactive forms. Drugmakers factor this into their dosage formulation as they try to figure out what’s called the bioavailability of a drug, how much of a drug gets to your bloodstream after enzymes in your stomach. For most drugs, it is surprisingly little, sometimes only 10%.
Grapefruit juice kills the P450s so for about 12 hours so you get 100% of the drug in your system instead of the ?% the drug company figured.
For some drugs that can be serious overdose.
The drugs affected by grapefruit juice are...
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.
If you think it may affect you
read the short article.