What kind of side effects from grapefruit and buspirone? I am a regular drinkrr of grapefruit juice?

In simple terms, if you take grapefruit juice (enough of it on an empty stomach before taking Buspirone - white grapefruit juice made from concentrate seems to cause this effect more) it will slow down the metabolism of the drug in your liver, because grapefruit inhibits some of the liver enzymes needed for the drug to work. What kind of effects might that cause? It´s hard to say and really depends on the individual and the drug. I would guess, the drugs onset and half-life duration would be affected. it may be less or more effective, depending on your prospective. Certain effects of the drug (desirable and undesirable) may be pronounced and intense.

The source of the answer is Wikipedia and medically cited references:

Interactions

Buspirone has been shown in vitro to be metabolized by CYP3A4. This finding is consistent with the in vivo interactions observed between buspirone and these inhibitors inducers of cytochrome P450 3A4 (CYP3A4), among others:

Itraconazole: Increased plasma level of buspirone
Rifampicin: Decreased plasma levels of buspirone
Nefazodone: Increased plasma levels of buspirone
Haloperidol: Increased plasma levels of haloperidol
Carbamazepine: Decreased plasma levels of buspirone
Commercial grapefruit juice: contains rind, the source of the competing compound: Significantly increases the plasma levels of buspirone

** The likely mechanism of the interaction caused by grapefruit juice is delayed gastric emptying or inhibition by a substance in grapefruit rind of cytochrome P450 3A4-mediated first-pass metabolism of buspirone. **