Not all grapefruit juice is the same for the purpose of Sirolimus enchancment

Why keep on promoting something that is much more dangerous than grapefruit juice?
“Ketoconazole may cause liver damage, sometimes serious enough to require liver transplantation or to cause death. Liver damage may occur in people who do not already have liver disease or any other conditions that increase the risk that they will develop liver damage.”
Ketoconazole: MedlinePlus Drug Information.


I pointed out previously that grapefruits being a natural product, they will vary in their content of these natural products by variety, season, and weather.

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This is notable. AFAIK, grapefruit inhibits CYP3A4 but is not known to inhibit P-glycoprotein. And:

Sirolimus is known to be a substrate for both cytochrome P-450 3A4 (CYP3A4) and p-glycoprotein (P-gp). Inducers of CYP3A4 and P-gp may decrease sirolimus concentrations whereas inhibitors of CYP3A4 and P-gp may increase sirolimus concentrations.

AFINITOR® (everolimus)
CYP3A4 and/or PgP inhibitors: Avoid the use of strong CYP3A4 inhibitors. If patients require co-administration of a moderate CYP3A4/PgP inhibitor, reduce the AFINITOR dose to 2.5 mg daily. An AFINITOR dose increase from 2.5 mg to 5 mg may be considered based on patient tolerance. Resume dose administered prior to inhibitor initiation, once the inhibitor is discontinued for 3 days
Dosing & Administration - AFINITOR® for Renal Angiomyolipoma

So quercetin would be expected to have a dual mechanism of increasing cellular levels of rapalog, both by inhibiting degradation by CYP3A4 and inhibiting efflux by P-gP.