Recently, scientists at Chicago Medical University found that eight ounces of grapefruit juice a day can slow the body’s metabolism of sirolimus. Data from a clinical trial study published in the August issue of Clinical Cancer Research showed that cancer patients can achieve similar benefits from taking anti-cancer drugs by drinking a glass of grapefruit juice a day. Grapefruit juice may also help patients avoid the side effects associated with taking high doses of the drug, while also reducing medication costs. They observed a 350% increase in sirolimus metabolism levels in patients who drank eight ounces of grapefruit juice, and a 500% increase in sirolimus metabolism levels in patients who took ketoconazole, a drug that slows metabolism, daily. Grapefruit juice inhibits the enzymes in the intestine which break the absorption of sirolimus and some other drugs. This effect is only within a few hours of using grapefruit juice to begin with, and the researchers note that the effects of grapefruit juice slowly wear off day by day. Grapefruit juice and drugs with similar mechanisms can significantly increase blood levels of many drugs, but overdose has long been considered harmful; instead, this latest study found that grapefruit juice can increase the availability and effectiveness of sirolimus by some means.