Grapefruit juice prevents enzymes in the walls of the liver and small intestine from metabolizing drugs, thus resulting in a higher concentration of the drug in the bloodstream.
Read this first:
http://www.healingpeople.com/hair transplant/index.p ... Itemid=145
And if you really need to be technical:
GJ = Grapefruit Juice
Time course of GJ-drug Interactions
A research group conducted a study with simvastatin to characterize the duration of the GJ induced CYP 3A4 inhibition. Ten healthy volunteers (9 male, 1 female) received simvastatin 40 mg with either water as a control, and either 0, 1, 3 or 7 days after drinking high-dose GJ (200 mL double-strength GJ) three times daily for 3 days in a non-randomized crossover fashion. As seen with the previous study, significant increases in simvastatin levels after GJ intake were observed on the day 0 study when compared with water. Simvastatin AUC was increased 1250%, with Cmax increased 1104%. Time to peak concentration (Tmax) was also prolonged from 2 hours to 4 hours (100% increase). This effect was significantly reduced if 24 hours elapsed between the last GJ intake and simvastatin dosing. At this time, simvastatin AUC was increased 105%, and Cmax was increased 136%. The authors noted that the effect of even high-dose GJ 24 hours after ingestion is only about 10% of that seen with concurrent GJ and simvastatin intake. AUC and Cmax of simvastatin when taken on day 3 and day 7 after last GJ intake were not significantly elevated compared to control, indicating that the interaction potential of even high amounts of GJ intake dissipates within 3-7 days after last GJ ingestion.
This is useful for characterizing the time course of GJ-drug interactions, and fits with prior expectations that the GJ effect can last up to 3 days after last GJ ingestion.90
