How does GJ cause drug interactions with medications ?
OK, this is the short answer. Chemical compounds in GJ (primarily the compound 6’7′-dihrdroxybergamottin) are known to inhibit an enzyme system found in the small intestine that metabolizes some drugs prior to absorption into the bloodstream. This system is called CYP 3A4 and does play a role in the metabolism of certain drugs. Drugs that are affected by this interaction are metabolized less than usual when they are taken with GJ, allowing a higher amount to reach the bloodstream, and this will cause higher drug levels, sometimes with increases in clinical effects or side effects. GJ also affects a transporter called p-glycoprotein. The effects of this are less clearly defined, but p-glycoprotein is responsible for actively secreting some absorbed drugs back into the small bowel. For more detail, see the mechanism of action page.
