why does grapefruit juice potentials the effects of some medications while decrease the absorption of others?

Question

ie. grapefruit juice or extract amplifies the effects of some sleep meds (Dayvigo) while decreases the effects of others (Vyvanse)

In: Chemistry

Answer 1

Grapefruit binds together with the liver chemical (CYP3A4) that digests many medications. If the liver chemical doesn’t digest the drug (ie because you had grapefruit), your intestines absorb MORE of it because there’s more ‘available’.
Grapefruit interacts with some other medications making them LESS effective, by blocking some of the body’s ’drug transporters’. This is a pretty new find, so less is known about the details of this.
😬
Source: I’m an Ambulatory Medicine Specialty Certified Registered Nurse and I’m on the internet because I’m supposed to be getting some continuing education credits to renew my specialty certification, but I took ‘just a quick look’ at Reddit 🤭😆