Okay, this is going to be a very ignorant response, so be warned, lol. I have heard that grapefruit can cause liver enzymes to accelerate absorption of medication and enhance it's effects. I know a lot of pill heads recommend drinking grapejuice with their opiates for this reason cause you get a stronger effect and I've been told to avoid using it while I am on Cymbalta cause it can do similar things. I've heard it can have an impact on hrt as well, but I avoid it because I am on cymbalta so never went to far into it. Like I said, take all of this with a grain of salt, but I do know that it can interact with liver enzymes and it can have some impact with certain medications.