Grapefruit (juice, rind etc.. though not so much in the seed extract..) inhibits the cytochrome P450 liver pathway. This means that the drugs that need it to be absorbed, it won't absorb so many. However, there aren't too many of these. Rather, most of the drugs affected are taken up by another process and metabolized OUT of the system via the CYP4A etc.. and other enzymes involved in the pathway.
This means that these drugs actually stay LONGER in the system, which can be dangerous. Remember how all those PDE-5 inhibitor erection drugs like Viagra and Cialis always talked about not taking them with grapefruit juice? Well, that's because the grapefruit would stop the drug from being cleared from the system and thus lead more often to priapism (otherwise known as "The unwanted erection lasting longer than 4 hours!" warned about.
Some Opiates/Opioids are affected as well. Grapefruit makes the effects a little stronger and long lasting, where Rifampin is actually the ultimate P450 Accelerator, which means it basically inhibits absorption and clears the system faster (and a number of other drugs too. Amazingly, I've found that many LLMDs weren't cognizant of this fact!), nullifying the amount that stays in your system.
Artemisia itself is sort of an odd case in that grapefruit helps, according to most literature through a completely different method. Artemeisia is basically a poison that we can tolerate and clear easily, but our bodies do react to it and produce an enzyme in the intestines after a few days of exposure to inhibit uptake. Grapefruit helps prevent this reaction and thus get more of the compound into the body. Still, pulsing is by far the best way, even with grapefruit juice, to ensure as much makes it into your system as possible while being easy on your stomach. Something between 2-3 days on consecutively and the rest of the week off showed the highest absorption, if I recall.
Posted by 365SunnyDays (Member # 29969) on :
Thanks! So helpful.
Posted by chiquita incognita (Member # 30381) on :
Hi Blackstone Can you steer us to your sources of information? Thank you very much, CI
Posted by GiGi (Member # 259) on :
Check Dr. Lai research University of Washington grapefruit juice and artemisinin, etc. cancer, malaria.