Thursday, December 20, 2012

Grapefruit And Drugs Don't Mix

And as more drugs emerge from the pharmaceutical pipeline, the list of drugs that interact with grapefruit (and Pomelos and Seville oranges - a bitter orange from Asia used to make marmalade, so marmalade too) is growing.

Eating grapefruit can lead to higher doses of a drug in the bloodstream. This recent article from the New York Times describes one mechanism:
"Under normal circumstances, the drugs are metabolized in the gastrointestinal tract, and relatively little is absorbed, because an enzyme in the gut called CYP3A4 deactivates them. But grapefruit contains natural chemicals called furanocoumarins, that inhibit the enzyme, and without it the gut absorbs much more of a drug and blood levels rise dramatically."
Those higher doses can be deadly. The article describes...
"The 42-year-old was barely responding when her husband brought her to the emergency room. Her heart rate was slowing, and her blood pressure was falling. Doctors had to insert a breathing tube, and then a pacemaker, to revive her.

They were mystified: The patient’s husband said she suffered from migraines and was taking a blood pressure drug called verapamil to help prevent the headaches. But blood tests showed she had an alarming amount of the drug in her system, five times the safe level.

“The culprit was grapefruit juice,” said Dr. Unni Pillai."
Lots of drugs interact with grapefruit - benzodiazepines (Valium, Xanax), antidepressants (Zoloft), statins (Lipitor, Zocor), erectile dysfunction drugs (Viagra), antihistamines (Allegra), painkillers (oxycodone, hydrocodone, Tylenol). Wikipedia has a lengthier list.

This is something I learned years ago in one of my nutrition classes, but my peers and I weren't taking many drugs so it sat on my mental periphery. Not anymore.
Thanks, BL!


Bix said...

I love that photo of grapefruit.

Unknown said...

This is true of pomegranate too but for some reason in isn't as widely addressed.

Bix said...

Pomegranate too? That's good to know.

Angela and Melinda said...

A lot of scrips come w/ warning labels about grapefruit--I used to see them when I was caring for my parents.

Bix said...

Speaking of parents ... I think grapefruit juice has gone out of favor over the years. There are certainly a lot more choices. I mean, pomegranate juice wasn't even heard of, well, not to us scratchy folk. (Reading around, there does seem to be some interaction, as Diana said).

Another juice I don't see much anymore is prune juice. I remember helping patients fill out their menus when I was a Red Cross Student Volunteer (like a candy striper except we wore blue striped pinafores instead of pink and could do more medical tasks) and beverages were ... orange juice, grapefruit juice, and prune juice. Prune juice was quite popular!