Tuesday Morning News: Stop Consuming Grapefruit While Taking Drugs, for One


Pile of leaves was a huge disappointment. "Good for them"
I hate grapefruit juice. This is further proof that it's evil.
Interesting about the drugs that interact with grapefruit juice. I am taking two of them.

For those who don't know, tadalafil which is on the list, is available under the brand name Cialis. At 62 taking a boner pill may not be critically necessary but it greatly improves the quality of my sex life.
Cheetah was pretty badass. Though I can't be the only one who was hoping it would culminate in her catching up to whoever the cruel bastard was pulling the string and maul them.
Can't the Democrats in the senate pass a bill extending middle class tax cuts and passing it on to the house without Republicans? Then the ball is in the Republican house. If they refuse to pass it, the "fiscal cliff" is on them. They lost the election. If they want to make things worse for themselves, let them.
That's interesting. Every time I've taken a multivitamin after eating half a grapefruit with my breakfast, I've puked it up. #themoreyouknow
They banned my favorite antihistamine after some idiot failed to read the "DO NOT TAKE WITH GRAPEFRUIT JUICE" warning on the box, and died. No other antihistamine works as well as that one did. I wish they'd banned grapefruit juice instead of my beloved terfenadine.
Further evidence for my hypothesis that grapefruit is poison.
@7, good news! Terfenadine itself was not the magical chemical that ...antihistaminized you. That drug is almost entirely converted by the body in short order to fexofenadine before it hits the circulation (unless inhibitors of that reaction, like grapefruit chemicals, are present, in which case terfenadine in the blood causes cardiotoxic effects).

Hmmm, fexofenadine—that would be Allegra, legally clearing airways since 1996.

Happy breathing!
I see grapefruit is not the only suspect juice.

"The problem is caused by an active ingredient in some citrus fruits, including grapefruit, limes and pomelos. Even the Seville oranges used in marmalades can trigger it. The fruits produce organic chemical compounds called furanocoumarins, which interfere with a human digestive enzyme."

I don't buy grapefruit nor grapefruit juice. But I was served some a short while back. I attended a party where a punch made of grapefruit juice, ice cream, and sparkling water was served.
I like how we see grapefruit as the danger, and not the prescription drugs.
It's not just grapefruit. Seville oranges have the same stuff in them.

For the record, what actually happens with the interaction is that the grapefruit (seville orange, etc.) competes for a metabolic pathway in the liver that the drug needs to use to be metabolized. This increases the half-life of the drug in the body, often significantly. If you consume grapefruit (or the drug) only infrequently, it's not as much of a problem as if you have it every day. What happens with frequent consumption of grapefruit is that the pathway remains blocked and the drug can quickly build up in the bloodstream to toxic levels if you're taking periodic doses of it.

This only happens with drugs that use that one particular enzymatic pathway (Cytochrome P450/CYP3A4) in the liver. Unfortunately, there are quite a few that do.

Unless you read the professional package insert for each drug you're prescribed to make sure it's not using that pathway to be metabolized, yeah, avoid grapefruit. (And Seville oranges, and pomelos.)
Drug interactions, along with side effects from other dietary supplements, regulated or unregulated, is really hard to program for.

I remember when we were designing the Group Health software. Most medical insurance pharmacies only went out to two or three interactions, extending it as far as we did was a major pain.

Here's a hint: If it says "take on an empty stomach" that means nothing in it, other than water.
@11 - Drugs are awesome. Grapefruit is the devil's own gallbladder.
Is the grapefruit thing why people always say that drinking OJ or grapefruit-J will enhance your LDS/mushroom experience?
enhance your LDS/mushroom experience

Mormons do magic mushrooms? Who knew?

(Yes, I understand that it was a typo.)
I only take my Mormons with mushrooms.
Sorry. Psilocybin is metabolized by 2D6. Like meth and ecstacy.
@14 No, they're not. Not the crap produced by the pharma industry. This is just nature's way of telling us that we shouldn't poison our bodies w/ expensive & damaging chemicals.

@19 - Oh, for a second there, I thought you were going to defend grapefruit, the devil's own gallbladder (from now on, to be referred to in full). Yeah, I can agree with you to a certain extent, but I warn you, my listening things and thinking stuff shuts down when I hear "pharma industry" and "chemicals".
That cockroach thing was very disturbing. I guess, 'thank God' the camera was off when (a few minutes later??) he died. New word for me, signs of anaphylaxis on the skin are called "stigmata." Sad story. Gross. And sad.
Goddammit. I love grapefruit juice. Once I read somewhere on the Internet that it slows down metabolism of caffeine so drinking it alongside a morning cup of joe would make the effects of caffeine last longer. My husband remembered it the other way around. We got into an argument about it at a party in front of a research chemist who set us straight, but now I can't remember which of us he said was right. I thought my husband was vindicated, but this report leads me to believe I was on to something.
@22 It sounds like you were right, since it just seems to go one way with grapefruit: make the drugs last longer and even build up in concentration.
Cancer Causes Control. 2009 Aug;20(6):803-9.

Prospective study of the association between grapefruit intake and risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC).

TLDR: No connection between grapefruit, birth control, and breast cancer found.

Grapefruit inhibits cytochrome P450 3A4 and may affect estrogen metabolism. In the European Prospective Investigation into Cancer and Nutrition (EPIC), we examined the relationships of grapefruit intake with risk of breast cancer and with serum sex hormone levels. 114,504 women with information on dietary intake of grapefruit and on reproductive and lifestyle risk factors were followed for a median 9.5 years and 3,747 incident breast cancers were identified. Fifty-nine percent of women reported eating grapefruit, 4% ate > or = 60 g/day. Cox proportional hazard models were used to estimate the hazard ratio (HR) for breast cancer according to grapefruit intake, adjusting for study centre, reproductive factors, body mass index, energy intake, and alcohol intake. Grapefruit intake was not related to the risk of breast cancer: compared with women who ate no grapefruit, women with the highest intake of > or =60 g/day had a HR of 0.93 (95% CI 0.77-1.13), p for linear trend = 0.5. There was no relationship between grapefruit intake and breast cancer risk among premenopausal women, all postmenopausal women, or postmenopausal women categorized by hormone replacement therapy use (all p>0.05). There was no association between grapefruit intake and estradiol or estrone among postmenopausal women. In this study, we found no evidence of an association between grapefruit intake and risk of breast cancer.
Gosh darn it. No more dropping hits of Mormon for me. Sigh.