Drinking grapefruit juice with some medications can be deadly, study warns

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Many people are unaware that grapefruit juice may have adverse reactions when combined with certain medications, and now a new study shows there are even more drugs on the market that carry the risk.

A team of doctors are warning in the Nov. 26 edition of the Canadian Medical Association Journal that between 2008 and 2012, more medications are being sold that can cause serious side effects -- even death -- when combined with grapefruit juice.

"Many of the drugs that interact with grapefruit are highly prescribed and are essential for the treatment of important or common medical conditions," the authors wrote. "Recently, however, a disturbing trend has been seen."

The researchers found between 2008 and 2012, the number of medications with the potential to interact with grapefruit and cause serious problems has increased from 17 to 43 drugs, representing an average rate of increase of more than 6 medications per year.

"This increase is a result of the introduction of new chemical entities and formulations," they wrote.

What's more, there are more than 85 drugs in total that cause some kind of reaction when taken with grapefruit juice, according to the study.

Grapefruits -- as well as Seville oranges used to make marmalade, limes and pomelos (but not typical oranges) -- contain a chemical called furanocoumarins, which affects the way some medications are absorbed and metabolized in the gastrointestinal (GI) tract. As a result, more of the active medication enters the bloodstream. High concentrations of certain drugs can cause kidney damage, GI tract bleeding, respiratory failure, bone-marrow suppression in people with compromised systems and death.

The negative interactions can even occur if grapefruit juice or similar substances are consumed hours before taking the pill, meaning even eating one grapefruit while taking a once-daily medication can have a negative effect. For people who drink grapefruit juice daily, it could magnify the adverse reaction. For example, a statin used to lower cholesterol called simvastatin created a 330 percent higher systemic concentration of the drug when the patient drank a 200-mL glass of grapefruit juice once a day for three days compared to when they just drank water.

"Taking one tablet with a glass of grapefruit juice is like taking 20 tablets with a glass of water," author David Bailey, a clinical pharmacologist at the Lawson Health Research Institute in London, Canada, said to the CBC. He discovered the negative reactions that occur when grapefruit juice is combined with certain medications about two decades ago. "This is unintentional overdosing. So it's not surprising that these levels go from what we call therapeutic to toxic."

Medications that are affected by the citrus juice are all taken orally and combine in the gastrointestinal tract with an enzyme called CYP3A4. Usually only a small fraction of the active drug enters the bloodstream, a process known as very low to intermediate bioavailability.

Drugs that carry an interaction risk include Zocor and Lipitor, which are used to lower cholesterol; Nifediac and Afditab, which lower blood pressure; and some opioid pain relievers like oxycodone. Other medications that can't be combined include some anti-infective, anti-cancer, cardiovascular and urinary tract infection medications.

Patients and doctors can see whether or not the medication has these interaction risks on the package inserts included with the medication, but the study authors fear that no one actually reads them.

"Unless health care professionals are aware of the possibility that the adverse event they are seeing might have an origin in the recent addition of grapefruit to the patient's diet, it is very unlikely that they will investigate it," the authors wrote. "In addition, the patient may not volunteer this information. Thus, we contend that there remains a lack of knowledge about this interaction in the general healthcare community."

People 45 and older are most at risk because they are also the most likely to buy grapefruit juice and also the most likely to take these kind of prescription drugs.

Neal Patel, from the Head of Corporate Communications Royal Pharmaceutical Society, said to the BBC that this study should make people aware of more negative interactions that some food items can have with their medication. For example, milk can stop the absorption of some antibiotics if taken simultaneously.

"Pharmacists are the best port of call for anyone concerned about how their diet may affect their medication," he said. "Information about any interactions would always be included in the patient information leaflet that comes with the medicine."

[summerstormgirl]

Escalitopram, an antidepressant of the 'SSRI' type, also interacts with grapefruit and those taking it should avoid grapefruit juice, or in supplements - I found grapefruit extract in a multivitamin with antioxidants. We should make this more known!

[tom_larson_morgatory]

ALSO, methadone is 1 everyone forgot.There has been alot of deaths because people are gettin whacked.I remember 1 day a while ago I was on methadone 4 pain management,and I bought ruby red grapefruit.I got home and,2 be honest,I thought I took too much methadone,though I knew I couldn't have,and the next day looked it up and viola.METHADONE+GRAPEFRUIT JUICE=DEATH

[tom_larson_morgatory]

ALSO, methadone is 1 everyone forgot.There has been alot of deaths because people are gettin whacked.I remember 1 day a while ago I was on methadone 4 pain management,and I bought ruby red grapefruit.I got home and,2 be honest,I thought I took too much methadone,though I knew I couldn't have,and the next day looked it up and viola.METHADONE+GRAPEFRUIT JUICE=DEATH

[floydj]

Other products contain grapefruit. For example, a local grocery chain sells its own brand of soft drinks - many of which (according to listed ingredients) contain grapefruit juice.

[logicnazi2]

Jaylah54200, Man-made medications used to sustain life is illogical, end of story, nothing callous about it. And if you want to dispute my moral compass, I suggest you do so after investigating that of the person who committed you to a lifetime dependent upon drugs.

[logicnazi2]

So why don't drug manufacturers reduce the effectiveness of the drugs by 20% and doctors tell patients to take their meds with grapefruit juice. This way everyone wins.

Any study that bashes a fruit created by mother nature in lieu of a drug created in a lab by a human doesn't make much sense to me.

[Jaylah54200]

Well, gee, maybe because not everybody likes grapfruit?

And maybe not everybody has a quart of grapefruit juice in their refrigerator at all times?

And maybe there are people who can't afford to buy grapefruit juice all the time?

I mean, if you're going to talk about "logic" (as your name implies), then it seems a lot more logical to me to take medications with water and warn about contraindications (such as grapefruit or other drug combinations) than it does insisting people take their medications with a specific liquid.

I'm sure it never would have occurred to such a callous person as you obviously are, but some of us rely on those drugs for our very lives. Yet, amazingly, I'm in no danger of dying if I don't get my daily 8-ounces of grapefruit juice.

[spyros114]

Another Big Pharma Propaganda

[hypnotoad72]

That's been the case for a long time.

I've had scrips that say "Do not ingest grapefruit" (or drink its juice, whatever) in the past. Do they no longer know how to print little warning stickers? Never mind the 8.5 x 11" paper that tells the warning?

The researchers finding more meds being sold...

What next, all the bought'n'paid-for congresspeople doing a photo-op by drinking big glasses of grapefruit juice? You know, since everybody was so thankful for when they did their big expensive photo-op over gleefully eating "pink slime"?!

Sheesh...

[Larnan5]

Cardizem is also missing from the list.

[AnotherJean]

This article needs grammatical help. "...there's even more" should read "there are even more." The phrase, "bone-marrow suppression in people with compromised systems and death" would indicate that the individuals in question are already dead. It should read "...bone marrow suppression, and death..." It is surprising how often CBS online articles have grammar and spelling errors. They probably don't want to pay to have editors to go over everything. That's unfortunate.

[missssy]

YES, thank you Jean, I noticed that as well. Call me a grammar nazi, but it's really incredible to me that professional journalists don't have a handle on proper English. My grammar and punctuation aren't always perfect, but then I don't write for a living. Why should they have to HIRE an editor - this is grade school stuff - sheez!

[micmac666]

Proof-readers are the first to get cut from the editorial team since they are lowest on the totem pole. Judging from what I read in the press and comments here and elsewhere, grammar, spelling, and punctuation are no longer priorities. I often must read a sentence or paragraph a couple times to understand what the author is trying to convey. It's kind of like reading stoned, I'm told.

[Jaylah54200]

Since CBS didn't bother listing the medications, here they are:

A-C
Alfentanil (oral)
Amiodarone
Apixaban
Atorvastatin
Buspirone
Clopidogrel
Crizotinib
Cyclosporine

D-F
Darifenacin
Dasatinib
Dextromethorphan
Domperidone
Dronedarone
Eplerenone
Erlotinib
Erythromycin
Everolimus
Felodipine
Fentanyl (oral)
Fesoterodine

H-P
Halofantrine
Ketamine (oral)
Latatinib
Lovastatin
Lurasidone
Maraviroc
Nifedipine
Nilotinib
Oxycodone

P-Z
Pazopanib
Pimozide
Primaquine
Quinine
Quetiapine
Quinidine
Rilpivirine
Rivaroxaban
Silodosin
Simvastatin
Sirolimus
Solifenacin
Sunitinib
Tacrolimus
Tamsulosin
Ticagrelor
Triazolam
Vandetanib
Venurafenib
Verapamil
Ziprasidone

[Nate650]

Colchicine is missing from your list.

[Dancing-in-the-Streets]

At one time Carbamazapine or Tegretol, an anti-seizure medication, was on that list - not sure if they took it off or failed to mention it.