Grapefruit and Medications May Be A Deadly Mix

The number of common prescription drugs that can interact with grapefruit—with potentially serious or even fatal results—is climbing sharply, according to a new comprehensive review published in Canadian Medical Association Journal.

Researchers from Western University report that grapefruit juice can interact with more than 85 oral medications, including certain cholesterol-lowering statins, cancer medications, antibiotics, anti-depressants, pain medications, heart drugs and other widely used pills.

“What I’ve noticed over the last four years is really quite a disturbing trend, and that is the increase in the number of drugs that can produce not only adverse reactions but extraordinarily serious adverse drug reactions,” lead researcher David Bailey, a clinical pharmacologist at the Lawson Health Research Institute, told CBC News.

Between 2008 and 2012, the number of drugs with the potential to cause the most dangerous interactions, including acute kidney or respiratory failure and GI bleeding, has jumped from 17 to 44, says Bailey, “Half of these drugs actually can cause sudden death,” if taken within hours of drinking grapefruit juice (or eating the fruit.)

Although the tart citrus can interact with more than 85 drugs, some interactions are unlikely to cause serious harm. Here’s a closer look at the research and what you need to know to protect your health. A number of other foods, including deli meat, milk and even candy, can also react adversely with certain drugs.

Twenty years ago, the same team of researchers discovered that grapefruit disrupts the body’s metabolism of certain drugs. The tart citrus contains compounds called furanocoumarins that interfere with enzymes that break down the drugs in the gut.

That means more of the drug stays in your body, which could cause it to build up to toxic or even lethal levels. The same compounds are also found in other citrus fruits, including Seville oranges (the kind used in marmalade), limes and pomelos, the study reports, but not in regular oranges.

These adverse reactions can occur many hours after someone consumes grapefruit or its juice—and as little as one glass of grapefruit juice can be enough to trigger dangerous interactions, the researchers report.

 

All of the drugs cited in the review are taken orally and share certain characteristics. They have limited “bioavailability,” meaning that, normally, only small amounts of the drug circulate in the bloodstream. And they all interact in the gut with an enzyme called CYP3A4.

Although this information is included in medication packet inserts, many people, including doctors, aren’t aware of this hazard, the review reported. Drugs with the potential to interact with grapefruit include the following:

  • statins (Zocor, Lipitor)
  • calcium channel blockers (Procardia, Nimotop, Sular)

And certain medications for the following conditions:

  • anxiety (BuSpar)
  • heart arrhythmias (Cordarone)
  • depression (Zoloft)
  • seizures (Tegretol, Carbatrol)
  • malaria (quinine)
  • insomnia (Halcion)

One of the most dangerous medications—if combined with whole grapefruit, concentrate, or fresh juice—is the heart drug Multaq (dronedarone). This interaction can trigger a rare type of ventricular tachycardia, an extremely rapid heart arrhythmia, the researchers report.

Mixing the citrus fruit with the prescription painkiller oxycodone can lead to severe breathing problems, while combining grapefruit and the statin medication Zocor (simvastatin) may spark a potentially life-threatening complication called rhabdomyolysis, in which breakdown of muscle fibers can result in kidney damage of failure.

For a complete list of drugs that react with grapefruit—and which adverse events can occur, click here.

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Dan Mullin is an active writer and editor for the Pluto Daily who covered the 2014 Ebola Outbreak. Mullin attended the Wake Forest School of Medicine before leaving to pursue his lifelong science goal of allowing humans to live forever via a computer/brain transfer.