OGDEN -- Before you reach for a glass of grapefruit juice to jump-start your morning, take a look at your medication list.
A recent study found the potency of more than 80 drugs -- including antidepressants, antibiotics, birth control pills, and heart and blood pressure medications -- increases when combined with any form of grapefruit.
The study, "Grapefruit-Medication Interactions: Forbidden Fruit or Avoidable Consequences?" published in March in the Canadian Medical Association Journal, also found many of those drugs can cause severe and sometimes deadly side effects when mixed with the fruit.
"Grapefruit juice inhibits enzymes in the intestines responsible for the metabolism of certain drugs before they enter the bloodstream," said Dustin Waters, infection disease clinical pharmacist at McKay-Dee Hospital in Ogden.
Grapefruit contains an active ingredient called furanocoumarins, which irreversibly blocks the drug-metabolizing enzyme, causing many different side effects and an overdose hazard.
For example, when taking the cholesterol-lowering drug Zocor with a glass of grapefruit juice once a day for three days, the drug increases in the bloodstream by 330 percent, researchers found.
"Ingestion of as little as 1 cup, or 8 ounces, of grapefruit juice or one whole grapefruit has been shown to produce significant drug interactions," they wrote.
Some of those medications, Waters said, cause increased risk of bleeding, heart rhythm disturbances, dizziness, breathing problems, muscle breakdown, low blood pressure and hallucinations.
The study also found some of the drugs, when mixed with grapefruit, can cause acute kidney failure, respiratory failure and sudden death.
"What I've noticed over the last four years is really quite a disturbing trend," said David Bailey, a clinical pharmacologist at the Lawson Health Research Institute in Canada and one of the authors of the study. "Taking one tablet of some medications with a glass of grapefruit juice can be like taking 20 tablets."
The study's authors also said people over the age of 45 buy the most grapefruit and also take the most prescription drugs, making them more likely to suffer interactions.
Waters said patients should always check with their pharmacist and doctor to see if their medications interact with grapefruit.
Medications that interact with grapefruit
These are among the more than 80 medications that cause dangerous side effects when taken with grapefruit.
* Amiodarone (Cordarone(r)): heart rhythm disturbances
* Dronedarone (Multaq(r)): heart rhythm disturbances
* Atorvastatin (Lipitor(r)): increased risk of muscle breakdown
* Lovastatin (Mevacor(r)): increased risk of muscle breakdown
* Simvastatin (Zocor(r)): increased risk of muscle breakdown
* Nifedipine (Procardia(r), Procardia XL(r), multiple others): low blood pressure
* Rivaroxaban (Xarelto(r)): increased risk of bleeding
* Ticagrelor (Brilinta(r)): increased risk of bleeding
* Erythromycin (Ery-Tab(r)): heart rhythm disturbances
* Clopidogrel (Plavix(r)): decreased effectiveness
* Buspirone (Buspar(r)): dizziness, drowsiness
* Dextromethorphan (Robitussin DM(r), Delsym(r), numerous over-the-counter cough and cold preparations): hallucinations, drowsiness
* Oxycodone (Oxycontin(r), Percolone(r)): trouble breathing, drowsiness
* Quetiapine (Seroquel(r)): dizziness, drowsiness
Source: Canadian Medical Association Journal