Newspaper article The Florida Times Union

Unhealthful Mixtures Some Foods Can Be Bad Medicine for Drugs

Newspaper article The Florida Times Union

Unhealthful Mixtures Some Foods Can Be Bad Medicine for Drugs

Article excerpt

Byline: Nicole Johnson McGill, Times-Union staff writer

Most patients know that mixing medications -- prescription as well as over-the-counter -- can be harmful, and sometimes deadly. And most are aware of the dangers of mixing alcohol and medications.

Whether they comply is another story, but the message has been delivered.

Now the medical profession is increasingly sending messages about the potential problems that occur when certain components or nutrients of a food interfere with how the drug is absorbed by the body.

"It's not necessarily an interaction," said Mel Fletcher, a pharmacist at Atkinson's Pharmacies in Mandarin. "It's a competition."

The foods work against the medication, Fletcher said, resulting in too little or too much of a drug entering a patient's system over time.

Some examples:

-- Patients who take Coumadin (Warfarin), an anti-clotting drug that prevents strokes and heart attacks, must avoid green leafy vegetables such as broccoli, spinach, turnip greens and brussels sprouts. The foods contain vitamin K, which produces blood-clotting substances that may reduce the effectiveness of the drug.

-- Synthroid thyroid pills should be taken on an empty stomach. If there's food in the stomach, the drug won't absorb as well. On the other hand, some medications must be taken with food, water or milk.

-- Don't take quinolones with milk, however. Products high in calcium such as milk and yogurt may decrease the drug concentration of the antibiotics.

-- The vitamin C in orange juice has a tendency to increase the absorption of iron. Depending on how much iron a patient needs, that may be either a good thing or a bad thing.

-- Asthma patients using theophylline, a bronchodilator, must avoid meals high in fat because they will increase the amount of drug absorbed. On the other hand, foods high in carbohydrates will decrease the amount of drug absorbed.

Perhaps the food that has received the most attention lately is grapefruit juice. It's cited on numerous drug instruction sheets as something to be avoided because enzymes in the juice can change the metabolism of some medications.

But Florida citrus growers say the dangers are overstated, and they intend to prove it.

"The problem is we've got a lot people saying, 'Don't take grapefruit juice with any drug,' and some are making claims that are not backed up with science," said Andy Laurent, director of research and development for the Citrus Commission.

Laurent cited print advertisements by Merck, the makers of Zocor, a cholesterol-lowering drug, as an example. The ads warn that patients who use the drug should avoid drinking large quantities of grapefruit juice, more than a quart a day.

"How many people drink more than a quart a day? …

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