December 03, 2006

Food and Drug Interactions

Last month, an antioxidant found in red wine was found to increase metabolic rates in humans and mice. Resveratrol has an implicated role in aging as it has been shown to extend the lifespan of rats (scroll to the very bottom), but Abel PharmBoy cautions us not to take these preliminary results too far. Wine also has tannins (procyanidins) that have a protective effect against heart attacks by suppressing the synthesis of a potent vasoconstrictor, endothelin-1.

Time to celebrate! What a great excuse for the upcoming Christmas holidays. ;)

If you're also celebrating with some red wine because of a miracle MAO inhibitor drug that has given you your life back after severe depression--

My Pharmacology textbook by Golan told the tale of a young woman, Phyllis, who was prescribed a new drug to treat her depression. She recovered and went to a wine and cheese gala event to enjoy her favorite chianti with some fava beans. *cue disturbing Hannibal Lector slurping*

A short while later, Phyllis had a throbbing headache in the occipital region (back of her head) and recalling her doctor's instructions, she went to the ER. It was a good thing too... she had an alarmingly high blood pressure and she could have died. A new side effect profile was later proven linking tyramine-rich foods with MAO inhibitors. Tyramine resembles other neurotransmitters in her body and an excess release of these catecholamines kicked her body into high gear.

The following tyramine-rich foods are contraindicated with MAO inhibitors, according to the FDA:

Alcohol: Do not drink beer, red wine, other alcoholic beverages, non-alcoholic and reduced alcohol-beer and red-wine products.
American processed, cheddar, blue, brie, mozzarella and Parmesan cheese; yogurt, sour cream.
Beef or chicken liver; cured meats such as sausage and salami; game meat; caviar; dried fish.
Avocados, bananas, yeast extracts, raisins, sauerkraut, soy sauce, miso soup.
Broad (fava) beans, ginseng, caffeine-containing products (colas, chocolate, coffee and tea).

In a show of responsibility, cites that St. John's Wort can be used for mild depression by minor MAO inhibiting action and therefore, tyramine-rich foods should be avoided.

Drug toxicity is often the cause of adverse side effects in the drug-food interaction. Other food-drug interactions are not as dramatic as the "cheese reaction." Still, there are other interactions that you should be aware of:

  • Grapefruit juice has a very broad spectrum of competing drug effects. It inhibits the drug-metabolizing enzyme CYP3A4 in the intestines. Complicating matters in elderly people is the issue of "polypharmacy," taking numerous medications along with a high consumption of grapefruit juice. Calcium channel blockers, cholesterol medications, some psychiatric medications, estrogen, oral contraceptives and many allergy medications are affected by grapefruit juice.
  • Alcohol can overwhelm the liver as it stops metabolizing drugs and starts converting the alcohol instead. This leads almost universally to drug toxicity and possibly even overdosage.
  • Caffeine stimulates the central nervous system and certain drugs amplify its jittery, excitable effects. Bronchodilators (like theophylline and albuterol) and quinolone antibiotics (like ciprofloxacin)

It is ironic that certain things in our diet like cheese, beans, miso soup, grapefruit juice, caffeine and alcohol increase the concentration of drugs. You'd think that would be a good thing... but it is a tricky business, titrating drug concentrations to specific doses that are effective without being harmful. Leave the drug dose tampering up to the doctors and pharmacologists.

Be sure to check the instructions of any new medications you take to be sure that you're being safe! :)

The sites I checked out:

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