Most of us have heard that certain medicines, when taken together, can be potentially harmful. But what about food and medicine? What possible harm could come from eating a cheese sandwich after taking an antibiotic? You may be surprised to learn that certain foods can dramatically affect your medicines.
Knowing how and when to take your medicines can eliminate or reduce interactions between food and drugs. Your pharmacist and your doctor can provide you with the most up-to-date information about these interactions.
Take this quick quiz to check your knowledge of food and drug interactions.
Answer true or false for each of the following eight questions.
medicine should always be taken with meals—False
The size and composition of a meal determines how quickly your medicine will be absorbed. Some medicines, such as aspirin and nonsteroidal anti-inflammatory drugs (eg, ibuprofen) irritate the stomach lining if you take them on an empty stomach. Other medicines, however, should be taken on an empty stomach. Food may slow their digestion or absorption. This is particularly true of some antibiotics.
Only prescription drugs interact with food—False
Over-the-counter medicines that you buy without a prescription, such as aspirin and low doses of ibuprofen, often interact with food. Watch out for alcohol, too. It blocks the effects of some drugs and intensifies the effects of others to dangerous levels. For example, alcohol combined with nitroglycerin can dangerously lower blood pressure. If you are taking antibiotic metronidazole (Flagyl), you may need to avoid alcohol completely.
It's safe to take my medicines with a glass of milk—False
Some drugs are negatively affected by dairy products. For example, the calcium in milk binds up tetracycline, a commonly prescribed antibiotic, so less tetracycline is absorbed. To prevent this, tetracycline should be taken at least two hours before or after eating dairy products or taking calcium supplements.
high blood pressure
medicine. Therefore, I should use a potassium-containing salt substitute—False
This can sometimes be a dangerous misconception. Some blood pressure medicines (eg, furosemide) cause you to lose potassium, so your doctor may prescribe a potassium supplement. However, other classes of blood pressure medicines actually prevent potassium loss. If you take potassium-sparing diuretics or ACE inhibitors, avoid liberal use of salt substitutes that contain potassium. Excessive use of these products causes an accumulation of potassium, which can lead to severe complications that can threaten your health or life.
Mineral oil is a harmless, gentle laxative—False
Although gentle, mineral oil is a fat-soluble liquid. Mineral oil goes through the body undigested, robbing the body of fat-soluble vitamins like A, D, and E.
Any pharmacy can fill my prescriptions—True
Any pharmacy can fill your prescriptions. However, it makes more sense to fill all your prescriptions at the same pharmacy. This enables the pharmacy's computer to keep track of all your medicines so that the pharmacist can note any potential cross-reactions between existing medicines and new ones. By visiting the same pharmacy all the time, you also create a relationship with the pharmacist. This makes you more likely to discuss any concerns you have.
Grapefruit juice is a harmless, healthy source of
Grapefruit juice is healthy on its own, but it can interact with numerous medicines, potentially reducing their effects or increasing the risk of toxicity.
In addition to food and drug interactions, certain medicines also affect taste, sensation, and appetite. For example, penicillin can make foods "taste funny." Antihistamines and certain antidepressants can cause dry mouth, making it hard to chew and swallow. Certain pain medicines and iron supplements are a frequent cause of constipation.
How do you know when and how medicines should be taken? Read the directions printed on the container and ask your doctor or pharmacist. Food and drug interactions are almost always avoidable or manageable.
To keep food-drug interactions at a minimum, follow these tips:
US Food and Drug Administration
Canadian Institutes of Health Research
Antidepressant medication overview. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated March 28, 2012. Accessed July 7, 2012.
Antihypertensive medications overview. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated May 29, 2012. Accessed July 7, 2012.
Avoid food-drug interactions. National Consumer League website. Available at: http://www.natlcon.... Accessed July 7, 2012.
Drug interactions: what you should know. Center for Drug Evaluation and Research website. Available at: http://www.fda.gov/Drugs/ResourcesForYou/ucm163354.htm. Updated April 30, 2012. Accessed July 7, 2012.
Mineral oil. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated December 14, 2011. Accessed July 7, 2012.
Tetracycline. EBSCO DynaMed website. Available at: http://www.ebscohost.com/dynamed. Updated December 14, 2011. Accessed July 7, 2012.
Last reviewed July 2012 by Brian P. Randall, MD
Last Updated: 7/7/2012
Copyright © 2013 EBSCO Publishing All rights reserved.
Sponsored by iHerb.Com
Positively the best overall value for natural products!