Nutrition and drug interaction

Jenifer Theresal J

Senior Dietician, Kauvery Hospital, Tennur, Trichy, India

Nutrition and drug interaction

Abstract

The effect of drug on a person may be different than expected because that drug interacts with another drug the person is taking (drug-drug interaction), food, beverages, dietary supplements the person is consuming (drug-nutrient/food interaction) or another disease the person has (drug-disease interaction). Major side-effects of some diet (food) on drugs include alteration in absorption by fatty, high protein and fiber diets.

Background

Medicines can treat and cure many health problems. However, they must be taken properly to ensure that they are safe and effective. Medications should be extremely specific in their effects, have the same predictable effect for all patients, never be affected by concomitant food or other medications, exhibit linear potency, be totally non-toxic in any dosage and require only a single dose to effect a permanent cure. However, this ideal drug is still to be discovered. Interactions between food and drugs may inadvertently reduce or increase the drug effect. Some commonly used herbs, fruits, as well as alcohol, may cause failure of the therapy up to the point of serious alterations of the patient’s health.

Antibiotics and Dairy Products

Dairy products such as milk, yogurt, and cheese can delay or prevent the absorption of antibiotics such as tetracyclines and ciprofloxacin (Cipro). This occurs because the calcium in such foods binds to the antibiotics in the stomach and upper small intestine to form an insoluble compound.

To avoid problems, it is recommended to take an antibiotic one hour before or two hours after a meal.

However, there’s no need to avoid milk and dairy with all antibiotics.

For example, it’s recommended that metronidazole (Flagyl) should be taken with water or milk to prevent stomach upset.

Digoxin, High-Fiber Diets, and Herbs

Digoxin (Digitalis, Digitek, Lanoxin) is used to strengthen the contraction of the heart muscle, slow the heart rate, and promote the elimination of fluid from body tissues.

Dietary fiber, specifically insoluble fiber such as wheat bran, can slow down the absorption of digoxin and lessen its effectiveness. To prevent this, elders should take digoxin at least one hour before or two hours after eating a meal.

Herb use can also affect digoxin. For example, ginseng can elevate blood levels of digoxin by as much as 75%, while St. John’s Wort decreases blood levels of this drug by 25%.

It’s important for the patient to recognize signs of digoxin toxicity. These include a yellow tint to vision and the appearance of halos around objects, as well as weakness, confusion, dizziness, and nausea and vomiting.

Anti-thyroid Drugs and Iodine-Rich Foods

Anti-thyroid drugs are compounds that interfere with the body’s production of thyroid hormones, thereby reducing the symptoms of hyperthyroidism. According to a broad body of research, Americans’ high-iodine diets account for the lower remission rate of hyperthyroidism in those who are prescribed anti-thyroid drugs.

Anti-thyroid drugs work by preventing iodine absorption in the stomach. A high-iodine diet requires higher doses of anti-thyroid drugs. The higher the dose of anti-thyroid drugs, the greater the incidence of side effects that include rashes, hives, and liver disease.

The richest dietary sources of iodine are seafood and seaweed. Iodine is also found in iodized salt and to a lesser extent in eggs, meat, and dairy products.

Anti-tubercular Drugs

Anti-tubercular drugs like isoniazid have interaction substances that contain tyramine and histamine. High-fat meals decrease the serum concentration of cycloserine, a bacteriostatic anti-tubercular drug and result in incomplete eradication of bacteria.

Some significant Food-Drug Interactions

Drugs	Food	Drug-Food Interaction
WARFARIN	High-protein diet	raise serum albumin levels, and decrease in international normalized ratio (INR)
	Vegetables containing vitamin k	interferes with the effectiveness and safety of warfarin therapy.
	Charbroiled foods	decrease warfarin activity
	Cooked onions	increase warfarin activity
	Cranberry juice	elevates INR without bleeding in elderly patient
	Leafy green vegetables	Reduce efficacy of anticoagulation, thromboembolic complications may develop
Monoamine Oxidases	Tyramine-containing food	hypertensive crisis
Propranolol	Rich protein food	serum level may be increased
Celiprolol	Orange juice	the intestinal absorption is inhibited
ACES Inhibitors	Empty stomach	absorption is increased
CA2 Channel	Grape fruit juice	increases the bio availability
Antibiotics	with milk products	that complex with some antibiotics and prevent their absorption. reduced bio availability
Acetaminophen	Pectin	delays its absorption and onset
Theophyline	High-fat meal and grape fruit juice	increase bio availability
Theophyline	Caffeine	increases the risk of drug toxicity
Esomeprazole	High-fat meal	Bioavailability was reduced
Cimetidine, rupatadine	with food (any type)	increase bioavailability
Isoniazide	Plants, medicinal herbs, oleanolic acid	exerts synergistic effect
Cycloserine	High-fat meals	decrease the serum concentration
Acarbose	at the start of each meal	maximum effectiveness
Mercaptopurine	Cow’s milk	reduce bioavailability
Tamoxifen	Sesame seeds	negatively interferes with tamoxifen in inducing regression of established mcf-7 tumor size but beneficially interacts with tamoxifen on bone in ovariectomized athymic mice
Levothyroxine	Grapefruit juice	delay the absorption

Reference

Frankel EH. Basic Concepts. In: Hand book of food-drug Interactions, McCabe BJ, Frankel EH., Wolfe JJ (Eds.) pp. 2, CRC Press, Boca Raton, 2003.

Ayo JA, et al. Food and drug interactions: its side effects. Nutr Food Sci. 2005;35(4):243-252.

Jenifer Theresal J

Senior Dietician

Nutrition and drug interaction

Jenifer Theresal J