What Is a Food-Drug Interaction?Any time that a food or beverage changes the effects of a drug, the change is considered a food-drug interaction. Food-drug interactions can occur with prescription drugs, over-the-counter drugs, herbal products, and dietary supplements.

Drug Interaction : 

 Tetracycline should not be taken at the same time as aluminum, magnesium, or calcium-based antacids (for example,aluminum with magnesium hydroxide-oral [Mylanta, Maalox], calcium carbonate [Tums, Rolaids]); iron supplements; bismuth subsalicylate (Pepto-Bismol), and dairy products. These agents bind tetracycline in the intestine and reduce its absorption into the body.

Tetracycline may enhance the activity of the blood thinner, warfarin(Coumadin), and result in excessive "thinning" of the blood, necessitating a reduction in the dose of warfarin. Phenytoin (Dilantin), carbamazepine(Tegretol), and barbiturates (such as phenobarbital) may enhance the elimination of tetracycline and reduce the effectiveness of tetracycline. Tetracycline may reduce the effectiveness of oral contraceptives.

PREGNANCY: Tetracycline antibiotics can impair development of bone in the fetus. Therefore, tetracycline is not recommended during pregnancyunless there is no other appropriate antibiotic.

NURSING MOTHERS: Tetracycline is secreted into breast milk. Since tetracycline can impair the development of bone in infants, nursing mothers should not use tetracycline.