Before Using This Medicine

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For tetracyclines, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to any of the tetracyclines or combination medicines containing a tetracycline. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes. In addition, if you are going to be given oxytetracycline by injection, tell your doctor if you have ever had an unusual or allergic reaction to ``caine-type'" anesthetics (e.g., lidocaine).

Pregnancy—Use is not recommended during the last half of pregnancy. If tetracyclines are taken during that time, they may cause the unborn infant's teeth to become discolored and may slow down the growth of the infant's teeth and bones. In addition, liver problems may occur in pregnant women, especially those receiving high doses by injection into a vein.

Breast-feeding—Use is not recommended since tetracyclines pass into breast milk. They may cause the nursing baby's teeth to become discolored and may slow down the growth of the baby's teeth and bones. They may also increase the sensitivity of nursing babies" skin to sunlight and cause fungus infections of the mouth and vagina. In addition, minocycline may cause dizziness, light-headedness, or unsteadiness in nursing babies.

Children—Tetracyclines may cause permanent discoloration of teeth and slow down the growth of bones. These medicines should not be given to children 8 years of age and younger unless directed by the child's doctor.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults or if they cause different side effects or problems in older people. There is no specific information comparing use of tetracyclines in the elderly with use in other age groups.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are taking tetracyclines, it is especially important that your health care professional know if you are taking any of the following:

• Antacids or
• Calcium supplements such as calcium carbonate or
• Cholestyramine (e.g., Questran) or
• Choline and magnesium salicylates (e.g., Trilisate) or
• Colestipol (e.g., Colestid) or
• Iron-containing medicine or
• Laxatives (magnesium-containing) or
• Magnesium salicylate (e.g., Magan)—Use of these medicines with tetracyclines may decrease the effect of tetracyclines

• Oral contraceptives (birth control pills) containing estrogen—Use of birth control pills with tetracyclines may decrease the effect of the birth control pills and increase the chance of unwanted pregnancy
• Penicillins—Use of tetracyclines with penicillins may decrease the effect of penicillins

Other medical problems—The presence of other medical problems may affect the use of tetracyclines. Make sure you tell your doctor if you have any other medical problems, especially:

• Diabetes insipidus (water diabetes)—Demeclocycline may make the condition worse

• Kidney disease (does not apply to doxycycline or minocycline)—Patients with kidney disease may have an increased chance of side effects

• Liver disease—Patients with liver disease may have an increased chance of side effects if they use doxycycline or minocycline