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 thyroid hormones, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to thyroid hormones. Also tell your health care professional if you are allergic to any other substances, such as foods, preservatives, or dyes.

Pregnancy—Use of proper amounts of thyroid hormone during pregnancy has not been shown to cause birth defects or other problems. However, your doctor may want you to change your dose while you are pregnant. This will make regular visits to your doctor important.

Breast-feeding—Use of proper amounts of thyroid hormones by mothers has not been shown to cause problems in nursing babies.

Children—Thyroid hormones have been tested in children and have not been shown to cause different side effects or problems in children than they do in adults.

Older adults—This medicine has been tested and has not been shown to cause different side effects or problems in older people than it does in younger adults. However, a different dose may be needed in the elderly. Therefore, it is important to take the medicine only as directed by the doctor.

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 thyroid hormones, it is especially important that your health care professional know if you are taking any of the following:

• Amphetamines

• Anticoagulants (blood thinners)

• Appetite suppressants (diet pills)

• Cholestyramine (e.g., Questran)

• Colestipol (e.g., Colestid)

• Medicine for asthma or other breathing problems

• Medicine for colds, sinus problems, or hay fever or other allergies (including nose drops or sprays)

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

• Diabetes mellitus (sugar diabetes)

• Hardening of the arteries

• Heart disease

• High blood pressure

• Overactive thyroid (history of)

• Underactive adrenal gland

• Underactive pituitary gland