Levothyroxine, Oral

What are other names for this medicine?

Type of medicine: thyroid hormone

Generic and brand names: levothyroxine, oral; Eltroxin; Levo-T; Levotabs; Levothroid; Levoxine; Levoxyl; Synthroid; Thyrx; Unithroid

What is this medicine used for?

This medicine is taken by mouth to treat hypothyroidism (when your body does not produce enough thyroid hormone).

What should my health care provider know before I take this medicine?

Before taking this medicine, tell your health care provider if you have:

• adrenal gland problems
• diabetes
• heart disease
• high blood pressure.

Females of childbearing age: Tell your health care provider if you are pregnant or plan to become pregnant. Do not breast-feed while taking this medicine without your health care provider's approval.

How do I take it?

Take this medicine exactly as directed by your health care provider. Do not take more or less of it or take it longer than prescribed. Do not stop taking this medicine without your health care provider's approval.

It is best to take this medicine on an empty stomach, 30 minutes before you eat or 2 hours after you eat.

Do not miss a dose. If you miss a dose, take it as soon as you remember unless it is almost time for the next scheduled dose. In that case, skip the missed dose and take the next one as directed. Do not take double doses. If you are not sure of what to do if you miss a dose, or if you miss more than one dose, contact your health care provider.

What should I watch out for?

You will feel different when you start taking this medicine. Tell your health care provider if any ill feelings continue or get worse.

This medicine may cause chest pain when you exercise. Tell your health care provider if you have chest pain.

If you need emergency care, surgery, or dental work, tell the health care provider or dentist you are taking this medicine.

What are the possible side effects?

Along with its needed effects, your medicine may cause some unwanted side effects. Some side effects may be very serious. Some side effects may go away as your body adjusts to the medicine. Tell your health care provider if you have any side effects that continue or get worse.

Serious (report these to your health care provider right away): Chest pain, trouble breathing, rash, irregular heartbeat.

Other: Diarrhea, weight loss, change in appetite, headache, irritability, heavy sweating, change in menstrual periods.

What products might interact with this medicine?

When you take this medicine with other medicines, it can change the way this or any of the other medicines work. Nonprescription medicines, vitamins, natural remedies, and certain foods may also interact. Using these products together might cause harmful side effects. Talk to your health care provider if you are taking:

• antacids or vitamins that contain aluminum, magnesium, or iron (Take them 2 to 3 hours before or after you take this medicine.)
• antihistamines (for example, hay fever products), decongestants such as pseudoephedrine (Sudafed), and diet medicines
• blood thinners as warfarin (Coumadin)
• cholestyramine (Questran) and colestipol (Colestid) (take them 4 to 5 hours apart from this medicine)
• digitalis, digoxin (Lanoxin), digitoxin (Crystodigin)
• estrogens such as Premarin, Estrace, Estinyl, Estraderm, and birth control pills
• insulin and oral medicines for diabetes
• medicines for seizures such as carbamazepine (Tegretol), phenobarbital, and phenytoin (Dilantin)
• sucralfate (Carafate)
• selective serotonin reuptake inhibitors (SSRIs) such as fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft)
• tricyclic antidepressants such as amitriptyline (Elavil), nortriptyline (Aventyl, Pamelor), imipramine (Tofranil), and doxepin (Sinequan).

Keep a list of all your medicines (prescription, nonprescription, supplements, natural remedies, and vitamins) with you. Be sure that you tell all health care providers who treat you about all the products you are taking.

How should I store this medicine?

Store this medicine at room temperature. Keep the container tightly closed. Protect it from heat, high humidity, and bright light.

This advisory includes selected information only and may not include all side effects of this medicine or interactions with other medicines. Ask your health care provider or pharmacist for more information or if you have any questions.

Ask your pharmacist for the best way to dispose of outdated medicine or medicine you have not used. Do not throw medicine in the trash.

Keep all medicines out of the reach of children.

Do not share medicines with other people.