Levothyroxine

CAUTION:

Thyroid hormone should not be used to treat obesity in patients with normal thyroid function. Levothyroxine is ineffective for weight reduction in normal thyroid patients and may cause serious or life-threatening toxicity, especially when taken with amphetamines. Talk to your doctor about the potential risks associated with this medication.

General Information and Indications:

Levothyroxine, a thyroid hormone, is used to treat hypothyroidism, a condition where the thyroid gland does not produce enough thyroid hormone. Without this hormone, the body cannot function properly, resulting in poor growth, slow speech, lack of energy, weight gain, hair loss, dry thick skin, and increased sensitivity to cold. When taken correctly, levothyroxine reverses these symptoms. Levothyroxine is also used to treat congenital hypothyroidism (cretinism) and goiter (enlarged thyroid gland).
 

Information For Users:

Levothyroxine comes as a tablet to take by mouth. It is usually taken once a day on an empty stomach, 1/2 to 1 hour before breakfast . Follow the directions on your prescription label, ask your doctor or pharmacist If you have any questions. Take levothyroxine exactly as directed. Do not take more or less of it or take it more often than prescribed by your health care provider.

The tablets may get stuck in your throat or cause choking or gagging; therefore, the tablet should be taken with a full glass of water.

If you are giving levothyroxine to an infant or child who cannot swallow the tablet, crush the tablet and mix it in 1 to 2 teaspoons of plain water. Give this mixture by spoon or dropper right away. Do not store this mixture. Only mix the crushed tablets with water. Do not mix with food or soybean infant formula.

Your doctor will probably start you on a low dose of levothyroxine and slowly increase your dose.

Levothyroxine controls hypothyroidism, but does not cure it. It may take several weeks before you notice a change in your symptoms. Continue taking levothyroxine even if you feel well. Do not discontinue taking levothyroxine without informing your doctor.

special precautions:

o Inform your doctor or pharmacist if you have allergy to levothyroxine, thyroid hormone, any other drugs, povidone iodine, tartrazine (a yellow dye in some processed foods and drugs), or foods such as lactose or corn starch. Levothroid and Eltroxin contain lactose, while Synthroid contains tartrazine and povidone. Eltroxin contains corn starch.
o Inform your doctor and pharmacist what prescription and nonprescription medications you are taking, especially amphetamines; anticoagulants ('blood thinners') such as warfarin (Coumadin); antidepressants or anti-anxiety agents; arthritis medicine; aspirin; beta-blockers such as metoprolol (Lopressor, Toprol), propranolol (Inderal) or timolol (Blocadren, Timoptic); cancer chemotherapy agents; diabetes medications (insulin and tablets); digoxin (Lanoxin); estrogens; iron; methadone; oral contraceptives; phenytoin (Dilantin); steroids; theophylline (TheoDur); and vitamins.
o if you take an antacid, calcium carbonate (Tums), cholestyramine (Questran), colestipol (Colestid), iron, sodium polystrene sulfonate (Kayexalate), simethicone (Phazyme, Gas X), or sucralfate (Carafate), take it at least 4 hours before or 4 hours after you take levothyroxine.
o inform your doctor if you are breast-feeding diabetes; hardening of the arteries (atherosclerosis); kidney disease; hepatitis; cardiovascular disease such as high blood pressure, chest pain (angina), arrhythmias, or heart attack; or an underactive adrenal or pituitary gland.
o Inform your doctor if you are pregnant, plan to become pregnant or are breast-feeding. If you become pregnant while taking levothyroxine, call your doctor.
o if you have surgery, including dental surgery, Inform your doctor or dentist that you are taking levothyroxine.

Possible Adverse Effects:

Though adverse effects of levothyroxine are not common, they could occur. Inform your doctor if any of the following symptoms are severe or do not go away:

o weight loss
o tremor
o headache
o upset stomach
o vomiting
o diarrhea
o stomach cramps
o nervousness
o irritability
o insomnia (sleeplessness)
o excessive sweating (hyperhidrosis)
o increased appetite
o fever
o changes in menstrual cycle
o sensitivity to heat
o temporary hair loss, particularly in children during the first month of therapy

If you experience either of the following symptoms, call your doctor without delay:

o chest pain (angina)
o rapid or irregular heartbeat or pulse

Brand Name(s):

o Levothroid®
o Levoxyl®
o Synthroid®
o Unithroid®