Synthroid, 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, Synthroid
reverses these symptoms. Synthroid also is used to treat congenital
hypothyroidism (cretinism) and goiter (enlarged thyroid gland).
Synthroid is sometimes prescribed for other uses;
ask your doctor or pharmacist for more information.
How
should Synthroid be used?
Synthroid comes as a tablet to take by mouth. It usually is taken
as a single dose before breakfast every day. To control the symptoms
of hypothyroidism, you probably will need to take this medicine for
the rest of your life. It may take about 2 weeks before you notice
any change in your symptoms. Follow the directions on your
label carefully, and ask your doctor or pharmacist to explain any
part you do not understand. Take Levothyroxine
exactly as directed. Do not take more or less of it or take it more
often than prescribed by your doctor. Continue to take Synthroid even
if you feel well. Do not stop taking Levothyroxine
without talking to your doctor. Synthroid : Full
Prescribing Information
Before
taking Levothyroxine, -- tell your doctor and pharmacist if you are
allergic to Synthroid, 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.
-- tell your doctor and pharmacist what
medications you are taking, especially amphetamines; antacids; 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; cholesterol-lowering
resins such as cholestyramine (Questran) or colestipol (Colestid);
diabetes medications (insulin and tablets); digoxin (Lanoxin); estrogens;
iron; methadone; oral contraceptives; phenytoin (Dilantin); sodium
polystrene sulfonate (Kayexalate); sucralfate (Carafate); steroids;
theophylline (TheoDur); and vitamins.
-- if you take cholestyramine (Questran) or colestipol (Colestid),
take it at least 4 hours before or 1 hour after taking Synthroid.
-- tell your doctor if you have or have ever had 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.
-- tell your doctor if you are pregnant, plan to become pregnant or
are breast-feeding. If you become pregnant while taking Synthroid,
call your doctor.
-- if you have surgery, including dental surgery, tell the doctor
or dentist that you are taking Synthroid.
What should I do if I forget a dose?
Take the missed dose as soon as you remember it. However, if it is
almost time for the next dose, skip the missed dose and continue your
regular dosing schedule. Do not take a double dose to make up for
a missed one.
What
side effects can Synthroid cause?
Although side effects from Levothyroxine are not common, they can
occur. Tell your doctor if any of these symptoms are severe or do
not go away:
- weight loss
- tremor
- headache
- upset stomach
- vomiting
- diarrhea
- stomach cramps
- nervousness
- irritability
- insomnia
- excessive sweating
- increased appetite
- fever
- changes in menstrual cycle
- sensitivity to heat
- temporary hair loss, particularly in children during the first
month of therapy
If you experience either of the following symptoms,
call your doctor immediately:
- chest pain (angina)
- rapid or irregular heartbeat or pulse
What storage conditions are needed for Synthroid?
Keep Levothyroxine
in the container it came in, tightly closed, and out of reach of
children. Store it at room temperature and away from excess heat
and moisture (not in the bathroom). Throw away any medication that
is outdated or no longer needed. Talk to your pharmacist about the
proper disposal of your medication.
What other information should I know?
Keep all appointments with your doctor and the laboratory.
Your doctor will order certain lab tests to check your response
to Synthroid.
Learn the brand name and generic name of your medication.
Do not switch brands without talking to your doctor or pharmacist,
as each brand of Levothyroxine
contains a slightly different amount of medication.
Do not let anyone else take your medication. Ask
your pharmacist any questions you have.