Consumer Medicine Information
Levothyroxine tablets 50 microgram and 100 microgram
What is in this leaflet
Please read this leaflet carefully before you start taking Levothyroxine tablets.
This leaflet answers some common questions about Levothyroxine tablets. It does not contain all of the available information. It does not take the place of talking to your doctor or pharmacist.
All medicines have risks and benefits. Your doctor has weighed the expected benefits of you taking Levothyroxine tablets against the risks this medicine could have for you.
If you have any concerns about taking this medicine, ask your doctor or
Keep this leaflet with your medicine.
You may need to read it again.
What Levothyroxine tablets are used for
Levothyroxine tablets contain the active ingredient levothyroxine. Levothyroxine belongs to a small group of medicines called thyroid hormones, which work by replacing the body's low levels of thyroxine.
Levothyroxine tablets are used to treat hypothyroidism, a disease in which the thyroid gland is underactive and does not produce enough thyroxine, a hormone, which is important for controlling your metabolism. Symptoms of hypothyroidism include tiredness, muscle weakness, cramps, feeling the cold, a slow heart rate, dry and flaky skin, hair loss, a deep husky voice and weight gain.
Levothyroxine tablets are also used to treat children born with hypothyroidism (congenital), those who develop hypothyroidism in the first year of life (neonatal) and children who have hypothyroidism as part of juvenile myxoedema, a condition in which the amount of thyroxine produced by the body is low.
Ask your doctor if you have any questions about why Levothyroxine tablets have
been prescribed for you.
Your doctor may have prescribed Levothyroxine tablets for another reason.
This medicine is available only with a doctor's prescription.
Before you take Levothyroxine tablets
When you must not take it
Do not take Levothyroxine tablets if:
• you have had an allergic reaction before to any of the ingredients in
Levothyroxine tablets listed at the end of this leaflet
• you have thyrotoxicosis, a disease in which the thyroid gland is overactive and
• the packaging is torn or shows signs of interference, or the tablets look damaged
Do not take it after the expiry date printed on the pack.
If you take it after the expiry date has passed, it may not work as well. If the pharmacist
has repacked the medicine for you, there may not be an expiry date on the pack. If you are not sure whether you should start taking Levothyroxine tablets, talk to
Before you start to take it
Tell your doctor if:
• you are allergic to any of the ingredients in Levothyroxine tablets listed at the end
• you are allergic to any other medicines, foods, dyes or preservatives • you have any other health problems, especially:
• diabetes • heart disease • high blood pressure • underactive adrenal glands.
Tell your doctor if you are pregnant or plan to become pregnant.
Levothyroxine is not thought to be harmful to an unborn baby when taken by a pregnant
woman. However, thyroxine levels need to be watched carefully during pregnancy
because too much or too little thyroxine in the mother's bloodstream could affect the
well-being of an unborn baby.
Also tell your doctor if you are breastfeeding or planning to breastfeed.
Although the active ingredient in Levothyroxine tablets, levothyroxine, passes into
breast milk, it is not likely to have a harmful effect on a baby. However, it might interfere
with the results of tests to detect congenital hypothyroidism in the baby. You should not
breastfeed unless your doctor says you can.
If you have not told your doctor about any of the above, please do so before you
start taking Levothyroxine tablets.
Taking other medicines
Tell your doctor if you are taking any other medicines, including medicines that
you buy without a prescription from a pharmacy, supermarket or health food
shop. You should tell any health professional who is prescribing a new medicine
for you that you are taking Levothyroxine tablets.
Some medicines may interfere with Levothyroxine tablets. These include:
• anticoagulants, medicines used to thin your blood and treat blood clots • medicines for epilepsy (e.g. phenytoin, carbamazepine) • medicines used to treat depression • cardiac glycosides, for example digoxin (LanoxinTM), used to treat heart problems • medicines used to lower blood cholesterol levels such as statins (e.g.
simvastatin, lovastatin), bile acid sequestrants (e.g. colestipol), cholestyramine (Questran), and clofibrate
• androgens (male hormones) and anabolic steroids (body building hormones) • antacids (medicines used to treat heartburn and indigestion), such as aluminium
• cation exchange resins, e.g. Kayexalate • sucralfate, used to treat ulcers • calcium carbonate and ferrous sulphate • tamoxifen, imatinib and 5-fluorouracil, used to treat certain types of cancer • methadone, used to treat pain • amiodarone, a medicine used to treat irregular heart beat • medicines to relieve asthma attacks • medicines used for weight reduction • the oral contraceptive pill.
These medicines may be affected by Levothyroxine tablets, or may affect how well it works. You may need different amounts of your medicine, or you may need to take different medicines.
Your doctor or pharmacist has more information on medicines to be careful with or to avoid while taking Levothyroxine tablets.
How to take Levothyroxine tablets
How much to take
Take Levothyroxine tablets exactly as your doctor has prescribed.
Your doctor will tell you how many Levothyroxine tablets to take each day. Your doctor will calculate the dose based on your weight.
Never take more tablets than your doctor has prescribed.
Your doctor may vary your dose depending on how you respond to Levothyroxine tablets.
In adults, the usual dose is 50
microgram to 100 microgram daily, increased every 4 to 6 weeks as needed. The maximum dose is 200 microgram daily.
The dose in children is reduced according to their weight and age.
Elderly people usually need a smaller dose because they are more sensitive to the effects of levothyroxine.
Your doctor will do regular blood tests to make sure levothyroxine is working for you.
How to take it
Swallow tablets whole with a glass of water.
Tablets should be taken on an empty stomach, preferably at least 30 minutes before
How long to take it
Many people need treatment with Levothyroxine tablets long term.
If you forget to take it
Do not take an extra dose. Wait until the next dose and take your normal dose
Do not try to make up for the dose that you missed by taking more than one dose
at a time.
If you are not sure what to do, ask your doctor or pharmacist.
While you are taking Levothyroxine tablets
Things you must do
Tell all doctors and pharmacists involved in your healthcare that you are taking
If you are about to be started on any new medicine, tell your doctor and
pharmacist that you are taking Levothyroxine tablets.
Tell your doctor if you are pregnant or planning to become pregnant or are
breastfeeding while taking Levothyroxine tablets.
Tell your doctor if, for any reason, you have not taken Levothyroxine tablets
exactly as prescribed.
Otherwise, your doctor may think it is not working for you and change your
Levothyroxine tablets dose unnecessarily.
Tell your doctor if you feel that Levothyroxine tablets are not helping your
Things you must not do
Do not stop taking Levothyroxine tablets or change the dose without first
checking with your doctor, or your symptoms could return.
Do not let yourself run out of medicine over the weekend or on holidays.
Do not give Levothyroxine tablets to anyone else, even if they have the same
condition as you.
Do not take any other medicines, whether they require a prescription or not,
without first asking your doctor or a pharmacist.
Things to be careful of
Do not drive or operate machinery until you know how your Levothyroxine tablets
dose is affecting you.
In case of overdose
If you take too much (overdose)
Immediately telephone your doctor, or the National Poisons Centre [telephone
0800 POISON or 0800 764 766], or go to Accident and Emergency at your nearest
hospital, if you think that you or anyone else may have taken too much
Do this even if there are no signs of discomfort or poisoning.
You may need urgent medical attention.
Keep phone numbers for these places handy.
An overdose of Levothyroxine tablets can cause agitation, confusion, irritability, hyperactivity, sweating, headaches, fever, widened pupils, fits, palpitations and diarrhoea.
Tell your doctor or pharmacist as soon as possible if you do not feel well while
you are taking Levothyroxine tablets.
All medicines can have side effects. Sometimes they are serious, most of the time they are not. You may need medical treatment if you get some of the side effects.
Ask your doctor or pharmacist to answer any questions you may have.
TELL YOUR DOCTOR IMMEDIATELY if you think you are having an allergic
(hypersensitivity) reaction to Levothyroxine tablets.
• severe skin rash, itching or hives • swelling of the face, lips, mouth or throat • difficulty breathing or swallowing • fever • low blood pressure (feeling faint or dizzy).
However, these symptoms do not necessarily mean that you are allergic to Levothyroxine tablets.
Tell your doctor if you notice any of the following:
• diarrhoea • nausea • vomiting • irregular or fast heart beat • chest pain • sweating, flushing • weight loss • muscle weakness/cramps, tremors • rapid breathing • fever • constantly feeling hungry • abdominal pain • headache • inability to sleep • feeling restless/excited • hair loss • irregular period in women • Intolerance to heat • difficulty in conceiving (carrying a child).
The above side effects are rare and usually mean that your daily Levothyroxine tablets dose is too high.
Children taking Levothyroxine tablets may experience partial loss of hair during the first few months of therapy, but this effect is usually temporary and subsequent regrowth usually occurs.
Tell your doctor if you notice any other effects.
Other adverse effects not listed above may also occur in some patients.
Do not be alarmed by this list of possible adverse effects.
You may not experience any of them.
After taking Levothyroxine tablets
Keep your tablets in the blisters until it is time to take them.
If you take the tablets out of the blisters they may not keep well.
Keep Levothyroxine tablets in a cool dry place away from light where the
temperature stays below 25°C.
Do not store Levothyroxine tablets or any other medicine in a bathroom or near a sink.
Do not leave it in a car or on a window sill.
Heat and dampness can destroy some medicines.
Keep Levothyroxine tablets where young children cannot reach it.
A locked cupboard at least one and a half meters above the ground is a good place to
If your doctor tells you to stop taking Levothyroxine tablets, or the medicine has passed
its expiry date, ask your pharmacist what to do with any tablets that are left.
What it looks like
• Levothyroxine 50
microgram tablets are white, uncoated, biconvex tablets,
engraved with FW21 on one face with a breakline on the other.
• Levothyroxine 100
microgram tablets are white, uncoated, biconvex tablets,
engraved with FW31 on one face with a breakline on the other.
50 microgram tablets
100 microgram tablets
Inactive ingredients: • sodium citrate
Your doctor is the best person to give you advice on the treatment of your illness. You may also be able to find general information about hypothyroidism and its treatment from other sources, for example, books in public libraries and on the Internet.
Levothyroxine tablets are supplied in New Zealand by:
Boucher & Muir (NZ) t/a Mercury Pharma (NZ) 39 Anzac Road Browns Bay Auckland 0753
Date of Preparation
This leaflet was prepared in April 2012.
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