Skip to Content



View full screen / Print PDF » Download PDF ⇩

Levothyroxine sodium 25 micrograms Tablets
(levothyroxine sodium)

Read all of this leaflet carefully before you start taking
this medicine.
Keep this leaflet. You may need to read it again. If you have any
further questions, ask your doctor or pharmacist. This medicine has
been prescribed for you. Do not pass it on to others. It may harm
them, even if their symptoms are the same as yours.

The name of your medicine is Levothryoxine sodium 25 micrograms
tablets. It will be referred to as Levothryoxine Tablets for ease
throughout the leaflet.

• Thyroxine is a hormone produced by the thyroid gland.
Levothyroxine is used to replace the thyroxine in people
whose thyroid gland does not work properly. You will
usually need to take this medicine for the rest of your life
and must not stop taking it, or change the dose, without
speaking to your doctor first.
• This medicine can affect the way other medicines work
(See Section 2 ‘Taking other medicines’). If you take
medicines to control diabetes or warfarin to prevent clots,
the dose may need to be adjusted by your doctor when
you start taking levothryoxine tablets.
• You will start off taking a low dose of this medicine (See
Section 3 ‘How to take’). Your doctor will then increase
the dose gradually at 3 - 4 week intervals until your
thyroxine levels are corrected. This will help to reduce the
chance of side effects.
• You will need regular blood tests whilst you are taking this
• These tablets can be taken by both adults and children.
If you are giving this medicine to your child make sure
you know how many and when to give the tablets (See
Section 3 ‘How to take’) and what side effects to look out
for (See Section 4 ‘Possible side effects’).
In this leaflet:
1. What Levothyroxine Tablets are and what they are used for
2. Before you take Levothyroxine Tablets
3. How to take Levothyroxine Tablets
4. Possible side effects
5. How to store Levothyroxine Tablets
6. Further information


Thyroxine is a hormone which is produced naturally in the body by the
thyroid gland. Levothyroxine is a synthetic version of this hormone.
Thyroxine controls how much energy your body uses. When the
thyroid gland does not produce enough thyroxine (a condition known
as hypothyroidism), many of the body’s functions slow down. Some of
the most common symptoms of hypothyroidism are:
• tiredness
• weight gain
• feeling depressed
Levothyroxine tablets are used to replace the thryoxine that your
thyroid gland cannot produce and prevent the symptoms of
hypothyroidism. Before starting your treatment your doctor will carry
out a blood test to work out how much levothyroxine you need.

Do not take this medicine if you:
• are allergic to levothryoxine or to any of the other ingredients
(see section 6)
• suffer from an overactive thyroid gland that produces too much
thyroid hormone (thyrotoxicosis)
• have any condition that affects your adrenal glands (your doctor
will be able to advise you if you are not sure).
If any of these apply to you, do not take this medicine and go back to
your doctor to discuss your treatment.

Check with your doctor or pharmacist before taking these
tablets if you:
• have suffered with an under active thyroid gland for a long time
• suffer from heart problems including angina, coronary artery
disease or high blood pressure
• are being treated for diabetes. The dose of your anti-diabetic
medicine may need to be changed as levothyroxine can raise blood
sugar levels
• are over 50 years of age.
Blood tests:
Before you start taking levothyroxine your doctor will do a blood test to
see how much thyroxine your thyroid gland is making and what dose
of the medicine you will need. Once you start taking the medicine your
doctor will want you to have regular blood tests to see how well the
medicine is working.
Taking other medicines:
Many medicines affect the way levothyroxine works. The effects of
other drugs may also be affected by levothyroxine. You must tell your
doctor if you are taking or start taking any other medicines
including over the counter medicines, herbal remedies and vitamin
The following may affect the way that levothyroxine works:
• medicines for epilepsy such as carbamazepine, phenytoin,
primidone and barbiturates
• sertraline- used to treat depression and anxiety disorders
• antacids- used to treat indigestion
• medicines containing calcium salts
• cimetidine- used to reduce excess stomach acid
• proton pump inhibitors such as omeprazole, lansoprazole and
pantoprazole- used to reduce the amount of acid produced by the
• sucralfate- used to treat and prevent stomach and duodenal
• cholestyramine and colestipol- used to treat high level of fat in
the blood
• polystyrene sulphone resin- used to reduce high levels of
potassium in the blood
• medicines containing iron that are taken by mouth
• rifampicin- used to treat infections
• imatinib- used to treat certain types of cancer
• beta blockers such as atenolol and sotalol- used to treat high
blood pressure and heart problems
• oestrogen containing medicines for hormone replacement
therapy (HRT) and contraception (the ‘pill’)
• androgen containing medicines for male hormone replacement
• corticosteroids such as hydrocortisone and prednisoloneused to treat inflammation
• amiodarone- used to treat an irregular heart beat
The following may be affected by levothyroxine:
• anticoagulant medicines to prevent blood clots such as
• medicines to treat diabetes such as insulin and metformin
• tricyclic antidepressants such as amitriptyline, imipramine
and dosulepin
• medicines that stimulate the sympathetic nervous system such
as adrenaline (used to treat severe allergic reactions) or
phenylephrine (a decongestant found in many cold and flu
• digoxin- used to treat heart problems
• anti-inflammatory medicines such as phenylbutazone or aspirin
• propranolol- used to treat high blood pressure and heart
• ketamine- used as an anaesthetic. If you need to have an
operation, please tell your doctor or anaesthetist that you are
taking levothyroxine.
Pregnancy and breastfeeding:
If you are pregnant, particularly in the first three months of your
pregnancy, planning to become pregnant or are breastfeeding tell
your doctor or pharmacist before taking this medicine. Your doctor will
decide if you should continue treatment with levothyroxine whilst you
are pregnant.
Important information about some of the ingredients of
Levothyroxin Tablets:
This medicine also contains lactose, a sugar. If you have been told by
your doctor that you have an intolerance to some sugars, contact your
doctor before taking this medicine.

You may be taking this medicine for the rest of your life. Always take
levothyroxine tablets exactly as your doctor has told you. If you are
not sure, check with your doctor or pharmacist.
Your dose will be decided by your doctor and will depend on the results of your blood tests. The dose you should take will be on the label
attached by your pharmacist. Swallow the tablets with plenty of water.
You should usually take your tablets before breakfast or your first meal
of the day.
The usual starting dose is 50 - 100 micrograms every day. Your doctor
may increase the dose you take every 3 - 4 weeks by 50 micrograms
until your thyroxine levels are correct. Your final daily dose may be up
to 100 - 200 micrograms daily.
Patients over 50 years of age:
The usual starting dose will be no more than 50 micrograms every day.
The dose may then be increased by 50 micrograms every 3 - 4 weeks
until your thyroxine levels are correct. Your final daily dose will be
between 50 - 200 micrograms daily.
Patients over 50 years of age with heart problems:
The starting dose will be 25 micrograms every day or 50 micrograms
every other day. The dose may be increased by 25 micrograms every 4
weeks until your thyroxine levels are correct. Your final daily dose will
usually be between 50 - 200 micrograms daily.
Giving these tablets to children:
The dose for children depends on their age, weight and the condition
being treated. Your child will be monitored to make sure that they get
the right dose. You should give them their medicine at least half an
hour before breakfast or their first meal of the day. If necessary, the
tablets can be dissolved in 10 - 15ml of water and given with some
more liquid (5 - 10ml). The dissolved tablets should be taken straight
away. Do not keep the solution to give to your child later.
Congenital hypothyroidism in infants:

This is a condition where your baby has been born with a thyroid gland
that does not produce enough thyroxine. The starting dose is 10 - 15
micrograms/ kg bodyweight per day for the first three months. The
dose will then be adjusted depending on how your baby responds to
the treatment.
Acquired hypothyroidsim in children:

This is a condition where your child’s thyroid gland stops working
properly because it has been attacked by their immune system, e.g. in
children with an autoimmune disease or following a viral infection. The
starting dose is 12.5 - 50 micrograms per day. The dose will then be
increased every 2 - 4 weeks depending on how your child responds to
the medicine.
Juvenile myxoedema:

This is a condition where children and adolescents develop severe
hypothyroidism (produce very low levels of thyroid hormones). The

starting dose is 25 micrograms every day. The dose will then be
increased by 25 micrograms every 2 - 4 weeks until your child shows
mild symptoms of hyperthyroidism (a condition where the thyroid
gland produces too much thyroxine). The dose will then be reduced
If you take more Levothyroxine than you should:
If you (or someone else) swallow a lot of the tablets at the same time,
or you think a child may have swallowed some, contact your nearest
hospital casualty department or tell your doctor immediately. Signs of
an overdose may include: fever, chest pain (angina), racing or irregular
heartbeat, muscle cramps, headache, restlessness, flushing, sweating
and diarrhoea. These signs can take up to 5 days to appear. Take any
remaining tablets and this leaflet with you so that the medical staff
knows exactly what you have taken.
If you forget to take Levothyroxine:
If you forget to take a dose take it as soon as you remember unless
it is nearly time for your next dose. Do not take a double dose. If you
forget to give your child their dose, contact your doctor or pharmacist
for further advice.
Stopping the tablets:
These tablets are for long term use. You may need to take them for
the rest of your life. Do not stop taking the tablets unless your doctor
has told you to do so.

Some people may have side-effects when taking this medicine.
Stop taking the tablets and go to hospital at once if you have:
• A rare allergic reaction such as swelling of the face, tongue, lips
and throat, difficulty breathing, severe itching of your skin with
raised lumps, joint pain, sensitivity to the sun, general feeling of
being unwell. You may need urgent medical attention.

Some patients may experience a severe reaction to high levels
of thyroid hormone. This is called a “thyroid crisis” and you
should contact your doctor immediately if you have any of the
following symptoms:
• very high temperature; fast heart rate; irregular hearbeat; low
blood pressure; heart failure; jaundice; confusion; fits and coma.
Tell your doctor or pharmacist if any of the following side
effects continue, get worse or if you notice any other side
effects not listed.
Most of the side effects are similar to the symptoms of hyperthyroidism
(where the thyroid gland makes too much thyroxine) and are due to
your dose of the medicine being too high. They will usually disappear
after reducing the dose or stopping the tablets. However, you must
not change the dose or stop the tablets without talking to
your doctor first.
• headache
• flushing
• high temperature, sweating
• weight loss
• tremor, restlessness, excitability, difficulty sleeping (insomnia)
• increased pressure around the brain in children that is not caused
by a tumour or other diseases (benign intracranial hypertension)
• chest pain (angina), pounding, irregular or fast heartbeat
• diarrhoea, vomiting
• muscle cramps, muscle weakness
• deformity of the skull in infants caused by the early closure of
joints in the skull bone (craniostenosis)
• growth in children may slow or stop due to changes in bone
• irregular periods
• intolerance to heat
• temporary hair loss in children.
Reporting of side effects:
If you get any side effects, talk to your doctor, pharmacist or nurse.
This includes any possible side effects not listed in this leaflet. You can
also report side effects directly via the Yellow Card Scheme at
By reporting side effects you can help provide more information on the
safety of this medicine.

Do not store above 25oC. Store in the original package in order to
protect from light and moisture.
Do not use Levothyroxine tablets after the expiry date which is stated
on the box. The expiry date refers to the last day of that month.
Keep out of the sight and reach of children.
Medicines should not be disposed of via wastewater or household
waste. Ask your pharmacist how to dispose of medicines no longer
required. These measures will help protect the environment.

What Levothyroxine Tablets contain:
Each tablet contains 25 micrograms of levothyroxine sodium.
The other ingredients are sodium citrate, lactose monohydrate, maize
starch, acacia powder and magnesium stearate.
What Levothyroxine Tablets look like and contents of the
White, round tablets, scored on one side and engraved on the other
with ‘FW41’. They are packed in blister packs of 28.
Custom Pharmaceuticals Ltd., Tecore House, Conway Street, Hove,
East Sussex, BN3 3LW, UK
Procured from within the EU and repackaged by the Product Licence
Holder: Summer Healthcare Ltd., 4 Petre Road, Clayton Business Park,
Clayton-Le-Moors, Accrington BB5 5JB, UK.
PL: 33948/0045
Date of Leaflet: 4th July 2016

Expand view ⇕

Source: Medicines and Healthcare Products Regulatory Agency

Disclaimer: Every effort has been made to ensure that the information provided here is accurate, up-to-date and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. This information has been compiled for use by healthcare practitioners and consumers in the United States. The absence of a warning for a given drug or combination thereof in no way should be construed to indicate that the drug or combination is safe, effective or appropriate for any given patient. If you have questions about the substances you are taking, check with your doctor, nurse or pharmacist.