Consumer medicine information


Liothyronine sodium


Brand name


Active ingredient

Liothyronine sodium




Consumer medicine information (CMI) leaflet

Please read this leaflet carefully before you start using TERTROXIN.

What is in this leaflet

This leaflet answers some common questions about TERTROXIN. It does not contain all 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 risks of you taking TERTROXIN against the benefits he/she expects it will have for you.

Ask your doctor or pharmacist if you have any concerns about taking this medicine.

Keep this leaflet with the medicine. You may need to read it again.

What TERTROXIN is used for

TERTROXIN contains "liothyronine" which is a naturally occurring thyroid hormone.

It is used for treating:

  • disorders of thyroid deficiency or low thyroid levels in the body
  • coma or unconsciousness caused by severely low thyroid levels in the body
  • an overactive thyroid gland which occurs in thyrotoxicosis or Grave's Disease, together with other medicines
  • a low thyroid level after treatment of thyrotoxicosis.

Ask your doctor if you have any questions about why TERTROXIN has been prescribed for you. Your doctor may have prescribed TERTROXIN for another reason.

This medicine is only available with a doctor's prescription.

There is no evidence that TERTROXIN is addictive.

Before you use it

When you must not take it

Do not take TERTROXIN if:

  • you have an allergy to TERTROXIN or any of the ingredients listed at the end of this leaflet
  • you have angina
  • you have any other heart condition
  • you have an untreated adrenal gland condition

Do not take TERTROXIN if the packaging is torn or shows signs of tampering. Do not take TERTROXIN if the expiry date (EXP) printed on the pack has passed. If you take this medicine after the expiry date has passed, it may not work.

If you are not sure whether you should start taking TERTROXIN, contact your doctor.

Before you start to take it

Tell your doctor if you have allergies to any other foods, medicines, preservatives or dyes.

Tell your doctor if:

  1. you are pregnant or intend to become pregnant.
    If there is a need to consider TERTROXIN during your pregnancy, your doctor will discuss with you the benefits and risks of using it.
  2. you are breast-feeding or plan to breast-feed.
    TERTROXIN passes into breast milk and therefore there is a possibility that the breast-fed baby may be affected.
    Your doctor will discuss the risks and benefits of taking TERTROXIN when breast-feeding.
  3. you have or have had any medical conditions, especially the following:
  • diabetes
  • adrenal gland problems

If you have not told your doctor about any of the above, tell him/her before you start taking TERTROXIN.

Taking other medicines

Tell your doctor if you are taking any other medicines, including any that you buy without a prescription from your pharmacy, supermarket or health food shop.

Some medicines and TERTROXIN may interfere with each other. These include:

  • medicines used to treat blood clots
  • phenytoin and carbamazepine, medicines used to treat fitting or epilepsy
  • digoxin, a medicine used for certain heart conditions
  • cholestyramine, a medicine used to reduce cholesterol levels
  • tricyclic antidepressants
  • oral contraceptives or the pill
  • ketamine, an anaesthetic
  • insulin or tablets used to treat diabetes.

These medicines may be affected by TERTROXIN, or may affect how well it works. You may need to take different amounts of your medicine, or you may need to take different medicines. Your doctor will advise you.

Your doctor and pharmacist have more information on medicines to be careful with or avoid while taking TERTROXIN.

How to take TERTROXIN

Follow all directions given to you by your doctor and pharmacist carefully. These directions may differ from the information contained in this leaflet.

If you do not understand the instructions on the bottle, ask your doctor or pharmacist for help.

How much to take

In adults, the usual dose for low thyroid levels is one tablet taken two or three times a day.

In children, the usual dose is half a tablet taken once to three times daily.

In both adults and children the dose will depend on the condition being treated and the level of thyroid hormone in the body.

How to take it

Swallow TERTROXIN with a glass of water.

When to take it

Take TERTROXIN at about the same time each day. Taking your tablets at the same time each day will have the best effect. It will also help you remember when to take the tablets.

It does not matter if you take TERTROXIN before or after food.

How long to take it

TERTROXIN helps to control your thyroid problem. Therefore, your medicine must be taken every day. Continue taking TERTROXIN for as long as your doctor prescribes it. In some conditions you will take this medicine for the rest of your life.

If you forget to take it

If it is almost time for your next dose, skip the dose you missed and take your next dose when you are meant to. Otherwise, take it as soon as you remember and then go back to taking your tablets as you would normally.

Do not take a double dose to make up for the dose that you missed.

If you have trouble remembering to take your medicine, ask your pharmacist for some hints.

If you take too much (overdose)

Immediately telephone your doctor or Poisons Information Centre (telephone 13 11 26) or go to casualty at your nearest hospital, if you think that you or anyone else may have taken too much TERTROXIN. Do this even if there are no signs of discomfort or poisoning. You may need urgent medical attention.

If you take too much TERTROXIN you may feel:

  • irritable
  • nervous
  • have a headache
  • an abnormal heart beat
  • muscle cramps
  • flushing or skin redness
  • diarrhoea
  • heart conditions may become worse

While you are using TERTROXIN

Things you must do

If you are about to be started on any new medicine tell your doctor and pharmacist that you are taking TERTROXIN.

Tell all of the doctors, dentists, and pharmacists that are treating you that you are taking TERTROXIN.

Be sure to keep all of your doctor's and blood test appointments so that your progress can be checked.

If you are being treated for diabetes, make sure you check your blood sugar level regularly and report any problems to your doctor. TERTROXIN may change how well your diabetes is controlled. Your doses of diabetic medicines, including insulin, may need to change.

If you are taking an anticoagulant (eg. warfarin), make sure you have your blood tested regularly and report any problems to your doctor. TERTROXIN may change how well anticoagulants work. Your dose of the anticoagulant may need to change.

Things you must not do

Do not give TERTROXIN to anyone else, even if they have the same condition as you.

Do not use TERTROXIN to treat any other complaint unless your doctor tells you to.

Side effects

Check with your doctor as soon as possible if you have any problems while taking TERTROXIN, even if you do not think the problems are connected with the medicine or are not listed in this leaflet.

Like other medicines, TERTROXIN can cause some side effects. If they occur, most are likely to be minor and temporary. However, some may be serious and need medical attention.

Tell your doctor if you notice any of the following and they worry you:

  • headache
  • muscle cramps
  • diarrhoea
  • restlessness
  • excitability
  • flushing or redness of skin
  • sweating
  • muscle weakness

These side effects are usually mild.

Tell your doctor immediately if you notice any of the following:

  • palpitations
  • heart pain
  • changes in heart beat
  • excessive loss of weight

These are serious side effects. You may need urgent medical attention. Serious side effects are rare.

Tell your doctor if you notice anything else that is making you feel unwell.

Other side effects not listed above may also occur in some patients.

Do not be alarmed by this list of possible side effects. You may not experience any of them.

After using TERTROXIN


Keep your tablets in the bottle until it is time to take them. If you take the tablets out of the bottle they will not keep well.

Keep the tablets in a cool dry place where the temperature stays below 25°C.

Do not store TERTROXIN or any other medicine in the bathroom or near a sink. Do not leave it in the car or on window sills. Heat and dampness can destroy some medicines.

Keep it where children cannot reach it. A locked cupboard at least one-and-a-half metres above the ground is a good place to store medicines.


If your doctor tells you to stop taking TERTROXIN or the tablets have passed their expiry date, ask your pharmacist what to do with any that are left over.

Product description

What it looks like

TERTROXIN are white uncoated tablets, plain in one side and with a break line on the other side.


TERTROXIN contains 20 micrograms of liothyronine sodium as the active ingredient.

The other ingredients in TERTROXIN are:

  • lactose
  • maize starch
  • acacia
  • sodium chloride
  • magnesium stearate

TERTROXIN does not contain gluten, sucrose, tartrazine or any other azo dyes.


TETROXIN is distributed in Australia by:

Aspen Pharma Pty Ltd
34-36 Chandos Street
St Leonards NSW 2065

The Australian Registration number for TERTROXIN is:
AUST R 12520.

This revised in January 2012.

Published by MIMS May 2016


Brand name


Active ingredient

Liothyronine sodium




1 Name of Medicine

Liothyronine sodium.

2 Qualitative and Quantitative Composition

Each tablet contains 20 microgram liothyronine sodium. The excipients include sodium chloride and lactose. For the full list of excipients, see Section 6.1 List of Excipients.

3 Pharmaceutical Form

Tablet - white, uncoated, plain on one side and with a break line on the other.

4 Clinical Particulars

4.1 Therapeutic Indications

Tertroxin is indicated in the treatment of: coma due to myxoedema; management of severe thyroid deficiency; hypothyroid states arising in treatment of thyrotoxicosis.
Tertroxin may be preferred for treating severe and acute hypothyroid states because of its rapid and more potent effect, but thyroxine sodium is normally the drug of choice for routine replacement therapy.
Tertroxin can also be used therapeutically in the treatment of thyrotoxicosis as an adjunct to carbimazole in order to prevent subclinical hypothyroidism developing during treatment.

4.2 Dose and Method of Administration

In myxoedema, unless an immediate effect is needed, it is best to begin with small doses, 10-20 microgram every 8 hours, increasing by steps, if necessary, to a total daily dosage of 60 microgram administered in divided doses. This dosage usually suffices for maintenance, but for continuous maintenance it is generally considered that thyroxine is desirable, for its disadvantages in treating manifestations of hypometabolism are advantages where therapy has to be continuous throughout life.
Treatment of myxoedema coma should be initiated under specialist supervision. Sixty microgram may be given by stomach tube, then 20 microgram every 8 hours, although it is more usual to start treatment with intravenous liothyronine.
As therapy for thyrotoxicosis, with carbimazole: in adults 20 microgram of liothyronine every 8 hours.
For children and elderly patients it is suggested that the initial dosage should be 5 microgram daily. In children, the daily dosage of Tertroxin is 10-40 microgram, depending on age, condition to be treated and response.
The dose of Tertroxin should be divided and given two or three times daily.
If doses of less than 10 microgram of Tertroxin are required, tablets may be crushed and triturated with lactose for administration as a powder. However, it must be borne in mind that because of the very low amounts of active drug involved, uniform dispersion of the drug in the final powder cannot be guaranteed. In addition, the effect of trituration on bioavailability will be unknown.

4.3 Contraindications

Patients with angina of effort or cardiovascular disorders.
Hypersensitivity to liothyronine sodium.
Patients with untreated adrenal cortical insufficiency.
Patients with untreated hyperthyroidism.

4.4 Special Warnings and Precautions for Use

Endocrine disorders.

Liothyronine should be used with caution in patients with concomitant endocrine diseases such as diabetes mellitus or adrenocortical insufficiency.

Myxoedemic coma.

Glucocorticoids should be used in conjunction with thyroid hormones in the management of myxoedemic coma.

Concurrent use with oral anticoagulants.

See Section 4.5 Interactions with Other Medicines and Other Forms of Interactions.
Liothyronine should be used with caution in patients with cardiovascular disorders, especially those with angina and the elderly.
In severe prolonged hypothyroidism, the decreased level of adrenocortical activity may require supplementation with adrenocorticotrophic hormones. Adrenal deficiency must be corrected in patients with hypopituitarism prior to commencement of liothyronine therapy.
The use of thyroid hormones has been rarely reported to precipitate a hyperthyroid state.


It is important to remind patients of increased insulin requirements if they are prescribed Tertroxin.

Patients on anticoagulants.

There may be an altered response to anticoagulants requiring an initial increased frequency of monitoring of prothrombin times.
Patients should also be reminded of the importance of reporting to the doctor any chest pain, palpitations or excessive sweating.
Liothyronine should not be used in the management of obesity in euthyroid patients because doses within the range of daily hormonal requirements are ineffective and larger doses may produce serious or life threatening adverse effects.

Use in the elderly.

Special care is needed in the elderly who may exhibit increased sensitivity to the effects of thyroid replacement therapy. See Section 4.2 Dose and Method of Administration.

Paediatric use.


Craniosynotosis may occur in infants given high doses of thyroid hormones.


A partial loss of hair may occur in children (pediatric patients) that are administered with thyroid hormones in the first few months of thyroid therapy; however, this effect is usually a transient phenomenon and later recovery is usually the rule.
See Section 4.2 Dose and Method of Administration.

Effects on laboratory tests.

Laboratory tests: Periodic assessment of thyroid status should be conducted by means of appropriate laboratory tests and clinical observation.

4.5 Interactions with Other Medicines and Other Forms of Interactions

Liothyronine sodium therapy may potentiate the action of anticoagulants by increasing the catabolism of vitamin K dependent clotting factors.
Initiation or discontinuation of anticonvulsant therapy may alter liothyronine dose requirements.
If coadministered with cardiac glycosides, adjustment of the dosage of cardiac glycoside may be necessary. Thyroxine may potentiate digitalis toxicity. The increased metabolic rate following liothyronine therapy may increase digitalis requirements.
Cholestyramine given concurrently reduces gastrointestinal absorption of liothyronine by binding liothyronine within the gut lumen.
Liothyronine increases receptor sensitivity to catecholamines, thus potentially increasing the risk of cardiac arrythmias in patients receiving tricyclic antidepressants.
A number of drugs may affect thyroid function tests and this should be borne in mind when monitoring patients on liothyronine therapy.
Coadministration of oral contraceptives may result in an increased dosage requirement of thyroid therapy as oestrogens increase levels of thyroid binding globulin.
Ketamine may cause hypertension and tachycardia when administered to patients receiving thyroid replacement therapy.
Patient requirements of insulin or oral hypoglycaemics may increase in patients receiving therapy with liothyronine.
Phenytoin levels may be increased by liothyronine. Anticonvulsants such as carbamazepine and phenytoin enhance the metabolism of thyroid hormones and may displace them from plasma proteins.

4.6 Fertility, Pregnancy and Lactation

Effects on fertility.

No data available.
(Category A)
There is, however, very limited placental transfer of thyroid hormones.
Liothyronine is excreted in breast milk.

4.7 Effects on Ability to Drive and Use Machines

The effects of this medicine on a person's ability to drive and use machines were not assessed as part of its registration.

4.8 Adverse Effects (Undesirable Effects)

Reporting suspected adverse effects.

Reporting suspected adverse reactions after registration of the medicinal product is important. It allows continued monitoring of the benefit-risk balance of the medicinal product. Healthcare professionals are asked to report any suspected adverse reactions at
Tertroxin is capable of producing the same side effects and can show the same symptoms of overdosage as the thyroid hormone, but in practice (except in myxoedema) these symptoms are fairly uncommon and they disappear rapidly when treatment is stopped or the dosage is reduced. The usual symptoms are palpitation and headache. Also reported are anginal pain, cardiac arrhythmias, cramps in skeletal muscle, tachycardia, diarrhoea, restlessness, excitability, flushing, sweating, excessive loss of weight and muscle weakness.
The euthyroid patient shows much greater tolerance to the thyroid hormone than the thyroprivic case. It has already been mentioned that in myxoedema, side effects from the rapid re-establishment of the normal state may occur; these, too, are quickly controlled by reducing the dosage.

4.9 Overdose

Signs and symptoms include headache, irritability, nervousness, tachycardia, cardiac arrhythmias, skeletal muscle cramps, flushing, diarrhoea and excessive loss of weight. Congestive heart failure may be induced or aggravated.
Dosage should be reduced or therapy temporarily discontinued if signs and symptoms of overdose appear. Treatment may be reinstated at a lower dosage. In normal individuals, normal hypothalamic pituitary thyroid axis function is restored in 6 to 8 weeks after thyroid suppression.
Treatment of acute massive thyroid hormone overdosage is aimed at reducing gastrointestinal absorption of the drugs and counteracting central and peripheral effects, mainly those of increased sympathetic activity. Vomiting may be induced initially, if further gastrointestinal absorption can be reasonably prevented and barring contraindications such as coma, convulsions or loss of the gagging reflex. Treatment is symptomatic and supportive. Oxygen may be administered and ventilation maintained. Cardiac glycosides may be indicated if congestive heart failure develops. Measures to control fever, hypoglycemia or fluid loss should be instituted if needed.
The patient may present in shock. Symptoms may resemble thyroid storm. Treatment is symptomatic, tachycardia has been controlled in an adult by 40 mg doses of propranolol given every six hours. Antiadrenergic agents, particularly propanolol, have been used advantageously in the treatment of increased sympathetic activity. Propranolol may be administered intravenously at a dosage of 1 to 3 mg over a 10 minute period, or orally 80 to 160 mg/day, especially when no contraindications exist for its use.
Congestive heart failure may require the administration of cardiac glycosides. Supportive measures may include measures such as the management of fever, hypoglycaemia or fluid loss if necessary, as per the above.
For information on the management of overdose, contact the Poisons Information Centre on 13 11 26 (Australia).

5 Pharmacological Properties

5.1 Pharmacodynamic Properties

Mechanism of action.

The principal pharmacological effect of exogenous thyroid hormones is to increase the metabolic rate of body tissues.
The biological action of liothyronine sodium is qualitatively similar to that of thyroxine but the effect develops in a few hours and disappears within 24-48 hours of stopping treatment.

Clinical trials.

No data available.

5.2 Pharmacokinetic Properties


Liothyronine is readily and almost completely absorbed from the gastrointestinal tract following oral administration.


In the circulation, liothyronine is principally bound to thyroxine binding globulin (TBG). The plasma half-life of liothyronine in euthyroidism is approximately 1-2 days; it is prolonged in hypothyroidism and reduced in hyperthyroidism.


Liothyronine is metabolised by deiodination to inactive di-iodothyronine and mono-iodothyronine. Further metabolites result from deamination and decarboxylation to tiratricol (triac).

5.3 Preclinical Safety Data


No data available.


No data available.

6 Pharmaceutical Particulars

6.1 List of Excipients

Acacia, magnesium stearate, maize starch, sodium chloride, lactose.

6.2 Incompatibilities

Incompatibilities were either not assessed or not identified as part of the registration of this medicine.

6.3 Shelf Life

In Australia, information on the shelf life can be found on the public summary of the Australian Register of Therapeutic Goods (ARTG). The expiry date can be found on the packaging.

6.4 Special Precautions for Storage

Store below 25°C. Protect from light.

6.5 Nature and Contents of Container

Supplied in a HDPE bottle with child resistant closure containing 100 tablets.

6.6 Special Precautions for Disposal

In Australia, any unused medicine or waste material should be disposed of by taking to your local pharmacy.

6.7 Physicochemical Properties

Liothyronine (L triiodothyronine) sodium is a naturally occurring thyroid hormone. It is the sodium salt of the L-isomer of 3,3',5 triiodothyronine. It is a white or slightly coloured powder, practically insoluble in water and slightly soluble in alcohol. Molecular formula: C15H11I3NNaO4, Molecular Weight 673.

Chemical structure.

CAS number.


7 Medicine Schedule (Poisons Standard)


Summary Table of Changes