SUMMARY CMI

TERTROXIN tablets

Consumer Medicine Information (CMI) summary

The full CMI on the next page has more details. If you are worried about using this medicine, speak to your doctor or pharmacist.

1. Why am I using TERTROXIN?

TERTROXIN contains the active ingredient liothyronine sodium. It is used to treat 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 or a low thyroid level after treatment of thyrotoxicosis.

For more information, see Section 1. Why am I using TERTROXIN? in the full CMI.

2. What should I know before I use TERTROXIN?

Do not use if you have ever had an allergic reaction to liothyronine sodium or any of the ingredients listed at the end of the CMI.

Talk to your doctor if you have any other medical conditions, take any other medicines, or are pregnant, plan to become pregnant, are breastfeeding or plan to breastfeed.

For more information, see Section 2. What should I know before I use TERTROXIN? in the full CMI.

3. What if I am taking other medicines?

A list of these medicines is in Section 3. What if I am taking other medicines? in the full CMI.

4. How do I use TERTROXIN?

• In adults, the usual starting dose 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.
• Swallow the tablets whole with a glass of water.
• Take the tablets at the same time each day. It does not matter if you take it before or after food.
• Continue taking TERTROXIN as long as your doctor recommends it.

More instructions can be found in Section 4. How do I use TERTROXIN? in the full CMI.

5. What should I know while using TERTROXIN?

For more information, see Section 5. What should I know while using TERTROXIN? in the full CMI.

6. Are there any side effects?

All medicines can have side effects. If they do occur, they are usually minor and temporary. Do not be alarmed by this list. You may not experience any of them.

It is important to be aware of potential side effects so that you can identify any symptoms if they occur.

For more information, including what to do if you have any side effects, see Section 6. Are there any side effects? in the full CMI.

FULL CMI

TERTROXIN tablets

Active ingredient: liothyronine sodium

Consumer Medicine Information (CMI)

This leaflet provides important information about using TERTROXIN.

You should also speak to your doctor or pharmacist if you would like further information or if you have any concerns or questions about using TERTROXIN.

Where to find information in this leaflet:

1. Why am I using TERTROXIN?
2. What should I know before I use TERTROXIN?
3. What if I am taking other medicines?
4. How do I use TERTROXIN?
5. What should I know while using TERTROXIN?
6. Are there any side effects?
7. Product details

1. Why am I using TERTROXIN?

TERTROXIN contains the active ingredient liothyronine sodium, a thyroid hormone.

TERTROXIN is used to treat:

1. disorders of thyroid deficiency or low thyroid levels in the body
2. coma or unconsciousness caused by severely low thyroid levels in the body
3. an overactive thyroid gland which occurs in thyrotoxicosis or Grave's disease, together with other medicines
4. 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 purpose.

There is no evidence that TERTOXIN is addictive.

2. What should I know before I use TERTROXIN?

Warnings

Do not use TERTROXIN if:

• you are allergic to liothyronine or any of the ingredients listed at the end of this leaflet.
  Some symptoms of an allergic reaction may include shortness of breath, wheezing or difficulty in breathing; swelling of the face, lips, tongue, or any other parts of the body; rash, itching or hives on the skin.
• you have angina
• you have any other heart condition
• you have an untreated adrenal gland condition
• the expiry date printed on the pack has passed
• the packaging is torn or shows signs of tampering.

Check with your doctor if you:

• have had any allergy to any other medicines, or any other substances, such as foods, preservatives, or dyes.
• have or have had any other medical conditions or health problems including:
  - adrenal gland problem
  - diabetes.

During treatment, you may be at risk of developing certain side effects. It is important you understand these risks and how to monitor for them. See additional information under Section 6. Are there any side effects?

Pregnancy and breastfeeding

Check with your doctor if 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.

Check with your doctor if you are breastfeeding or intend to breastfeed.

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. What if I am taking other medicines?

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

Some of these medicines may interfere with TERTROXIN. 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.

Check with your doctor or pharmacist if you are not sure about what medicines, vitamins or supplements you are taking and if these affect TERTROXIN tablets.

4. How do I use TERTROXIN?

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.

Carefully follow the dosage instructions. Do not change your dose unless your doctor tells you to do so.

Talk to your doctor if you have any further questions.

How long to take it for

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.

How to take it

Swallow the tablets 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.

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 it as you would normally.

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

If you take too much

If you think that you have used too much TERTROXIN, you may need urgent medical attention.

You should immediately:

• phone the Poisons Information Centre
  (by calling 13 11 26), or
• contact your doctor, or
• go to the Emergency Department at your nearest hospital.

You should do this even if there are no signs of discomfort or poisoning.

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.

5. What should I know while using TERTROXIN?

Things you should do

If you are about to start taking any new medicines, remind your doctor and pharmacist that you are taking TERTROXIN.

Tell any other doctors, dentists and pharmacists who are treating you that you are using TERTROXIN.

Visit your doctor regularly.

Your doctor needs to check your progress.

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 (e.g. 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 should not do

Do not give this medicine to anyone else, even if their symptoms seem similar to yours.

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

Looking after your medicine

Keep TERTROXIN tablets in the bottle until it is time to take them.

If you take the tablets out of the bottle they may not keep as well.

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

Do not store this medicine:

• in the bathroom or near a sink, or
• in the car or on window sills.

Heat and dampness can destroy some medicines.

Keep it where young children cannot reach it.

Getting rid of any unwanted medicine

If you no longer need to use this medicine or it is out of date, take it to any pharmacy for safe disposal.

6. Are there any side effects?

All medicines can have side effects. If you do experience any side effects, most of them are minor and temporary. However, some side effects may need medical attention.

Less serious side effects

Serious side effects

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

Other side effects not listed here may occur in some people.

Reporting side effects

After you have received medical advice for any side effects you experience, you can report side effects to the Therapeutic Goods Administration online at www.tga.gov.au/reporting-problems. By reporting side effects, you can help provide more information on the safety of this medicine.

Always make sure you speak to your doctor before you decide to stop taking any of your medicines.

7. Product details

TERTROXIN tablets are only available with a doctor's prescription.

What TERTROXIN tablets contain

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

Do not take this medicine if you are allergic to any of these ingredients.

What TERTROXIN looks like

TERTROXIN tablets are white, biconvex, uncoated tablets plain on one side and with a break line on the other side. Available in plastic bottles of 100 tablets.

Australian Registration number: AUST R 12520

Who distributes TERTROXIN?

Aspen Pharmacare Australia Pty Ltd
34-36 Chandos St
St Leonards NSW 2065
Australia

This leaflet was revised in May 2025.

Published by MIMS August 2025

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.

Myxoedemic coma.

Concurrent use with oral anticoagulants.

Diabetics.

Patients on anticoagulants.

Use in the elderly.

Paediatric use.

Infants.

Children.

Effects on laboratory tests.

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.

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.

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.

Clinical trials.

5.2 Pharmacokinetic Properties

Absorption.

Distribution.

Metabolism.

5.3 Preclinical Safety Data

Genotoxicity.

Carcinogenicity.

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)

S4.

Summary Table of Changes