LIOTHYRONINE SODIUM

Posology 5 to 20 micrograms given by slow intravenous injection and repeated at intervals of 12 hours or less if required. The minimal interval between dosing is 4 hours. An initial dose of 50 micrograms intravenously is used by some physicians, followed by further intravenous injections of 25 micrograms every 8 hours until improvement occurs.

The dosage may then be reduced to 25 micrograms intravenously twice daily.

Method of Administration:

Usually given by intravenous injection, as the alkalinity of the solution may cause irritation of the tissues if given by deep intramuscular injection. The solution is prepared by adding 1 or 2ml water of injection to the ampoule and shaking gently until the solution has dissolved.

Side-effects are usually indicative of excessive dosage. The undesirable effects are listed below by organ class and the following frequency convention: Rare (≥1/10,000 to <1/1,000); Not known (cannot be estimated from the available data) System organ class Frequency Undesirable effects Immune system disorders Not Known Hypersensitivity reactions including rash, pruritus and oedema.

Metabolism and nutrition disorders Not Known Weight loss Nervous system disorders Not Known Tremor, restlessness, excitability, insomnia. Cardiac disorders Not Known Anginal pain, cardiac arrhythmias, palpitations, tachycardia. Gastrointestinal disorders Not Known Diarrhoea, vomiting Musculoskeletal and connective tissue disorder Not Known Muscle cramps, muscle weakness.

Reproductive system and breast disorders Not Known Menstrual irregularities (relevant to maintenance therapy) General disorders and administration site conditions Not Known Headache, flushing, fever and sweating. Paediatric populations: • Benign intracranial hypertension in children (Rare) • Heat intolerance and transient hair loss in children (Not Known) • Craniostenosis in infants and premature closure of epiphysis in children (Not Known) Reporting of suspected adverse reactions: Reporting suspected adverse reactions after authorisation of the medicinal product is important.

It allows continued monitoring of the benefit/risk balance of the medicinal product. uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store.

Liothyronine must be given with extreme caution in myxoedema coma because too large a dose can precipitate heart failure, especially in the elderly patients and those with ischaemic heart disease. ECG monitoring can give a useful indication of impending ischemia, however, changes in ST segment can be confused with similar changes occurring in hypothyroidism.

Liothyronine should be used with caution in patients with long-standing hypothyroidism, cardiovascular disorders, including angina, coronary artery disease, hypertension, and in the elderly, who have a greater likelihood of occult cardiac disease.

In severe and prolonged hypothyroidism, there may be decreased adrenocortical activity. When thyroid replacement therapy is started, metabolism is raised at a greater rate than adrenocortical activity, and this can result in adrenocortical insufficiency.

This insufficiency may require supplemental adrenocortical steroids. Thyroid replacement therapy may cause an increase in the dosage requirement of insulin or other anti-diabetic treatment. Care is needed in patients with diabetes mellitus and diabetes insipidus.

Interferences with laboratory test:

Biotin may interfere with thyroid immunoassays that are based on a biotin/streptavidin interaction, leading to either falsely decreased or falsely increased test results. The risk of interference increases with higher doses of biotin.

When interpreting results of laboratory tests, possible biotin interference has to be taken into consideration, especially if a lack of coherence with the clinical presentation is observed. For patients taking biotin-containing products, laboratory personnel should be informed when a thyroid function test is requested.

Alternative tests not susceptible to biotin interference should be used, if available. 5).

1 Liothyronine sodium is contraindicated in patients with cardiovascular disorders or angina of effort and thyrotoxicosis.