LEVOTHYROXINE SERB

Posology • Perform thyroid function test (T3, T4 and TSH levels) before treatment with levothyroxine injection. The starting and maintenance doses depend on the degree of hypothyroidism, the patient’s age and individual tolerance. • Daily administration of levothyroxine injection should be continued until the patient is able to tolerate oral therapy.

75 1 Adults Myxoedema coma: A loading dose of 200 to 500 micrograms is recommended. Due to an increased risk of serious cardiovascular events or death, this loading dose must not exceed 500 micrograms. 2 micrograms per kilogram body weight (75-90 micrograms).

Hypothyroidism where oral therapy is not feasible:

Oral to iv conversion: Gastrointestinal absorption of oral levothyroxine tablet is approximately 70%–80% in healthy fasting adults, therefore, parenteral levothyroxine should be administered at an initial dose that corresponds to 70-80% of the patient’s oral dose.

• Complete hormone replacement therapy in adults requires 100 to 150 micrograms as a single daily dose, on average. This dosage will be established gradually and with caution: start with 25 micrograms per day, then increase the daily dose by 25 micrograms at weekly intervals.

• Once the dosage has been stable for a long enough period (4-6 weeks), repeat testing of thyroid hormones levels. Monitor T3 and T4 levels to check that there is no overdose and monitor normalisation of TSH levels in the event of peripheral hypothyroidism.

4), for whom treatment should be initiated at lower doses, and follow more gradual increments. A maintenance dose lower than that required to normalise TSH levels may be considered. Patients with renal / hepatic insufficiency Experience in patients with renal and/or hepatic insufficiency is limited.

Paediatric population Myxoedema coma:

Experience in children treated for myxoedema coma is very limited. Use of parenteral levothyroxine 10 micrograms/kg/day in 3 divided doses for 24 hours as loading dose followed by 3 micrograms/kg/day as maintenance therapy has been reported in published case reports.

Dose should be adjusted based on clinical and laboratory findings.

Hypothyroidism where oral therapy is not feasible:

The daily replacement dose of intravenous levothyroxine should be no more than 75% of the oral dose. In all cases, the dose should be adjusted on the basis of the needs of each individual. Method of administration Intravenous injection.

Intramuscular injection possible. 9%) solution for injection solution to achieve a concentration of the diluted solution of 2 micrograms/ml.

If the patient does not tolerate the dosage given or overdosage occurs, the typical symptoms of hyperthyroidism may occur, especially if the dose is increased too rapidly at the start of treatment. In these cases, the daily dosage should be reduced, or the medication should be stopped for several days.

Treatment may be restarted with cautious dose adjustment once the side effects have disappeared. Hypersensitivity reactions to levothyroxine or other ingredients in Levothyroxine SERB 200 micrograms/ml solution for injection/infusion include angioedema, rash, urticaria, wheezing.

Adverse reactions are classified into the following categories in order of frequency: Very common (≥1/10); common (≥1/100 to <1/10); uncommon (≥1/1,000 to <1/100); rare (≥1/10,000 to <1/1,000); very rare (<1/10,000), not known (cannot be estimated from the available data).

4) Not known Gastrointestinal disorders Diarrhoea, vomiting and nausea Not known Skin and subcutaneous Angioedema, rash, urticaria, Not known disorders sweating Musculoskeletal and connective tissue disorders Muscle weakness and cramps, osteoporosis at suppressive doses of levothyroxine, especially in postmenopausal women, mainly when treated for a long period.

Not known Reproductive system and breast disorders menstrual irregularities Not known General disorder and administration site conditions Heat intolerance, fever. Not known Investigations Weight loss 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.

Before starting a thyroid hormone therapy, the following diseases or conditions should be excluded or treated: - Coronary heart disease, - angina pectoris, - hypertension, - pituitary and/or adrenal insufficiency, - thyroid autonomy.

It is essential that even mild, drug-induced hyperthyroidism be avoided in patients with coronary heart disease, heart failure, tachyarrhythmias, myocarditis of non-acute course, chronic hypothyroidism or in patients who have already suffered a myocardial infarction.

2). Thyroid hormones should not be given for weight reduction. In euthyroid patients, treatment with levothyroxine does not cause weight reduction. Substantial doses may cause serious or even life-threatening undesirable effects, particularly in combination with certain substances for weight reduction, and especially with sympathomimetic amines.

If a switch to another levothyroxine-containing product is required, there is a need to undertake a close monitoring including clinical and laboratory monitoring during the transition period due to a potential risk of thyroid imbalance.

In some patients, dose adjustment may be necessary. 2). Patients with cardiovascular disorders or with a history of cardiovascular disorders Levothyroxine by the intravenous/intramuscular route can be associated with cardiac toxicity (in particular arrhythmia, tachycardia, myocardial ischaemia and myocardial infarction or exacerbation of congestive heart failure and death) in patients with underlying cardiovascular disease (in particular coronary disorders, arrhythmias, hypertension, decompensated heart failure).

Due to the increased prevalence of cardiovascular diseases in the elderly, caution is required when administering levothyroxine solution for injection/infusion in elderly patients or those with known cardiac risk factors. 2). Regular and careful monitoring of cardiac conditions is necessary at treatment initiation and throughout treatment.

Patients with adrenal insufficiency In case adrenocortical dysfunction occurs concomitantly with myxoedema coma, patients should be treated with glucocorticoids before starting levothyroxine. Low birth weight preterm neonates Haemodynamic parameters should be monitored when levothyroxine therapy is initiated in very low birth weight preterm neonates as circulatory collapse may occur due to the immature adrenal function.

The proposed dose of Levothyroxine SERB may be a significant addition to the circulating blood volume of preterm infants. This should be taken into account when calculating daily fluid requirements. Diabetes The addition of levothyroxine to an anti-diabetic treatment or insulin therapy can lead to an increase in insulin or anti-diabetic drug requirements.

5). Patients with a history of epilepsy Due to the risk of seizures in patients with a history of epilepsy, monitoring of these patients is recommended throughout treatment with levothyroxine. Hypersensitivity Hypersensitivity reactions (including angioedema), sometimes serious, have been reported with Levothyroxine SERB, 200 micrograms/ml solution for injection/infusion use.

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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) This medicine contains less than 1 mmol sodium (23 mg) per ampoule, that is to say essentially ‘sodium-free’.

1. g. acute myocardial infarction, acute myocarditis, acute pancarditis). 4). Untreated hyperthyroidism. Untreated pituitary insufficiency (when leading to adrenal insufficiency requiring treatment). 6).