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The format of this leaflet was determined by the Ministry of Health and its
content was checked and approved by it on Dec2013
Summary of Product Characteristics
NAME OF THE MEDICINAL PRODUCT
Eltroxin® Tablets 50mcg
Eltroxin® Tablets 100mcg
2.
QUALITATIVE AND QUANTITATIVE COMPOSITION
Eltroxin Tablet containing 50 mcg (0.05mg) or 100 mcg (0.1mg) anhydrous thyroxine sodium respectively, which is the monosodium salt of the levorotary isomer of thyroxine 3. PHARMACEUTICAL
4. CLINICAL
PARTICULARS

4.1 Therapeutic
indications
Treatment of hypothyroidism, cretinism and juvenile myxoedema Posology and method of administration
If the dose of thyroxine is increased too rapidly, symptoms such as diarrhoea, nervousness,
rapid pulse, insomnia, tremors and sometimes anginal pain where there is latent myocardial
ischaemia, may occur, and the dosage must be reduced or withheld for a day or two, then
restarted at a lower level. A pre-therapy ECG is valuable, as changes induced by
hypothyroidism may be confused with ECG evidence of ischaemia.
Due to a lack of data it is not appropriate to crush thyroxine tablets and thyroxine tablets
without a score-line must not be halved.
Thyroxine tablets should preferably be taken on an empty stomach.
Missed dosage
If a scheduled daily dose is missed, the dose should be taken as soon as the patient
remembers, unless it is almost time for the patient’s next dose. Two doses should not be
taken together.
Populations

 Adults
Initially 50 to 100 micrograms daily and adjust at 4 to 6 week intervals by 50 micrograms until
attainment of clinical and biochemical euthyroidism. This may require doses of 100 to 200
micrograms daily.
With patients aged over 50 years, it is not advisable to exceed 50 micrograms a day initially. Where there is cardiac disease, 50 micrograms on alternate days is more suitable. In this condition the daily dosage may be increased by 50 micrograms on alternate days, at intervals of approximately 4 weeks.
 Children
In congenital hypothyroidism and juvenile myxoedema, the largest dose consistent with
freedom from toxic effects should be given. The dosage is guided by clinical response, growth
assessment and appropriate thyroid function tests – clinically normal pulse rate and absence
of diarrhoea or constipation are the most useful indicators. Thyrotrophin levels may remain
elevated during the first year of life in children with neonatal hypothyroidism due to resetting
of the hypothalamic-pituitary axis.
For infants with congenital hypothyroidism a suitable starting dose is 50 micrograms thyroxine
sodium on alternate days, with increments of 50 mcg on alternate days at intervals of every
two to four weeks until optimal response is achieved. The same dosing regimen applies to
juvenile myxoedema, except that the starting dose for children older than one year may be
2.5 to 5 micrograms/kg/day. The calculated daily dose equivalent should be rounded to the
nearest 25 micrograms to determine the actual prescribed dose.

4.3 Contraindications
 Hypersensitivity to any component of the preparation.  Untreated adrenal insufficiency, untreated pituitary insufficiency, and thyrotoxicosis.  Treatment with Eltroxin must not be initiated in acute myocardial infarction, acute  Combination therapy of levothyroxine and an antithyroid agent for hyperthyroidism is not indicated during pregnancy (see section 4.6). Special warnings and special precautions for use

Thyroxine has a narrow therapeutic index. Appropriate thyroxine dosage is based upon clinical assessment and laboratory monitoring of thyroid function tests. During the initial titration period, careful dosage titration and monitoring is necessary to avoid the consequences of under- or over-treatment. The symptoms of excessive thyroxine dosage are the same as many features of endogenous thyrotoxicosis. In order to ensure the continuity of different products of levothyroxine sodium in individual patients it should be emphasized that if patients are changed from one levothyroxine sodium product to another it should be done only with specific counseling and tight monitoring from their healthcare professional. Before starting therapy with thyroid hormones or before performing a thyroid suppression test, the following diseases or medical conditions should be excluded or treated: coronary failure, angina pectoris, arteriosclerosis, hypertension, pituitary insufficiency, adrenal insufficiency. Thyroid autonomy should also be excluded or treated before starting therapy with thyroid hormones. Treatment with thyroxine in patients with panhypopituitarism or other causes predisposing to adrenal insufficiency may cause reactions, including dizziness, weakness, malaise, weight loss, hypotension and adrenal crisis. It is advisable to initiate corticosteroid therapy before giving thyroxine in these cases. Special care is needed in the elderly and in patients with symptoms of myocardial insufficiency or ECG evidence of myocardial infarction or ischaemia and also those with diabetes mellitus or insipidus. Even slight drug-induced hyperthyroidism must be avoided in patients with coronary failure,
cardiac insufficiency or tachycardiac arrhythmias. Hence frequent checks of thyroid hormone
parameters must be made in these cases.
Thyroxine raises blood sugar levels and this may upset the stability of patients receiving anti-
diabetic agents.
In the case of secondary hypothyroidism the cause must be determined before replacement
therapy is given and if necessary replacement treatment of a compensated adrenal
insufficiency must be commenced.
Where thyroid autonomy is suspected a TRH test should be carried out or a suppression
scintigram obtained before treatment.
In postmenopausal women with hypothyroidism and an increased risk of osteoporosis supra-
physiological serum levels of levothyroxine should be avoided, and, therefore, thyroid function
should be checked closely.
Levothyroxine should not be given in hyperthyreotic states other than as concomitant
supplementation during anti-thyroid drug treatment of hyperthyroidism.
Thyroid hormones are not suitable for weight reduction. Physiological doses do not result in
any weight loss in euthyroid patients. Supraphysiological doses may cause severe or even
life-threatening undesirable effects.
4.5
Interaction with other medicinal products and other forms of interaction
 Thyroxine increases the effect of anticoagulants and it may be necessary to reduce the dose of anticoagulant if excessive hypoprothrombinaemia and bleeding are to be avoided.
 Phenytoin levels may be increased by thyroxine.
 Anticonvulsants such as carbamazepine and phenytoin enhance the metabolism of
thyroid hormones and may displace them from plasma proteins. Initiation or discontinuation of anticonvulsant therapy may alter thyroxine dose requirements.  If co-administered with cardiac glycosides, adjustment of dosage of cardiac glycoside  The effect of sympathomimetic agents are also enhanced.  Thyroxine increases receptor sensitivity to catecholamines thus accelerating the response  Aluminium-containing drugs (antacids, sucralfate) have been reported in the pertinent literature as potentially decreasing the effect of levothyroxine. Drugs containing levothyroxine should therefore be administered at least 2 hours prior to the administration of aluminium-containing drugs. Same is true for iron-containing drugs and calcium carbonate.  Ingestion of ion exchange resins such as, kayexalate and bile acid sequestrants such as cholestyramine and colestipol inhibits the absorption of levothyroxine sodium. Levothyroxine sodium should therefore be taken 4-5 hours before administration of such products.  Sevelamer may decrease levothyroxine absorption. Therefore, it is recommended that patients are monitored for changes in thyroid function at the start or end of concomitant treatment. If necessary, the levothyroxine dose has to be adjusted.  Salicylates, dicumarol, furosemide in high doses (250 mg), clofibrate and other substances can displace levothyroxine sodium from plasma proteins, resulting in an elevated fT4 fraction.  Co-administration of oral contraceptives, as well as a number of other drugs, including oestrogen, tamoxifene, clofibrate, methadone, and 5-fluorouracil may increase serum concentration of thyroxine-binding globulin, and therefore increase thyroxine dosage requirements.  Reports indicate that some HMG-CoA reductase inhibitors (statins), such as simvastatin and lovastatin, may increase thyroid hormone requirements in patients receiving thyroxine therapy. It is unknown if this occurs with all statins. Close monitoring of thyroid function and appropriate thyroxine dose adjustments may be necessary when thyroxine and statins are co-prescribed.  A number of drugs may decrease serum concentration of thyroxine-binding globulin, and therefore decrease thyroxine dosage requirements, including androgens and anabolic steroids.  Treatment with tyrosine kinase inhibitors (e.g., imatinib and sunitinib) was associated with increased thyroxine dosage requirements in hypothyroid patients.  Propylthiouracil, glucocorticoids, beta-sympatholytics, amiodarone and iodine containing contrast media: These substances inhibit the peripheral conversion of T4 to T3. Due to its high iodine content amiodarone can trigger hyperthyroidism as well as hypothyroidism. Particular caution is advised in the case of nodular goitre with possibly unrecognized autonomy.  Anti-diabetic agents: Levothyroxine may reduce the effect of antidiabetic agents. For this reason, blood glucose levels should be checked frequently at the start of thyroid hormone therapy and the dosage of the antidiabetic agent has to be adapted, if necessary.  Protease inhibitors (e.g. ritonavir, indinavir, lopinavir) may influence the effect of levothyroxine. Close monitoring of thyroid hormone parameters is recommended. If necessary, the levothyroxine dose has to be adjusted.  Sertraline, chloroquine/proguanil: These substances decrease the efficacy of levothyroxine and increase the serum TSH level.  Soy-containing compounds can decrease the intestinal absorption of levothyroxine. Therefore, a dosage adjustment of Eltroxin may be necessary, in particular at the beginning or after termination of nutrition with soy supplements.
A number of drugs may affect thyroid function tests and this should be borne in mind when
monitoring a patient on thyroxine therapy.
4.6
Pregnancy and lactation
Pregnancy Thyroxine has been taken by a large number of pregnant women and women of childbearing age without any form of definite disturbances in the reproductive process having been observed so far. Thyroid, hypo- or hyperactivity in the mother may, however, unfavourably influence the foetal outcome or well-being. Combination therapy of hyperthyroidism with levothyroxine and anti-thyroid agents is not indicated in pregnancy. Such combination would require higher doses of anti-thyroid agents, which are known to pass the placenta and to induce hypothyroidism in the infant.
Lactation
Thyroxine is excreted in breast milk in low concentrations and this may be sufficient to
interfere with neonatal screening for hypothroidism.
4.7
Effects on ability to drive and to use machines
From the pharmacokinetic and pharmacodynamic properties of thyroxine, treatment with thyroxine sodium would not be expected to interfere with ability to drive or operate machinery.
4.8 Undesirable

The frequency classification for these adverse reactions is not known due to a lack of robust
clinical trial data to accurately determine frequency estimates.

Blood and the lymphatic system disorders: Anginal pain, cardiac arrhythmias, palpitations,
tachycardia, increased blood pressure, heart failure, myocardial infarction. Immune system disorders: Hypersensitivity reactions such as skin rash and pruritus and
anaphylactic reactions.
Metabolism and nutrition disorders: Increased appetite, excessive loss of weight
Nervous system disorders: Excitability, insomnia, restlessness, headache, tremors, seizure.
Rare cases of pseudotumor cerebri (benign intracranial hypertension) have been reported
especially in children.
Respiratory, thoracic and mediastinal disorders: Dyspnoea.
Gastrointestinal disorders: Abdominal cramps, nausea, vomiting, diarrhoea.
Skin and subcutaneous tissue disorders: Sweating, flushing, hair loss.
Musculoskeletal, connective tissue and bone disorders: Cramps in the skeletal muscle,
muscular weakness, decreased bone mineral density.
Excessive dose may result in craniosynostosis in infants, and premature closure of epiphyses
in children with compromised adult height.
Reproductive system and breast disorders: Menstrual irregularity, impaired fertility.
General disorders and administration site conditions: Fatigue, heat intolerance, fever.
4.9 Overdose

Symptoms and Signs
In addition to exaggeration of side effects the following symptoms may be seen: agitation,
confusion, irritability, hyperactivity, headache, sweating, mydriasis, tachycardia, arrhythmias,
tachypnoea, pyrexia, increased bowel movements and convulsions. The appearance of
clinical hyper- thyroidism may be delayed for up to five days.

Treatment
The goal of therapy is restoration of clinical and biochemical euthyroid state by omitting or
reducing the thyroxine dosage, and other measures as needed depending on clinical status.
Treatment is symptomatic, and tachycardia has been controlled in adults by 40mg doses of
propranolol given every six hours and other symptoms by diazepam and/or chlorpromazine as
appropriate.

Further management should be as clinically indicated or as recommended by the national
poison centre, where available.
5. PHARMACOLOGICAL
PROPERTIES
Thyroxine sodium is the monosodium salt of the levorotary isomer of thyroxine. 5.1 Pharmacodynamic
properties
Thyroxine (T4) is a naturally occurring hormone produced by the thyroid gland and converted to the more active hormone tri-iodothyronine (T3) in peripheral tissues. The precise signals controlling the conversion of T4 to T3 within the cell are not known. The thyroid hormones are required for normal growth and development, particularly of the nervous system. They increase the resting or basal metabolic rate of the whole organism and have stimulatory effects on the heart, skeletal muscle, liver and kidney. Thyroid hormones enhance lipolysis and the utilization of carbohydrate. 100 mcg thyroxine is equivalent in activity to 20 to 30 mcg liothyronine/tri-iodothyronine or 60mg thyroid BP and/or local pharmacopoeia specification. 5.2 Pharmacokinetic
properties
Absorption Following oral administration the absorption of thyroxine is incomplete and variable especially when taken with food. The amount absorbed increases during fasting conditions. Distribution Thyroxine is nearly totally bound to serum protein. Metabolism The main pathway for the metabolism of thyroxine (T4) is its conversion, by de-iodination, to the active metabolite tri-iodothyronine (T3). Further de-iodination of T4 and T3 leads to production of inactive products. Elimination Thyroxine is eliminated slowly from the body with a half-life of approximately seven days in a normal person. This may be reduced in hyperthyroid states or increased in hypothyroid patients. In man approximately 20-40% of thyroxine is eliminated in the faeces and approximately 30 to 55% of a dose of thyroxine is excreted in the urine.
Special Patient Populations
 Renal impairment
Renal disease does not appear to have any significant effect on the disposition of thyroxine.
 Hepatic impairment
Hepatic disease does not appear to have any significant effect on the disposition of thyroxine.


5.3
Preclinical safety data

6. PHARMACEUTICAL
PARTICULARS
List of excipients
Microcrystalline cellulose (in triturate) Pre-gelatinised starch (Maize starch 1500)
6.2 Incompatibilities
6.3 Shelf-life
24 months.
6.4
Special precautions for storage
Do not store at temperatures exceeding 25C. Store in the original container, protected from light. Keep the container tightly closed. Nature and contents of container
Eltroxin 50 mcg tablets: White Opaque polypropylene bottles with tamper-evident,snap fit, low-density polyethylene closures, containing 100 or 1000 tablets. Eltroxin 100 mcg tablets: White Opaque polypropylene bottles with tamper-evident,snap fit, low-density polyethylene closures, containing 100 tablets. Instruction for use and handling
No special requirements.
7. MANUFACTURER
Aspen Bad Oldesloe GmBH, Bad Oldesloe, Germany REGISTRATION AUTHORISATION HOLDER
Perrigo Israel agencies Ltd., Lechi 29, Bnei-Brak, Israel. REGISTRATION AUTHORISATION NUMBER

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