Eltroxin Tablet
Thyroxine/Levothyroxine Sodium
100mcg
Glaxo SmithKline Pharmaceuticals Ltd.
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Available as:
Indications
Eltroxin Tablet is used for:
Hypothyroidism, TSH suppression, Myxoedema coma
Adult Dose
Oral
Mild Hypothyroidism
1.7 mcg/kg or 100-125 mcg PO qDay; not to exceed 300 mcg/day
>50 years (or <50 yr with CV disease)
Usual initial dose: 25-50 mcg/day
May adjust dose by 12.5-25 mcg q6-8Week
>50 years with CV disease
Usual initial dose: 12.5-25 mcg PO qDay
May adjust dose by 12.5-25 mcg q4-6weeks until patient becomes euthyroid and serum TSH concentration normalized; adjustments q6-8weeks also used
Dose range: 100-125 mcg PO qDay
Severe Hypothyroidism
Initial: 12.5-25 mcg PO qDay
Adjust dose by 25 mcg/day q2-4Week PRN
Subclinical Hypothyroidism
Initial: 1 mcg/kg PO qDay may be adequate, OR
If replacement therapy not initiated, monitor patient annually for clinical status
TSH suppression
For thyrotropin-dependent well-differentiated thyroid cancer: Doses >2 mcg/kg/day may be given as a single dose to suppress TSH to <0.1 MIU/L.
For benign nodules and nontoxic multinodular goitre: Target TSH is generally higher at 0.1-0.5 MIU/L for nodules and 0.5-1 MIU/L for multinodular goitre.
Child Dose
Oral
Hypothyroidism
Age 1-3 months
10-15 mcg/kg/day PO
Use lower starting dose (25 mcg/day) if patient at risk of cardiac failure; if initial serum T4 lower than 5 mcg/dL begin treatment at higher dose (50 mcg/day)
Age 3-6 months
8-10 mcg/kg/day PO, OR
25-50 mcg/day PO
Age 6-12 months
6-8 mcg/kg/day PO, OR
50-75 mcg/day PO
Age 1-5 years
5-6 mcg/kg/day PO, OR
75-100 mcg/day PO
Age 6-12 years
4-5 mcg/kg/day PO, OR
100-125 mcg/day PO
>12 years
2-3 mcg/kg/day PO, OR
150 mcg/day PO
Start children with severe or chronic hypothyroidism at 25 mcg/day; adjust dose by 25 mcg qweek
Renal Dose
Administration
Should be taken on an empty stomach with full glass of water. Take on an empty stomach ½-1 hr before meals.
Contra Indications
Untreated hyperthyroidism; uncorrected adrenal failure; recent MI.
Precautions
Patients w/ CV (e.g. angina, heart failure, HTN), DM and diabetes insipidus, epilepsy, pre-existing myasthenia syndrome, long-standing hypothyroidism. Elderly, pregnancy and lactation. Monitoring Parameters Monitor thyroid function test, clinical signs of hypo- and hyperthyroidism, heart rate and BP.
Lactation: Enters breast milk; use caution
Pregnancy-Lactation
Interactions
Reduced absorption w/ iron, antacids, bile acid sequestrants, colestyramine, simeticone, Ca carbonate, sucralfate, cation exchange resins. Reduced tri-iodothyronine serum levels w/ amiodarone and propranolol. Reduced serum levels of thyroxine w/ carbamazepine, phenytoin, phenobarbital, rifampicin, lithium, oestrogens, sertraline. Androgens may decrease levothyroxine-binding globulins serum levels. May alter requirements of antidiabetic drugs. Increased risk of significant HTN and tachycardia w/ ketamine. Increased metabolic demands w/ sympathomimetics (e.g. epinephrine). May increase anticoagulant effect of warfarin.
Adverse Effects
Side effects of Thyroxine/Levothyroxine Sodium :
Nervousness, excitability, tremor, muscle weakness, fatigue, cramps; sweating, flushing, heat intolerance, headache, fever, insomnia, tachycardia, palpitations, restlessness, anginal pain, HTN, severe depression, difficulty in sleeping, excessive wt loss; menstrual irregularities; diarrhoea, vomiting, psychosis or agitation. Increased bone resorption and reduced bone mineral density, especially in post-menopausal women; elevated LFT.
Potentially Fatal: Thyrotoxic crisis including convulsions, cardiac arrhythmia, heart failure, coma.
Mechanism of Action
Levothyroxine Na is a synthetic form of thyroxine which increases the basal metabolic rate (BMR) and the utilisation and mobilisation of glycogen stores and stimulates protein synthesis. It is also involved in normal metabolism, growth and development. These effects are mediated at the cellular level by the thyroxine metabolite, tri-iodothyronine.
Note
Eltroxin 100mcg Tablet manufactured by Glaxo SmithKline Pharmaceuticals Ltd.. Its generic name is Thyroxine/Levothyroxine Sodium. Eltroxin is availble in Nepal.
Farmaco Nepal drug index information on Eltroxin Tablet is not intended for diagnosis, medical advice or treatment; neither intended to be a substitute for the exercise of professional judgment.