 |
Historically, hypothyroidism is the first endocrine disorder to be treated by supplementation of the deficient hormone. |
|
|
It was treated with animal thyroid extracts in the past. |
|
|
This was followed by development of purified thyroid hormone preparations. |
Available thyroid hormone preparations are.
Thyroxine Sodium (T4 )
Triiodothyronine (T3 )
Combination of synthetic T3 and T 4
Thyroid USP (desiccated animal thyroid containingT3 and T4 in the form of thyroglobulin)
|
|
The mostly widely used and preferred preparation is synthetic T 4, thyroxine sodium . |
Goal of treatment
|
| To normalize the thyroid hormone status in peripheral tissues. |
Initiation of Therapy
Initial dosage may be based on
Age of patient,
Severity and duration of hypothyroidism.
Presence of associated disorders like ischaemic heart disease, adrenal insufficiency
Pediatric hypothyroidism .
|
|
The dosage of Thyroxine sodium for pediatric hypothyroidism varies with age and body weight |
|
|
Thyroxine should be given at a dose that maintains the serum total T4 or free T4 concentrations in the upper half of the normal range and serum TSH in the normal range. |
|
|
Thyroxine sodium therapy is usually initiated at the full replacement dose. |
|
|
Infants and neonates with very low or undetectable serum T4 levels ( < 5 mcg/ dL) should start at the higher end of the dosage range ( e.g.50 mcg daily) |
|
|
A lower starting dosage ( e. g. 25 mcg daily) should be considered for neonates at risk of cardiac failure, increasing every few days until a full maintenance dose is reached. |
|
|
In children with severe, long-standing hypothyroidism, Thyroxine sodium should be initiated gradually, with an initial dose of 25 mcg for two weeks, and then increasing the dose by 25 mcg every 2 to 4 weeks until the desired dose based on serum T 4 and TSH levels is achieved. |
Age |
Daily dose per Kg body weight + |
|
0-3 months 3-6 months 6-12 months 1-5 years 6-12 years > 12 years Growth and puberty complete |
10-15 mcg 8-10 mcg 6-8 mcg 5-6 mcg 4-5 mcg 2-3 mcg 1.6 mcg |
+ To be adjusted on the basis of the clinical response and laboratory test.
Adults
|
|
Young, healthy adults with no cardiac / respiratory disease are started with 1.6 mcg/kg/day of thyroxine sodium administered once daily. |
|
|
In elderly patients or in younger patients with cardiovascular disease, dose required is lower than the usual adult dose. i.e. < lmcg/kg/day, administered once a day. |
|
|
To start with in elderly patients 12.5 to 50 mcg of thyroxine sodium are given daily and increment of 12.5 to 25 mcg are made at 3-6 week intervals if required. |
|
|
Women who are maintained on thyroxine sodium during pregnancy may require increased doses. |
Treatment of sub clinical hypothyroidism
|
|
Treatment of sub clinical hypothyroidism, when indicated may require lower than usual replacement doses; (lmcg/kg/day). |
|
|
Patients for whom treatment is not initiated should be monitored yearly for changes in clinical status, TSH and thyroid antibodies. |
 |
In patients with associated adrenal insufficiency, low does of thyroxine sodium are started only after initial treatment with glucocorticoids. |