This section is from the "A Handbook of Useful Drugs" book, by State Medical Examining and Licensing Boards.
The thyroid glands of the sheep, freed from fat, and cleaned, dried and powdered.
Properties : Desiccated thyroid gland is a yellowish, amorphous powder, having a slight, peculiar odor, and containing the active constituent of the thyroid tissue. It is partially soluble in water. The preparation should be standardized to contain 0.2 per cent, of iodin in organic combination.
Action and Uses : Dried thyroid gland acts chiefly if not entirely through a compound of iodin contained in it; the substance known commercially as "iodothyrin" seems sometimes, but not always, to represent the full activity of the gland. When given in therapeutically active doses thyroid causes an increase of the nitrogen of the urine and a decrease in weight; it usually increases the absorption of oxygen and the elimination of carbondioxid. It is one of the very few drugs which can properly be called stimulants of metabolism. The loss of weight is at first due to loss of water, then to increased metabolism of adipose tissue, although there is also an increased breaking down of protein unless the diet contains an abundance of protein. With larger, or long-continued doses there is a very rapid action of the heart, nervousness, tremors, headache, flushing of the surface, sweating and much more pronounced loss of weight.
Thyroid gland is of service in cases marked by deficient action of the gland. The most striking results are obtained in cretinism and myxedema and in the condition known as cachexia thyreopriva, due to the removal of the thyroid gland. The beneficial effects are seen in the improved condition of the skin, the reestablishment of perspiration and of a normal temperature, increased diuresis and loss of weight, improvement in the mental condition and, in young subjects, renewed growth, especially of the long bones and of the hair. In many cases after the more severe symptoms of hypothyroidism have disappeared, remarkably small doses suffice to keep the patient in an almost normal state; it is often necessary, however, to continue such small doses indefinitely.
Thyroid is efficacious in many cases of milder degrees of hypothyroidism; but these are often difficult to diagnose.
In some forms of goiter the function of the thyroid is defective and the administration of the dried gland is indicated; but in most cases of goiter its use is condemned. Thyroid has been much used in obesity, but it is indicated in only a small proportion of cases and it should be given in moderate amounts so as not to do harm by the destruction of proteins. The effects, which are marked at first, are not permanent. Thyroid gland has been used with reported success in various skin diseases, such as psoriasis and eczema, and also in certain cases of amenorrhea.
Dosage: 0.05 gm. or 1 grain should be given as the initial dose three times daily, increasing gradually until improvement is noted; its administration should be disconcontinued if toxic symptoms apppear. The patient should be careful of exertion and should take sufficient protein in his diet to compensate for increased loss of nitrogen from the action of the drug. The remedy may be given in powder, cachets or capsules. A dose of 0.6 gm. or 10 grains should rarely be exceeded.