This section is from the book "Materia Medica Pharmacy, Pharmacology And Therapeutics", by W. Hale White. Also available from Amazon: Materia Medica Pharmacy, Pharmacology And Therapeutics..
B. P., not official. A powder prepared from the fresh and healthy thyroid gland of the sheep.
Remove the fat and connective tissue directly the sheep is killed. Reject cystic, hypertrophied or otherwise abnormal glands. Mince. Dry at 90° to 100° F. 32.2° to 37.7° C.. Powder the dried product. Remove all fat by washing with petroleum spirit and again dry.
Light dull-brown powder with faint meat-like odor and taste and free from odor of putrescence. Liable to become damp and then it deteriorates.
The chief constituent is a proteid, which exists in the colloid matter and is called Thyroidin; it contains 9.3 per cent. of iodine and 0.5 per cent. of phosphorus.
Dose, 3 to 10 gr.; .20 to .60 gm.
Liquor Thyroidel - Solution of Thyroid. B. P., not official. A liquid prepared from the fresh and healthy thyroid gland of the sheep.
The fresh healthy glands are bruised with, for each gland, 34 minims 2.20 c.c. of glycerin and 34 minims 2.20 c.c. of a 0.5 per cent. solution of carbolic acid. Let stand for 24 hours, strain and add enough of the carbolic acid solution to make 100 minims 6.70 c.c..
A pinkish, turbid liquid, free from odor of putrescence. To be freshly prepared and kept in stoppered bottles. Strength. - 100 minims 6.70 c.c. represent one gland.
As of the powder.
Dose, 5 to 15 m.; .30 to 1.00 c.c.
Circulation. - Thyroid administered to man increases considerably the rate of the pulse, causes palpitation, enfeebles the cardiac beat, and makes the skin flushed and moist. Experiments on animals have failed to reveal the precise cause of this. The blood-pressure falls when a decoction of the gland is injected; the fall is vasomotor, for the heart is not affected. Ordinary doses produce no effect on the blood except an increase of lymphocytes.
Excretion. - The active constituents of thyroid gland are probably excreted entirely through the kidneys. Large doses may cause diarrhoea.
Metabolism. - The administration of thyroid leads to a greatly increased oxidation of all the tissues, consequently an excess of urea, uric acid and xanthin bases are excreted in the urine and more carbon dioxide by the lungs. It follows that large doses of thyroid reduce the body weight.
Kidneys. - The quantity of urine is increased by thyroid gland, which may cause sugar to appear in the urine.
Nervous system. - Occasionally a fine tremor, restlessness, and insomnia are caused by large doses.
It is known that human beings or monkeys whose thyroid is excised become myxoedematous, and that all sufferers from myxoedema have atrophied thyroid glands. If a preparation of sheep's thyroid is given to patients suffering from myxoedema, all the symptoms disappear, usually in about six weeks. The effect is as striking as anything in medicine. The solution is better than the powder, for that may decompose. It is best to begin with 5 m., .30 c.c. thrice daily, in water, gradually to increase the dose till 10 m., .60 c.c. are given, and when all symp-coms have disappeared it will be necessary for about 10 m., .60 c.c. to be taken twice a week for the rest of the patient's life to prevent recurrence. When the treatment was first introduced the glands were eaten, or transplanted under the skin, or the extract was administered subcutaneously; but equally good results are obtained by giving the solution or the powder by the mouth: compressed tablets of the powder are very convenient and much used. A diminution of certain goitres follows the giving of thyroid, but it is useless in exophthalmic goitre. Cretinism is also marvellously benefited, both mentally and bodily, by thyroid preparations, especially if given early in the patient's life. A few cases of imbecility in children, a few of climacteric insanity, and a few of tetany have been much improved by thyroid. Chronic psoriasis, which has resisted all other treatment, often disappears if the patient be put to bed and take daily enough of thyroid preparations to keep him on the brink of poisoning by them, but unfortunately the disease often returns when the treatment is discontinued.
Thyroid preparations have been much used for obesity, but the practice is not to be recommended. They must be carefully given to those suffering from cardiac disorder. A preparation called Iodothyrine, which contains the active principles of the gland, has been used lately. A milk-sugar triturate of this is given in daily dose of 15 to 30 gr.; 1. to 2. gm.
Poisoning. - An overdose of a thyroid preparation causes an exaggeration of the effects already described. The most evident are rapid pulse, slight pyrexia, headache, nausea, diarrhoea, restlessness, pains in the limbs, pruritus, and rarely delirium. These symptoms are termed " Thyroidism." If large doses be given to monkeys for a long period of time, a condition termed "Chronic Thyoidism " is produced. The symptoms of it are emaciation, muscular weakness, paresis, some alopecia, erection of some of the hairs on the head, proptosis, dilatation of pupils, widening of palpebral fissure, and death from asthenia. In some respects these monkeys resemble patients suffering from exophthalmic goitre. Very large doses taken for a long time make patients thin and also produce degeneration of the cardiac muscle so that permanent disability may result. Surgeons are especially liable to make this error.