Hypothyroidism is a syndrome caused by a deficiency of thyroid hormones, and is displayed largely by a reversible slowing down of all body functions. There is prominent retardation of growth and development that results in dwarfism and irreparable mental retardation in infants and children. Hypothyroidism can occur with or without thyroid enlargement. The laboratory diagnosis of hypothyroidism in the adult is easily made by the combination of a low free thyroxine and elevated serum TSH. The most common cause of hypothyroidism currently is perhaps Hashimoto’s thyroiditis, an immunologic disorder in genetically predisposed individuals. In this condition, there is evidence of humoral immunity in the presence of antithyroid antibodies and lymphocyte sensitization to thyroid antigens. Certain medications can also cause hypothyroidism.
Treatment of Hypothyroidism
Standard treatment for hypothyroidism involves daily use of the synthetic thyroid hormone levothyroxine, administered as either a branded or generic preparation. This oral medication restores adequate hormone levels, reversing the signs and symptoms of hypothyroidism. Infants and children require more thyroxine per kilogram of body weight than adults. The average dosage for an infant 1–6 months of age is 10–15 microgram per kilogram per day, whereas the average dosage for an adult is about 1.7 microgram per kilogram per day. Older adults less than 65 years of age may require less thyroxine for replacement. There is some variability in the absorption of thyroxine, so this dosage will vary from patient to patient.
Levothyroxine (T4) (generic, Synthroid, Levoxyl, Levo-T, Levothroid, Levolet, Novothyrox, Tirosint, Unithroid) – is a synthetic thyroid hormone that is chemically identical to thyroxine (T4), which is naturally secreted by the follicular cells of the thyroid gland. Levothyroxine is typically used to treat hypothyroidism in patients who require lifelong thyroid hormone therapy. It may also be used to treat goiter via its ability to lower thyroid-stimulating hormone (TSH), a hormone that is considered goiter-inducing. Levothyroxine is also used as interventional therapy in people with nodular thyroid disease or thyroid cancer to suppress thyroid-stimulating hormone (TSH) secretion. Synthroid is in the top ten of most commonly prescribed medications.
Liothyronine (T3) (generic, Cytomel) – is a synthetic form of thyroid hormone (T3) used to treat hypothyroidism and myxedema coma. It is also used as an augmentation strategy in treating major depressive disorder when used in combination with antidepressants. Liothyronine is the most potent form of thyroid hormone. As a salt of triiodothyronine (T3), it is chemically similar and pharmacologically equivalent to T3. As such, it acts on the body to increase the basal metabolic rate, affect protein synthesis and increase the body’s sensitivity to catecholamines by permissiveness. The shorter half-life of this drug compared to levothyroxine can inform the patients if they have been dosed properly.
Liotrix (a 4:1 ratio of T4: T3) (Thyrolar) – is used to replenish thyroid hormones in thyroid deficiency and hypothyroidism. This drug can also be used for other purposes such as: Hashimoto’s thyroiditis, congenital hypothyroidism, Goiter treatment with thyroid stimulating hormone suppression, management of thyroid cancer, and as an agent in a differential diagnosis of hyperthyroidism and thyroid gland autonomy.
Thyroid desiccated [USP] (generic, Armour, Nature-Throid, Westhroid) – are prescription medications made from the thyroid glands of pigs. It is the only thyroid medication that contains all four thyroid hormones that our bodies make; T4, T3, T2, and T1. In addition its iodine, thyroglobulin protein and glandular tissue content that have useful functions in the body.