Thyroid disorders are mainly of two types - hypothyroidism and hyperthyroidism. Underfunctioning thyroid gland with decreased thyroid hormones called T3 and T4 are seen in hypothyroidism. It is indicated by a slowed metabolism presenting as fatigue, weight gain, cold intolerance and constipation. Overproduction of T3 and T4 is seen in hyperthyroidism. It presents as a fast heart rate, weight loss, sweating, and anxiety.
Patients with hypothyroidism need thyroid hormone supplements in some form to aid their metabolism. Available medications include synthetic T3, also known as liothyronine (Triostat, Cytomel,) and synthetic T4, also known as levothyroxine (Synthroid, Unithroid, Levoxyl). Iron, calcium, and antacids can interfere with the absorption of levothyroxine. Desiccated thyroid is derived from the thyroid glands of pigs. It is sold under the brand names Armour Thyroid and Nature-throid. Adverse effects are due to overdosing and present with symptoms of hyperthyroidism. T3 and T4 containing medications should be taken on an empty stomach at preferably the same time every day.
Hyperthyroidism is characterized by excessive production of thyroid hormones. Methimazole (Tapazole) and propylthiouracil (Propacil) are medications that are used to treat hyperthyroidism, e.g., in Grave’s disease. Propylthiouracil and methimazole decrease the production of new thyroid hormone. Common adverse effects of methimazole include nausea, rash, joint pain, and hair loss. Serious adverse effects like agranulocytosis (severely decreased white blood cell count) and liver toxicity may occur. It is contraindicated in the first trimester of pregnancy due to teratogenicity. Propylthiouracil adverse effects include rash, loss of taste, headache, hypersensitivity, renal dysfunction, jaundice, and hepatic failure. Rarely, agranulocytosis may occur. Both methimazole and propylthiouracil increase the effect of warfarin and may cause bleeding.
Radioactive iodine: Radioactive iodine called I-131 is sold under brand names Iodotrope, i3odine Max, and Hicon. It is used in the treatment of hyperthyroidism and thyroid cancer. To avoid radiation exposure, radioactive iodine should not be used in pregnant and nursing women. Treatment with radioactive iodine will eventually cause hypothyroidism.
Androgens and testosterone: Androgens are hormones produced predominantly by testes, ovaries, and adrenal glands. Some are naturally occurring, while others are synthetic. Androgens are used to help with fertility issues, increase muscle mass, as hormone replacement in hypogonadism and other conditions, and to treat endometriosis and certain types of breast cancer. The most commonly used androgen is testosterone (Testim, Androgel, Depo-testosterone, Fortesta, Xyosted, Jatenzo, Aveed). Other androgens include methyltestosterone (Methitest, Android, Virilon), fluoxymesterone (Androxy, Halotestin), dihydrotestosterone or androstanolone (Andractim), danazol (Danocrine), DHEA, and testolactone (Teslac). Synthetic versions of testosterone are known as anabolic steroids e.g., Testim, Androgel, danazol, fluoxymesterone, mesterolone, methyltestosterone, nandrolone (Durabalin), oxandrolone (Oxandrin) and oxymetholone (Anadrol). Testosterone is available as injection, gel, tablet, capsule, pellets, patch, implant, and solution forms. Adverse effects include acne, hair loss, enlargement of the prostate gland, polycythemia or increase in red blood cell count, virilization in females (deepening of voice, enlarged clitoris, hirsutism), jaundice and mood changes. Contraindications include prostate cancer, pregnancy, and severe heart disease. Testosterone is a controlled medication under Schedule III due to its potential for abuse.
Estrogens: Estrogen is a naturally occurring hormone that is primarily produced by the ovaries and in small amounts by the adrenal gland and fat cells. Women have high levels of estrogen in their reproductive life while small amounts are also present in men and contribute to reproductive health, metabolism, bone density, cardiovascular health, and brain health. The three naturally occurring forms of estrogen are estradiol (E2), estrone (E1) and estriol (E3). Synthetic versions include ethinyl estradiol, conjugated estrogens, estradiol valerate, esterified estrogens, and estropipate. Synthetic estrogen is used as hormone replacement therapy in the treatment of menopausal symptoms, osteoporosis, ovarian failure, and certain breast and prostate cancers. It is available in the form of tablets, capsules, cream, gel, patch, sprays, injections, vaginal suppositories, and rings. Commonly available brands include Alora, Climara, Bivigel, Botti, Estrace, Estraderm, Yuvafem, Vagifem, Premarin, Femring, Ogen, and Estring. Adverse effects include breast tenderness, nausea, headache, weight gain, abnormal uterine bleeding, and rarely, stroke, jaundice, blood clots, and heart attack. Unopposed estrogen may cause endometrial cancer. Diethylstilbesterol or DES is a synthetic form of estrogen that is rarely used now as it has been shown to cause birth defects, vaginal and cervical cancers to progeny after intrauterine exposure.
Estrogen and progestin combinations: Progesterone is a hormone produced by the ovaries and placenta. Along with estrogen it is essential for reproductive health in females. Many types of synthetic progesterones, also known as progestins, are available, including desogestrel, levonorgestrel, megestrol, norethisterone, and medroxyprogesterone. Combination drugs containing estrogen and progesterone are commonly used as birth control pills or oral contraceptives, and hormone replacement therapy (HRT) for the treatment of menopausal symptoms, acne, regulation of menstrual cycle, and osteoporosis. Commonly available brands include Estarylla, Yaz, Femynar, Mili, Vylibra, Previfem, Nymyo, Yasmin, Loryna, Delyla, NuvaRing and Xulane. Adverse effects include nausea, change in bowel habits, weight fluctuations, irregular bleeding, headache, blood clots, depression, and tumors in the liver. Using oral contraceptives increases the risk of heart attacks, stroke, and blood clots in cigarette smokers and those older than 35 years of age. Taking birth control pills with certain supplements like St.John’s wort may cause contraceptive failure by decreasing the levels of estrogen and progesterone.
Emergency contraception: There are various modes of emergency contraception including copper intrauterine devices or IUDs and emergency contraceptive pills or ECPs. ECPs include ulipristal acetate in a single dose, levonorgestrel in a single or two split doses, and combined ethinyl estradiol and levonorgestrel in two doses. ECPs need to be administered within 3-5 days of unprotected sexual intercourse. Ulipristal blocks the effect of progesterone and is a selective progesterone receptor modulator. Common brand names include Ella for ulipristal and Plan B, Plan B One Step, EContra EZ, My Way, and Next Choice for levonorgestrel containing ECPs.
5 alpha reductase inhibitors: These drugs block the enzyme 5-alpha-reductase, which converts testosterone to dihydrotestosterone or DHT. DHT is normally involved in the development of male external genitalia, male pattern hair distribution, and prostate growth. They are used in the treatment of BPH (benign prostatic hyperplasia) and male pattern baldness. Examples include finasteride (Propecia, Proscar) and dutasteride (Avodart). Adverse effects include impotence, gynecomastia, and decreased libido.
Aromatase inhibitors: The enzyme aromatase converts androgens into estrogens. Aromatase inhibitors block the enzyme aromatase and reduce the levels of estrogen. They are used in the prevention and treatment of estrogen receptor or ER positive breast cancers. Examples include anastrozole (Arimidex), letrozole (Femara), exemestane (Aromasin) and fadrozole (Afema). They may cause muscle pain and stiffness, skin ulcers, insomnia, hot flashes, jaundice, sexual dysfunction and osteoporosis.
Selective estrogen receptor modulators or SERMs: SERMs affect the action of estrogen on tissues like breast and bone. Several types are available, e.g., tamoxifen (Nolvadex, Soltamex, Tamofen), raloxifene (Evista, toremifene (Fareston), and clomiphene (Clomid, Serophene). Uses are guided by specific tissue effects, e.g.,. tamoxifen and raloxifene are used to treat and prevent breast cancer, raloxifene is used in osteoporosis, toremifene is used in metastatic breast cancer, and clomiphene is used to treat infertility in PCOS (polycystic ovarian syndrome). Adverse effects include hot flashes, night sweats, irregular periods, decreased libido, blood clots, uterine cancer, and stroke.