Sex hormones and related drugs
Sex hormones and related drugs are used to increase levels of female and male sex hormones or block their release or action.
Various forms of sex hormones and sex hormone antagonists (chemicals that block the release or action of hormones) are used to treat disorders in which there are abnormally high or low levels of sex hormones in the body.
A brain area called the hypothalamus produces gonadotrophin-releasing hormone. This hormone then stimulates the further production of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) by the pituitary gland, a pea-sized gland that is located at the base of the brain. FSH and LH, in turn, regulate sexual development by stimulating the release of the sex hormones: testosterone by the testes in males, and oestrogen and progesterone by the ovaries in females.
|Female sex hormones: Estradiol, Ethinylestradiol, Levonorgestrel, Medroxyprogesterone, Norgestrel, Tibolone||Anti-oestrogens: Clomifene, Tamoxifen, Gonadotrophins (see Drugs for infertility)|
|Danazol:||Male sex hormones: Mesterolone, Testosterone|
|Antiandrogens: Bicalutamide, Cyproterone acetate, Finasteride, Flutamide||Gonadorelin and gonadorelin analogues: Buserelin, Gonadorelin, Goserelin, Leuprorelin, Nafarelin, Triptorelin|
What are the types of sex hormone and related drugs?
The hormones and drugs used to treat hormonal disorders in women include forms of the female hormones oestrogen and progesterone. Anti-oestrogens are sex hormone antagonists and may be used to block the action of oestrogen. The male hormone testosterone is used to treat certain hormonal disorders in boys and men; male sex hormone antagonists called antiandrogens may also be necessary to block the action of testosterone. Gonadorelin, a synthetic form of gonadotrophin-releasing hormone, and gonadorelin analogues, which block the release of gonadotrophin, are also used to treat hormonal disorders.
Female sex hormones
Synthetic forms of the hormones oestrogen and progesterone have several uses. By far the most widespread use is as oral contraceptives (see Contraception), in which the two hormones are taken together, or progesterone is taken alone, to prevent pregnancy. Oestrogen and progesterone are used in lower doses in hormone replacement therapy to relieve the symptoms of the menopause.
The drugs may be administered by injection, taken orally, or used as skin patches, depending on the type of drug and the reason for its use. Side effects are most likely to occur at the higher doses and may include fluid retention, headache, nausea, weight gain, and depression. In addition, premenopausal women may experience some bleeding between periods while taking synthetic sex hormone drugs.
Clomifene is often used to treat infertility in women (see Female infertility). Because clomifene stimulates egg production, there is a risk of multiple pregnancy. Possible side effects of clomifene include visual disturbances, hot flushes, abdominal discomfort, nausea, and vomiting. Tamoxifen is used to treat breast cancer and some forms of female infertility. Prolonged use of tamoxifen may be associated with a slightly increased risk of uterine cancer. Tamoxifen may cause menstrual irregularities, abnormal vaginal bleeding, and pelvic pain; if you experience any of these symptoms, you should see your doctor promptly. Other side effects include hot flushes, genital irritation, headache, and light-headedness. There may be an increased risk of thromboembolism (see Thrombosis and embolism).
Male sex hormones
Synthetic forms of male sex hormones are used to treat certain conditions caused by low levels of testosterone, including delayed puberty in boys (see Abnormal puberty in males) and decreased libido in men (see Decreased sex drive). Given in low doses, synthetic testosterone mimics the action of the natural hormone, and side effects are rare.
Some antiandrogens, such as finasteride, are used to treat an enlarged prostate gland; others, such as flutamide, are used in the treatment of prostate cancer. In addition, virilization, in which women develop a number of masculine characteristics such as excessive facial and body hair, may also be treated using one of these drugs, usually cyproterone acetate. Antiandrogens act by blocking the action of the natural male sex hormones. A common side effect of treatment with antiandrogens is tiredness. The drugs can also affect liver function and are not normally given to anyone with a history of liver problems.
This drug is used to treat endometriosis. Side effects of danazol include hirsutism (excessive hair growth), acne, and voice changes, as well as changes in libido and disturbances to the menstrual cycle.
Gonadorelin and gonadorelin analogues
Gonadorelin is a synthesized version of a natural hormone called gonadotrophin-releasing hormone. This drug is used to assess the function of the pituitary gland.
Gonadorelin analogues are prescribed for certain female reproductive disorders, such as endometriosis and female infertility. These drugs may also be used to treat prostate cancer and breast cancer. Their initial effect is to stimulate the release of LH and FSH from the pituitary gland.
When given over a long period of time, gonadorelin analogues reduce production of these hormones. This, in turn, inhibits the release of oestrogen, progesterone, and testosterone. Gonadorelin analogues are given by injection or as a nasal spray. Side effects may include acne, nausea and vomiting, and headache. In premenopausal women these drugs may cause bleeding between periods, hot flushes, and increased sweating.
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