19 Reproductive system Flashcards
19.01 OESTROGENS AND ANTI-OESTROGENS
Natural and synthetic oestrogens: raloxifene; anti-oestrogens: clomifene, tamoxifen - actions
oestrogen controls the proliferative phase of endometrium and exerts negative feedback on the anterior pituitary
in addition to the reproductive system, oestrogens have metabolic and vascular effects
19.01 OESTROGENS AND ANTI-OESTROGENS
Natural and synthetic oestrogens, raloxifene; anti-oestrogens: clomifene, tamoxifen - MOA
bind to nuclear receptors and exert genomic effects
raloxifene has agonist effects at bone but antagonist on reproductive organs
clomifene is a competitive antagonist of oestrogen receptors at the anterior pituitary, and increases gonadotrophin secretion by preventing negative feedback
19.01 OESTROGENS AND ANTI-OESTROGENS
Natural and synthetic oestrogens, raloxifene; anti-oestrogens: clomifene, tamoxifen - abs/distrib/elim
many different formulations available (oral, topical, implantable, transdermal)
19.01 OESTROGENS AND ANTI-OESTROGENS
Natural and synthetic oestrogens, raloxifene; anti-oestrogens: clomifene, tamoxifen - clinical use
oestrogens are used in primary ovarian failure, menopausal symptoms and in female contraception
raloxifene is for osteoporosis
anti-oestrogens are used for inducing ovulation (clomifene) and for oestrogen-sensitive breast cancer (tamoxifen)
19.01 OESTROGENS AND ANTI-OESTROGENS
Natural and synthetic oestrogens, raloxifene; anti-oestrogens: clomifene, tamoxifen - adverse effects
varies with formulation and clinical setting but may include breast tenderness, water retention, venous thromboembolism
small increase in risk of breast and endometrial cancer in menopausal women
clomifene causes menopausal-like hot flushes, ovarian enlargement
19.02 PROGESTOGENS AND ANTI-PROGESTOGENS
Progestogens: medroxyprogesterone, norethisterone, desogestrel, cyproterone; anti-progestogens: mifepristone - actions
progestogens control the secretory phase of endometrium and exert negative feedback on the anterior pituitary and hypothalamus
weak androgenic action
19.02 PROGESTOGENS AND ANTI-PROGESTOGENS
Progestogens: medroxyprogesterone, norethisterone, desogestrel, cyproterone; anti-progestogens: mifepristone - MOA
bind to intracellular receptors and alter gene expression
cyproterone has weak progestational activity but is a partial agonist at androgen receptors in the hypothalamus
19.02 PROGESTOGENS AND ANTI-PROGESTOGENS
Progestogens: medroxyprogesterone, norethisterone, desogestrel, cyproterone; anti-progestogens: mifepristone - abs/distrib/elim
many different formulations (oral, injectable, implantable device)
examples include levonorgestrel as a SC depot or as an intrauterine contraceptive system
19.02 PROGESTOGENS AND ANTI-PROGESTOGENS
Progestogens: medroxyprogesterone, norethisterone, desogestrel, cyproterone; anti-progestogens: mifepristone - clinical use
female contraception, including post-coital emergency contraception
endometriosis
anti-progestogens (mifepristone) used in medical termination of pregnancy
cyproterone used to suppress hyperandrogenism
19.02 PROGESTOGENS AND ANTI-PROGESTOGENS
Progestogens: medroxyprogesterone, norethisterone, desogestrel, cyproterone; anti-progestogens: mifepristone - adverse effects
acne, fluid retention, weight change, menstrual disturbance
19.03 COMBINED ORAL CONTRACEPTIVE PILL
Oestrogen and a progestogen: ethinylestradiol + norethisterone; ethinylestradiol + desogestrel - actions and use
prevention of pregnancy
19.03 COMBINED ORAL CONTRACEPTIVE PILL
Oestrogen and a progestogen: ethinylestradiol + norethisterone; ethinylestradiol + desogestrel - MOA
oestrogen suppresses the development of the ovarian follicle by inhibiting follicle-stimulating hormone (FSH) release from the anterior pituitary
progestogen prevents ovulation by inhibiting luteinizing hormone (LH) release
together, they make the endometrium unsuitable for implantation of the ovum
19.03 COMBINED ORAL CONTRACEPTIVE PILL
Oestrogen and a progestogen: ethinylestradiol + norethisterone; ethinylestradiol + desogestrel - abs/distrib/elim
given orally
taken cyclically for 21 days out of 28 days
19.03 COMBINED ORAL CONTRACEPTIVE PILL
Oestrogen and a progestogen: ethinylestradiol + norethisterone; ethinylestradiol + desogestrel - adverse effects
weight gain, flushing, mood changes, dizziness, acne or skin pigmentation, transient rise of blood pressure
some risk of thromboembolism
19.04 GONADOTROPHINS
GnRH analogues (gonadorelin, leuprorelin) and inhibitors (danazol) - actions and MOA
pulsatile regimens of gonadotrophin-releasing hormone (GnRH) analogues stimulate gonadotrophin release but have inhibitory effects when given continuously
danazol is a modified progestogen that inhibits gonadal function by suppressing the mid-cycle surge of gonadotrophins
19.04 GONADOTROPHINS
GnRH analogues (gonadorelin, leuprorelin) and inhibitors (danazol) - abs/distrib/elim
GnRH analogues are given by SC injection or nasal spray intermittently, or through a depot injection for continuous use
danazol is given orally
19.04 GONADOTROPHINS
GnRH analogues (gonadorelin, leuprorelin) and inhibitors (danazol) - clinical use
GnRH analogues are used in infertility
longer term use for gonadal suppression in prostate cancer and endometriosis
danazol is used in the treatment of endometriosis and gynaecomastia
19.04 GONADOTROPHINS
GnRH analogues (gonadorelin, leuprorelin) and inhibitors (danazol) - adverse effects
adverse effects of GnRH analogues vary depending on whether treatment is used for stimulation (hypergonadism) or inhibition (hypogonadism)
moderate effects are common with danazol: weight gain, acne, hot flushes, amenorrhoea, masculinisation (hirsutism, deepening of voice, etc.)
19.05 UTERINE STIMULANTS
Oxytocin - actions
contracts the uterus causing coordinated contractions that travel from fundus to cervix with complete relaxation between contractions
has vasodilator action
19.05 UTERINE STIMULANTS
Oxytocin - MOA
acts on oxytocin receptors in the smooth muscle of the myometrium
contracts myoepithelial cells in the breast to release milk
vasodilator and antidiuretic action
19.05 UTERINE STIMULANTS
Oxytocin - abs/distrib/elim
usually given by IV infusion
can be given IM
inactivated by the liver and kidneys and by circulating oxytocinase