Sex steroid pharmacology Flashcards
Oestrogen - pharmacokinetics&excretion, actions, side effects
well absorbed in GI tract, skin and mucous membranes, metabolised by the liver, excreted in the urine as glucuronides and sulfates
mild anabolic action, sodium and water retention, lowers LDL, decreases bone resorption, increases blood coagulability
breast tenderness, n&v, water retention, increased blood coagulability, thromboembolism, impaired glucose tolerance, endometrial and breast hyperplasia and cancer, ovarian metaplasia and cancer
Progesterone - pharmacokinetics&excretion, actions, side effects
bound to albumin, some is stored in adipose tissue, metabolised in liver and metabolites are excreted in the urine conjugated to glucuronic acid
secretory endometrium, anabolic, increases bone mineral density, fluid retention, mood changes, maintains pregnancy
weight gain, fluid retention, anabolic, acne, n&v, irritability, depression, PMS, lack of concentration
Testosterone - actions
male 2ry characteristics, anabolic, acne, voice changes, increases aggression, metabolic - adverse effects on lipid profiles hence increased risk of atherosclerotic disease in males
What are the pharmacokinetics of oral contraceptives and what affect do soya protein products have?
metabolised by liver CYP450 enzymes, therefore the efficacy is reduced by enzyme inducing drugs e.g. rifampin, carbamazepine. This is because they all increase the production of CYP450
soya protein products enhance oestrogen absorption and reduce its storage in adipose and muscle so reduces the half life
Why is HRT used and what are the risks (unopposed and opposed oestrogen)?
it is use to help hot flushes/sweats/dyspareunia/osteoporosis but does not aid in preventing heart disease
unopposed oestrogen increases risk of developing endometrial and ovarian cancers
opposed oestrogen increases risk of breast cancer
increased risk of thromboembolism, CVD risk, increased risk of stroke in the use of oral oestrogen
What is RU486 - mifepristone and what does it do?
it is a progesterone receptor antagonist, it sensitises the myometrium to prostaglandin induced contractions and is used for pregnancy termination
What are 2 examples of SERM?
tamoxifen and rakoxifene (manages menopause)
What is clomiphene and how does it work?
used in treatment of anovulation, competes with oestrogen for ER biding and leads to ovulation through increased production of anterior pituitary hormones
What is tamoxifen and how does it work, what are its converse effects?
it is a pro drug and has little affinity for ER.
it is metabolised in the liver to the active derivatives which bind competitively. in the endometrium it acts as an ER agonist but in the breast it acts as an ER antagonist and binding of the ER following tamoxifen treatment causes cells to arrest the cell cycle
What is ulipristal acetate, its uses and how does it work?
it is a selective progesterone receptor modulator which is used for emergency contraception and the primary mode of action is through delay or inhibition of ovulation, it is also effective treatment for uterine fibroids
