Sex Steroids Flashcards
Name the three major sex hormones
Oestrogen, progesterone, testosterone
What are the major effects of oestradiol (strongest of the oestrogen hormones)?
Stimulates growth of the endometrium and breast
Stimulates production of progesterone receptors
What are the major effects of progesterone?
Stimulates growth of the endometrium and breast
Maintains pregnancy
Inhibits production of oestrogen receptors
What are the major effects of testosterone?
Stimulates male characteristics:
Hairy body, deep voice, anabolism, aggression
Sex steroids are synthesised from what?
Cholesterol
Oral contraceptive pills exist in two types, what are they?
COCP (combined oral contraceptive pill)
POP (progestin only pill)
In which three ways can the COCP be administered?
Monophasic - each tablet has fixed amount of oestrogen and progesterone (21 days)
Biphasic - fixed oestrogen, progestin increases in second half of cycle (21 days)
Triphasic - amount of oestrogen fixed or variable, progestin increases in 3 equal phases (21 days + 7day placebo)
What is the mode of action of the COCP?
Suppresses ovulation by inhibiting FSH and LH
Holds ovary in non-dominant follicular state
Adverse effect on cervical mucus (more viscous)
Adverse effect on endometrium (remains atrophic)
Give some ADRs of the COCP
Venous thromboembolism MI Hypertension Decreased glucose tolerance Mood swings Headaches
Why should you be careful when prescribing COCP alongside certain other medications?
Give some examples of such medications
The COCP is metabolised by CYP450
Therefore efficacy is reduced by enzyme inducing drugs such as: Anti-epilepsy drugs- Carbamazepine/phenytoin
Antibiotics - Rafampicin, Rifabutin
St John’s Wort
How does the POP work as a contraceptive?
Suppression of oestrogen
Thickens cervical mucus
Endometrium remains thin
What is the definition of a “missed pill”?
A missed pill >24 hours after the time it was meant to be taken
If one pill is missed, what is the general advice?
Take the missed pill immediately, even if it means taking two pills in one day
Continue taking the rest of the pack as normal
If two pills are missed, what is the general advice?
Take the missed pill immediately, even if it means taking two pills in one day
Continue taking the rest of the pack as normal
USE EXTRA CONTRACEPTION FOR THE FOLLOWING SEVEN DAYS
Which emergency contraception can be taken up to 72hours post coitus?
Levonorgestrel 1.5mg
Which emergency contraception can be taken up to 120 hours post coitus?
EllaOne 30mg
Copper IUD
Which two types of post menopausal hormone replacement therapy exist?
ERT (oestrogen replacement therapy)
HRT (hormone replacement therapy)
Why might we prescribe HRT?
To relieve symptoms auch as hot flushes, sweats, vaginal dryness, dysparenuia
Prevent osteoporosis
HRT is NOT prescribed to reduce the risk of __________
heart disease
Explain some of the risks of ERT and HRT
ERT: unopposed oestrogen- increased risk of developing endometrial and ovarian cancer
HRT: opposed oestrogen- increased risk of developing breast cancer
Increased risk of stroke and ischaemic heart disease
Increased risk of venous thromboembolism
What is clomiphene used for and how does it elicit its effect?
Induction of ovulation
Inhibits oestrogen binding in the anterior pituitary which inhibits negative feedback and therefore increased FSH and LH expression
What is the drug tamoxifen used for?
Reduces breast cancer risk
Induces ovulation
What is the drug mifepristone used for?
How does the drug produce this response?
Termination of pregnancy
Induction of labour
Makes the uterus more sensitive to prostaglandins
What are selective oestrogen receptor modulators (SERMs) and when might they be used?
e.g. Raloxifene
Drugs protect against osteoporosis
What is the drug finasteride used for?
Hair loss prevention - male pattern baldness
Benign prostatic hyperplasia
