S5 L1 Sex Hormones Flashcards
What are three groups of drugs when considering sex hormones?
Why do drugs based on sex hormones take a while for a response?
They are steroid hormones so act through nuclear receptors so longer response
What are the actions and side effects of oestrogen?
What are the actions and side effects of progesterone?
What are the actions and side effects of testosterone?
What are the different routes of administration for sex steroid hormones?
- Oral
- Transdermal patch
- Implants
- Nasal
- Vagina
How are sex steroids transported in the blood?
- Transport bound to SHBG (except progesterone) and albumin
- SHBG production upregulated by oestrogens – protects against hepatic metabolism
What are some side effects of the combined pill?
- Thromboembolic disease (higher in obese, hypertensives, smokers, long term users and over 35)
- Mood swings
- Decreased glucose tolerance
- Mood swings
- Hypertension
How are sex hormone drugs metabolised and excreted?
- CYP450 in liver
- Metabolites are excreted in faeces and urine as glucuronides and sulphates, respectively
What is the mechanism of action for the COCP and POP?
COCP:
- Suppression of ovulation (inhibits FSH, LH)
- Thickens cervical mucus (more viscous)
- Prevents secretory phase in endometrium (remains atrophic)
POP: (low dose)
- Thicken cervical mucous
- Atrophy endometrium
- High dose implant stops ovulation but this doesn’t
- Need constant oestrogen as progestrone receptors only present when oestrogen around so not good if woman producing low oestrogen
What are some side effects of POP?
In the COCP, which progestins are prescribed?
- Medroxyprogesterone acetate
- Norethisterone
- Levonorgesterel
In the COCP, which oestrogens are prescribed?
ethinylestradiol
How are sex hormones synthesised?
From cholesterol
What drug-drug interactions can occur with the POP and COCP?
Metabolised by CYP450 so the following enzyme inducing drugs can lower the drugs response:
- Antiepileptics like carbamazepine and phenytoin
- Rifampicin and rifabutin
- St John’s Wort
- Soya protein for perimenopausal symptoms can enhance oestrogen absorption and reduce its storage in adipose so half life from 15 to 7 hours