Reproductive Pharmacology Flashcards
Name some GnRH agonists:
Buserelin; nafarelin
What are the functions of GnRH agonists?
Intermittent GnRH agonist administration stimulates LH and FSH release
Continuous GnRH agonist administration suppresses LH and FSH release. In IVF, its ‘down regulation’ action is to prevent a premature LH surge
Why must ED drugs NOT be used in patients taking nitrates?
Risk of life-threatening hypotension
Name some GnRH antagonists:
Cetrotide
What are the functions of GnRH antagonists?
Binds to pituitary GnRH receptors, preventing LH and FSH secretion, and thus reduces estrogen synthesis. In IVF, its ‘down regulation’ action is to prevent a premature LH surge
What are the S/E’s of GnRH antagonists?
Symptoms of oestrogen deficiency
Name some gonadotropin-modulating agents:
Goserelin; leuprolide
What are the functions of gonadotropin-modulating agents?
They act as a GnRH agonist when used in a pulsatile fashion, or an antagonist when used continuously (as when used for down regulation in IVF)
What is flutamide, and in whom is it used?
It is an anti-androgen, by acting as a competitive antagonist of the testosterone receptor
It may be used in prostate cancer
Alternatively, it may be used by women with hirsutism
What is finasteride, and in whom is it used?
It is an anti-androgen, by acting as a 5-alpha-reductase inhibitor. This results in a decrease in the conversion of testosterone to DHT
It may be used in BPH and male pattern baldness
Name some drugs used in ED:
Sildenafil; tadalafil
What is mechanism by which ED drugs work?
Inhibits cGMP PDE5. This increases cGMP availability. This results in vasodilation of vascular smooth muscle in the corpus cavernous, increasing blood flow for penile erection
What are ritodrine + salmeterol used for?
Prevention of premature labour in appropriately selected patients between weeks 22 and 33 gestation. They work by acting as beta-2-adrenergic agonists, blocking uterine contractions
In whom may ketoconazole and spironolactone be useful?
In those with hirsutism in PCOS due to their anti-androgen activity
What are the S/E’s of estrogen replacement?
Weight gain Breast tenderness Thrombosis Endometrial hyperplasia Increased risk of endometrial cancer Migraine
What is clomiphene used for, and how does it work?
Ovulation induction, in women with anovulatory infertility. It acts as a ER-antagonist at the hypothalamus, preventing negative feedback, resulting in increased GnRH, and therefore, increased FSH and LH. This results in an increase in ovulation
What are the S/E’s of clomiphene?
Multiple pregnancy
OHSS
Visual disturbance
What class of drug is Tamoxifen?
SERM - selective oestrogen receptive modulator. It acts as an agonist in endometrial tissue and bone, but an antagonist in breast tissue. It up regulates TGF-beta
In whom is Tamoxifen used?
HRT in women with a FHx of breast cancer
Estrogen-sensitive (ER +ve) breast cancers
Progesterone-reistant endometrial and ovarian cancers
Melanomas
Osteoporosis
How does Raloxifine differ from Tamoxifen?
Also a SERM, but has an antagonistic action in the endometrium (unlike Tamoxifen, which has an agonist effect in the endometrium)
In whom may progestins be used?
In those looking for a contraceptive - its suppresses ovulation
Alternatively it may be used to stimulate appetite in cachexic patients
What are the S/E’s of progestins?
Acne Hirsutism Fluid retention Weight change Depression Libido change Irregular menstrual cycle Breakthrough bleeding Increased BP Increased risk of DVT
