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Reproduction > Medicines in Reproductive Health > Flashcards

Medicines in Reproductive Health Flashcards

1
Q

What are the drug targets of hormones?

A

GnRH- acts on GnRH receptors
- Progesterone = progesterone receptors - Oestriol, oestrone, oestradiol = act on oestrogen receptors
- Dihydrotestsosterone and testosterone - act on testosterone receptors

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2
Q

What are the classes of drugs in reproductive health?

A

-GnRH agonists and antagonists
- Oestrogens agonist, antagonists and modulators
- Progestogen agonists and antagonists
- Androgen agonists and antagonists
- 5-a reductase inhibitors
- Aromatase inhibitors
- Combinations

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3
Q

What are the receptors dor steroid hormones?

A
  • Called cytoplasmic or nuclear receptors
  • Steroids can pass through the cell membrane
  • Acticvated receptors regulate gene transcription. Ligand - activated transcription factors
  • ## May recruit co-activator molecules
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4
Q

What are the routes of administration for steroids?

A
  • Steroids = quite lipophilic so they can reach their receptors )
  • Can be applied topically, Nasal spray, patches
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5
Q

What are transdermal patches?

A

Advantages :

  • Avoids first pass metabolism
  • Better bioavailabilty
  • Stable concentrations
  • Better compliance

Disadvantages :
- Can get skin reactions/irritation
- Might fall off

Transdermal patch design - layers:
1.) Impermeable backing
2.) Reservoir for drug dissolved in liquid or gel or solid polymer matrix
3.) Semi-permeable membrane
4.) Adhesive layer

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6
Q

What is the intramuscular injection of esters?

A
  • The hormone is esterified with, i.e., Valerate, cypionate - more lipophilic
  • Prodrug - once absorbed the ester group is enzymatically removed
  • CH - hyrdocarbons - oil/fats. Making it more lipophilic
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7
Q

What are the roles of oestrogen?

A
  • Normal sexual maturation and growth of the female (uterine and breast growth)
  • Endometrial hyperplasia
  • Increased bone mass
  • Increased triglycerides and HDL and decrease in total serum cholesterol, LDL
  • Decrease in atherogenesis and increase in vasodilation
  • Increase in clottting and increased risk of thromboembolism
  • Increased water retention
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8
Q

What are the oestrogen receptors?

A

Two main types:
- ERa and ERB
- Form dimers, aa,ab and BB
- Signalling can be direct genomic or indirect genomic = complexity
- Present in many organs and tissues
- SOme modulators work in only breast/ bone tussue

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9
Q

What are oestrogen agonists (analogues) ?

A
  • Oestrogens undergo enterohepatic cycling = the movement of bile acid from the liver to the small intestine and back to the liver

What is the significance of this for oral compared with transdermal administration?
- The inetraction of broad-spectrum antibiotics with oral contraceptives was previously thought to involve enterohepatic cycling but this is now somewhat controversial.

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10
Q

What are some clinical uses of oestrogen?

A

Replacement therapy:
* Primary hypogonadism — stimulate development of secondary sexual characteristics

  • At or after menopause prevent menopausal symptoms (flushing, vaginal dryness, protect against osteoporosis)
  • Contraception
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11
Q

What are some adverse effects of oestrogen agonists?

A
  • tenderness in breasts
  • endometrial hyperplasia
  • risk of thromboembolism
  • Retention of salt and water = oedema
  • Migraines, hyperpigmentation, uterine bleeding (postmenopausal)
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12
Q

What is the link between oestrogen and breast cancer?

A

Many breast cancers are responsive to oestrogen — that is, there are oestrogen receptors on breast cancer cells and activation causes growth of the cancer cells.
Tamoxifen was originally developed as an antagonist at oestrogen receptors to treat breast cancer.

However, whilst tamoxifen can reduce growth of breast cancer cells, it does not appear to cause osteoporosis.
- “antagonist” raloxifene can be used to treat both breast cancer and prevent osteoporosis.

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13
Q

What are selective oestrogen receptor modulators (SERMs)?

A
  • drugs that can be agonists in some tissues, partial agonists in others and antagonists in others
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14
Q

What is clomiphene?

A
  • Oestrogen antagonists that induces ovultaion
  • Antagonist in the hypothalamus and anterior pituitary gland, partial agonist in the ovaries
  • Blocks oestrogen in pituitary - relief of negative feedback inhibition- increased release of GnRH and gonadotropins
  • Increase in FSH - stimulate follicle growth- oestrogen trigger signal- LH surge - ovulation
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15
Q

What are progesterone receptors?

A
  • PR-A and PR-B recpetors
  • Inactive receptors is in nucleus
  • Activation - PRE ( Progesterone Response Elements) - altered gene transcription
  • Some effects are transcription independent
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15
Q

What are the roles of progesterone?

A
  • GnRH suppression
  • Decreases oestrogen stimulated endometrial proliferation
  • Increased viscosity of cervical mucus
  • Fat and carbohdyrate metabolism
  • Decrease Na+ reabsorption
  • Development of breast and endometrium
16
Q

What are clinical uses of progesterone?

A
  • Contraception
  • With oestrogen in combined oral contraceptive pill
  • Progesterone-only
  • Injectable or implantable progesterone-only contraception
  • Part of intrauterine contraceptive system
  • HRT - combined with oestrogen
  • Long-term ovarian supression (resulting in prolonged anovulation and amenorrhea
  • Endometriosis
  • Endometrial carcinoma
17
Q

What are the adverse actions of progesterone agonists ?

A

Weak androgenic actions (see next section)
Acne
Fluid retention
Weight change
Depression
Change in libido
Breast discomfort
Irregular menstrual cycles and breakthrough bleeding
Increased risk of thromboembolism

18
Q

What are progesterone antagonists?

A
  • Mifepristone
  • Competitive anatagonist but may have some partial agonist activity
  • Used for medical termination of pregncnay (given with a prostaglandin (e.g. gemeprost)
  • Caution : has anti-glucocortucoid activity so not to be used in women taking glucocorticoids

*

19
Q

What are the androgen receptors?

A
  • Testosterone - recpetor = AR
  • Nuclear receptor
  • Inactive receptor in cytoplasm, activated receptor translocates to nucleus - modifies gene transcription
  • Testosterone is metabolised to oestrogen by aromatase and some effects result from action of oestrogen
20
Q

What are the roles of testosterone?

A

Testosterone
Converted to dihydrotestosterone = active metabolite
Spermatogenesis in Sertoli cells.
Maturation of spermatozoa as they pass through the epididymis and vas deferens.
Feedback on the anterior pituitary, modulating its sensitivity to GnRH and thus influencing secretion of LH/ICSH.
Metabolic actions (anabolic agents — muscle, bone; sebum production)
Haematological actions ( Increases production of erythropoietin)

21
Q
A
21
Q

What are testosterone agonists?

A
  • testosterone given via subcutaneous implant or transdermal patch since there is significant first pass metabolism
  • Esters of testosterone ( testosterone proprionate) - intramuscular depot injections
22
Q

What are some clinical uses of testosterone?

A
  • Hormone replacement :
  • Male hypogonadism (pituitary or testicular disease)
  • Female hyposexuality following ovariectomy
  • Illicit use of anabolic steroids (nandrolone, oxymetholone)
22
Q

What are the adverse effects of testosterone?

A

Doses of testosterone that mimic endogenous levels have no more side effects than endogenously secreted testosterone.
However, excessive doses can lead to prostate cancer, sodium retention (oedema, hypertension)
Use of illicit anabolic steroids can lead to:
Decreased testicular size
Diminished fertility
Erythrocytosis
Gynecomastia
Liver damage

23
Q

What are androgen antagonists and what are their clinical uses?

A

Androgen Antagonists
Flutamide, cyproterone — block actions of testosterone and
dihydrotestosterone.
Clinical uses:
Prostate cancer (flutamide, enzalutamide, bicalutamide)
Hirsutism (spironolactone)
Progestogen in some oestrogen-progestogen contraceptives (drospirenone)
“Chemical castration” in male sexual offenders (cyproterone acetate)
Hyperandrogenisation in females (cyproterone acetate)

24
Q

What are selective androgen receptor modulators (SARMs)?

A

Selective Androgen Receptor Modulators (SARMs)
One in clinical phase, more being developed
Potential clinical uses muscle-wasting disorders, Duchenne
muscular dystrophy, stress urinary incontinence, osteoporosis,
breast cancer
Sold as supplement in 2013 (LGD-4033, illegal)

25
Q

What do enzyme inhibitors of aromatase prevent?

A
  • Prevent the metabolism of testosterone and androstenedione to oestrogens
  • Beneficial in breast cancers that are stimulated by oestrogen
  • Menopausal side effects result due to lack of oestrogen
26
Q

What is the role of GnRH in inhibition>

A
  • when given in pulses, it can mimic physiological secretion of GnRH, which stimulate gonadotrophin release and induces ovulation
  • It is possible to suppress the Hypothalamic-pituitary- gondal axis either by continuous administration of a GnRH agonist or by administration of a GnRH receptor antagonist
27
Q

What are GnRH agonists?

A

Synthetic GnRH is termed gonadorelin
* Goserelin and other GnRH agonists have longer half lives
*Continuous use, by nasal spray or as depot preparations, transiently stimulates then inhibits gonadotrophin release because of downregulation (desensitisation) of GnRH receptors in the pituitary.

  • cause gonadal suppression, used in
  • prostate and breast cancers,
  • endometriosis
    large uterine fibroids.

May lead to :
- typical symptoms of menopause
- Reduced bone densiry and osteoporosis
- Signs and symptoms of androgen deprivation

Reproduction (22 decks)

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