Pharmacology of Hormonal Contraceptives Flashcards
Estrogen receptor mechanisms?
Steroid/lipophilic
Binds to receptor in cytoplasm
Leads to altered gene expression and mRNA synthesis
What is the most potent estrogen?
Estradiol
What are the most common synthetic forms?
Ethinyl estradiol and mestanol
Estradiol is not used because?
Poor oral bioavailability due to rapid first pass metabolism
Ester does what?
Allows longer duration of action
Estrogens cause what?
Proliferative changes in the endometrium and increase the amount of cervical mucus
Estrogen ADME
wide VofD Free drug is the active form Estradiol is eliminated rapidly but the synthetics are eliminated slower Into the urine Show enterohepatic re-circulation
Estrogen Adverse Effects
Increased risk of breast, endometrial, cervical, vaginal cancer
Increased risk of MI, DVT, or PE
Severe migraine, n/v, reactivation or exacerbate endometriosis
Pregnanes Example
Medroxyprogesterone acetate
Estranes Example
Nortestosterone
Estranes Properties
Exhibit progestational, androgenic (facial hair) and other activities
Gonanes Example
Norgestrel
Gonanes Properties
No estrogenic effects, diminished androgenic activity
Progestin activity on the reproductive tract development
Thickening of cervical mucous
Decrease progesterone at end of cycle –> menstruation
Progestin activity on CNS
Induce 0.6 degrees C –> depressant activity