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
Progestin activity on metabolic effects
Decreased effects of insulin, enhanced fat deposition
Progestin Receptor Mechanisms
Lipophilic
Receptors in the cell
Leads to altered gene expression and mRNA synthesis
Progestin ADME
Limited oral bioavailability due to hepatic metabolism
Broad distribution
In urine
Progestins bind to?
SHBG and albumin (plasma proteins)
Progestin adverse effects
Etopic pregnancy
Irregularm unpredictable spotting
Weight change
Abnormal glucose tolerance test
Monophasic
21 days with hormones + 7 without
Biphasic
Two different doses of hormones for 21 days
Triphasic
Three different doses of hormones for 21 days
Progestin only
Less effective
Needs to be taken at the SAME time every day
Irregular and unpredictable menstrual bleeding
Combination Oral Contraceptives
Progestin + Estrogen
Alters cervical mucous
Inhospitable endometrial lining
PREVENTS ovulation
Progestin in contraceptives?
Thicken cervical muculs
Slows sperm transport
Impairs implantation in the endometrium
Suppresses LH surge (ovulation)
Estrogen in contraceptives?
Stabilizes endometerial lining Suppresses FSH (prevents a dominant follicle)
Menstranol is?
50% less potent than ethinyl estradiol bc it has to be convert to it first
Extended cycle OCs
84 hormone pills +7 days of placebo
4 menstrual cycles per year
Continuous cycle OCs
Hormones for 21 days and then low-dose E&P for 4-7 days
Both extended and continuous cycle can lead to
Decreased amount of bleeding and ultimately amenorrhea
Side effects of OCs
N/V
MI, stroke, emboli
Breast enlargement
Breakthrough bleeding
Serious Side Effects of OCs?
Blood clots
ACHES
Cancer
Gall bladder
ACHES stands for
Abdominal pain Chest pain Headaches Eye problems Swelling and leg pain (DVT)
Precaution for use of COC
>35 Smoking HTN Dyslipidemia Diabetes Headaches Breast cancer Thromboembolism Obesity
Obesity problem?
The hormones will go hide in the fat cells of the body and not cause the effects they needed
