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CMT-tres > Hormonal Contraceptives > Flashcards

Hormonal Contraceptives Flashcards

1
Q

Hormonal Contraceptives (HCs)

General

A

Contain synthetic analogs of the reproductive hormones (estrogen and/or progesterone)
Act synergistically to produce anti-ovulatory effects
Suppression of GnRH

Affect the endometrial lining (↓ bleeding and pain associated with menstruation)

Available formulations:
Oral contraceptive pills (combined and progestin-only)
Transdermal patches
Vaginal rings
Progestin injections
Subdermal implants
Intrauterine devices

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2
Q

Choice of Contraception

A

The choice of contraceptive method is individualized and often is dictated by a variety of factors:

Ease of access and use (dosing regimen, required procedures)
Affordability
Efficacy rate
Reversibility or permanence
Prevention of STIs
Adverse effects
Medical contraindications
Ethical and moral beliefs

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3
Q

Chemistry review

Ethinyl estradiol (EE)

A

Both estrogens and progestins are steroidhormones, making them fat-soluble and highly protein-bound

Ethinyl estradiol (EE):
Very similar in structure to natural estradiol
Addition of an ethynyl group (C2H) makes it significantly more stable than estradiol
↑bioavailability as compared with estradiol when taken orally
~50% (natural estradiolis only ~5%)
Only estrogen used in hormonal contraception (variable doses)

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4
Q

chemsirty review

progestins

A

Progestins:
Similar in structure to progesterone
Addition of a triple bond in most cases makes the molecules more stable

Androgenic effects:
Most are derived from testosterone → have stronger androgenic effects than natural progesterone
Less androgenic: norgestimate, etonogestrel, and desogestrel
Antiandrogenic activity: drospirenone (spironolactone analog)

Multiple different progestins are used in HCs → different properties of the progestins are responsible for different side-effect profiles of various HCs

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5
Q

Normal Physiology of theMenstrual Cycle

HPO axis

Understanding hormonal regulation of ovulation and themenstrual cycleis key to understanding the mechanisms of hormonal contraceptives

A

HPO axis:
Hypothalamussecretes gonadotropin-releasing hormone (GnRH)
Pituitary secretes:
Follicle-stimulating hormone (FSH)
Luteinizing hormone (LH)
Ovary secretes:
Estrogen
Progesterone

Menstrual cycle regulation is primarily by the hypothalamic-pituitary-ovarian (HPO) axis

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6
Q

Normal Physiology of theMenstrual Cycle

Follicular/Proliferative phase

A

Follicular/Proliferative phase:
GnRH pulse stimulates the release of FSH

FSH stimulates follicular development within theovaries
Developing follicles produce estrogen (estradiol)

Estrogen:
Stimulates endometrial proliferation
Inhibits FSH secretion (feedback inhibition)

Ovulation:
Triggered by a midcycle surge of LH

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7
Q

Normal Physiology of theMenstrual Cycle

Luteal/Secretory phase

A

Luteal/Secretory phase:
The ovulated follicle is now called the corpus luteum
The corpus luteum produces progesterone and a moderate amount of estrogen

Progesterone:
Stabilizes endometrium
Causes endometrium to mature into secretory endometrium, capable of sustaining apregnancy
Progesterone = “progestational hormone” → produced only after ovulation, when gestation is possible
If pregnant: corpus luteum continues producing progesterone until theplacentacan take over
If not pregnant: corpus luteum involutes → estradiol and progesterone levels fall

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8
Q

Normal Physiology of theMenstrual Cycle

menstrual phase

A

Menstrual phase:
Loss of stabilizing hormones (particularly progesterone) triggers breakdown of the endometrium → menses
Key point: Progesterone withdrawal triggers bleeding

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9
Q

Mechanism of Action of Hormonal Contraceptives

Estrogen

A

Both estrogens and progestins cause an antiovulatory effect
Used together, this effect is SYNERGISTIC

Estrogen component:
Inhibits FSH release → prevents the selection and maturation of the dominant follicle = No ovulation

Stimulates endometrial proliferation if given without progestin (↑ a patient’s risk for certain cancers) → ethinyl estradiol is NOT given alone

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10
Q

Mechanism of Action of Hormonal Contraceptives

Progestin

A

Progestin component:
Inhibits LH surge that is necessary for ovulation by decreasing the pulse frequency of the GnRH

Effects on the endometrium:
Natural progesterone is required to make the endometrium healthy forpregnancy
Androgenic nature of synthetic progestins thins the endometrial lining, making it unsuitable for implantation
All hormonal contraceptives are “progestin-dominant” → overall endometrial effect of hormonal contraceptives is endometrial atrophy

↑ Cervical mucus viscosity → inhibits sperm transport into the uterus

↓ Cilia motility in the fallopian tube

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11
Q

Classification of Hormonal Contraceptives

A

Grouped by the length of their action and route of administration
Short-acting contraceptives
Includes pills, patches, rings, and injections
Long-acting reversible contraceptives (LARCs)
Emergency contraception

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12
Q

Short-acting contraceptives

Combined Oral Contraceptive Pills (COCPs)

A

Classified by the number of “phases”:
Monophasic: Each pill contains fixed amounts of ethinyl estradiol and progestin
Biphasic: Variable amounts of ethinyl estradiol and a form progestin
Triphasic: Variable amounts of ethinyl estradiol and a form progestin

Low-dose ethinyl estradiol (10-35 mcg) preferred to high-dose (50 mcg)
Daily administration

Initiation on the first day of the menstrual cycle or first Sunday after the onset of the cycle
NOTE: Patients using the first Sunday start are not protected from pregnancy in the first 7 days and an additional form of birth control will be needed
Pregnancy rate
0.3% with perfect use
8% with typical use

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13
Q

Combined Oral Contraceptive Pills (COCPs)

Non-contraceptive benefits:

A

More regular, lighter, shorter menses
Improvement of dysmenorrhea symptoms (cramping)
Decreased risk of ovarian, endometrial, and colon cancers
Improvement of acne and unwanted hair growth
Functional ovarian cysts are less likely
Lower frequency of uterine myomas with taking COCPs > 4 years
Reduce the frequency of migraines associated with menstruation (NOT for use in patients with migraines with aura)

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14
Q

Transdermal patch

A

Small, square adhesive patch worn on the skin
Buttocks, chest (not the breasts), upper back or arm, or abdomen
Releases ethinyl estradiol and norelgestromin or levonorgestrel daily which is absorbed through the skin
Hormone blood levels are more constant with the patch than with OCs

Weekly administration
1 patch applied per week for 3 weeks in a row
Rotate application sites
No patch applied for 7 days…menses occurs
Less effective in women > 90 kg

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15
Q

Vaginal ring

A

Flexible, transparent, plastic ring that is placed in the upper vagina
Releases ethinyl estradiol and a progestin (etonorgestrel = NuvaRing; segesterone = Annovera) that is absorbed through the vaginal tissues

Ring types
Month-long (NuvaRing)
1 ring inserted for 3 weeks/21 days; removed for 7 days…menses occurs
Replaced each month

Year-long (Annovera)
1 ring inserted for 3 weeks/21 days; removed for 7 days…menses occurs
Replaced once a year

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16
Q

Methods of Administration

Cyclic administration

A

Cyclic administration:
Pills/patches/rings containinghormonesare typically used for 21–24 days in a row (ovulation and endometrial growth are suppressed during this time)
Hormone-free interval (HFI):
Typically 4–7 days in length
Pill packs include placebo pills
Patch/ring is withheld during this time
Withdrawal bleeding during this time

17
Q

methods of administration

prolonged cyclic/ continuous administration

A

Prolonged cyclic administration:
Hormones taken for up to 84 days (12 weeks) followed by a 4–7-day HFI
Withdrawal bleeding typically 4 times per year
Hormone use can be extended beyond 12 weeks if tolerated by the patient

Continuous administration:
Hormones are taken continuously, with no HFI
Monophasic pills, the patch, and vaginal ring can all be administered this way
Higher risk of breakthrough bleeding owing to prolonged endometrial atrophy

18
Q

Progestin-only pills (POPs)

A

Commonly called “mini pills”
Daily administration at the same time every day
Packs of 28 active pills
Packs of 24 active pills and 4 inactive pills
Can be inconsistent in preventing ovulation
Hormone: norethindrone or drospirenone
Pregnancy rate
0.3% with perfect use
9% with typical use

19
Q

Progestin injections

A

Sightly more effective than progestin-only pills
“Quarterly” administration by an OB/GYN
1 injection (IM or SC) every 3 months or 13 weeks
Can be given up to 2 weeks late (15 weeks from the last injection)
Hormones: depot medroxyprogesterone acetate (DMPA)

In the 3 months after the first injection
30% have amenorrhea
30% have spotting or irregular bleeding
After 2 years, ~70% have amenorrhea
Pregnancy rate
0.2% with perfect use
6% with typical use

Takes an average of 10 months to conceive following discontinuation of the injections

20
Q

Long-acting reversible contraceptives (LARCs)

Subdermal contraceptive implant

A

4 cm, single-rod implant inserted through a trocar subdermally in the upper arm

Releases etonogestrel at a rate of 50 mcg/day to prevent ovulation, thicken cervical mucus, and thin the uterine lining

Lasts 3 years

21
Q

LARCs

Intrauterine device (IUD)

A

T-shaped, plastic device that is inserted into and left inside the uterus
Works to prevent fertilization by thickening cervical mucus and thinning the uterine lining

Includes:
Copper IUD (ParaGard)
Lasts 10 years

Hormonal IUD
levonorgestrel
Mirena & Liletta(52 mg of levonorgestrel): last 7 years - Mirena and 6 years - Liletta
Kyleena(19.5 mg of levonorgestrel): lasts 5 years
Skyla(13.5 mg of levonorgestrel): lasts 3 years

22
Q

Emergency contraception (EC)

A

Contraception administered after unprotected intercourse (UPI) or if birth control fails
♀ with regular menses and a single act of intercourse → 5% risk of pregnancy
♀ with irregular menses and a single act of intercourse → 12-20% risk of pregnancy

Acts to preventfertilizationand/or implantation

Commonly used emergency contraception regimens:
Insertion of a copper IUD
Insertion of a levonorgestrel 52 mcg IUD
Oral regimens

23
Q

Emergency contraception

Insertion of an IUD:

A

Provide ongoing contraception
Not impacted by body mass index or risk ofpregnancy(UPI midcycle, multiple episodes of UPI)
Options:
Copper IUD
More effective than oral methods
Pregnancy rate is 0.1%
Levonorgestrel 52-mg IUD

24
Q

emergency contraception

Oral methods - “the morning after pill”

A

Less effective in individuals with BMI > 30
Less effective in individuals at higher risk ofpregnancy (when UPI occurs)

Options:
Taken as a single course as soon as possible after UPI
Ulipristal acetate 30 mg PO once (can be used up to 5 days after UPI)
Oral levonorgestrel 1.5 mg PO once (can be used up to 3 days after UPI)
Combined EC pills taken at higher doses than normal as soon as possible after UPI (often causes nausea and vomiting)

Time in the menstrual cycle that EC is administered and the patient’s BMI are major factors in the likelihood of pregnancy!

25
Q

Adverse Effects of Hormonal Contraception

A

Risk of venous thromboembolism (VTE):
↑ risk with ethinyl estradiol > progestins and is dose dependent
Ethinylestradiolshould be avoided in people at risk for VTE
Progestin-only methods are recommended

Abnormal bleeding (unscheduled bleeding (spotting), prolonged bleeding)
More often associated with progestin-only methods
Estrogen tends to stabilize bleeding patterns
Worst with etonogestrel implant

Ovarian cysts
Associated with progestin-only methods
Ethinyl estradiol generally suppresses cyst formation

Breast symptoms:
Fibrocystic breast changes
Mastalgia (breastpain)
Decreased breast milk production during breastfeeding(ethinyl estradiol only)

Weight gain
Progestin injections
Average < 5 pounds
Due to changes in appetite rather than metabolism

Nausea/vomiting
Headaches/migraines
Decreased libido
Melasma

26
Q

Unique Adverse Effects

A

Vaginal ring: ↑ vaginal discharge
depot medroxyprogesterone acetate (DMPA) injections:boneloss (reversible)

IUDs:
Pelvicpain
Endometritis
Uterine perforation
Device expulsion: copper IUD > hormonal IUD
Ifpregnancyoccurs, significantly ↑ risk of thatpregnancybeing ectopic (though the absolute rate ofectopic pregnancyis lower in IUD users than in individuals on no contraception)

27
Q

Drug interactions

A

Metabolism of COCPs and POPs is increased by any drugs that increaselivermicrosomal enzyme activity, resulting in reduced contraceptive efficacy

Anticonvulsants:
Phenytoin
Carbamazepine
Barbiturates
Topiramate
Felbamate
Oxcarbazepine
Lamotrigine (HC ↓ lamotrigine levels and affect seizure control)

Antimicrobials:
Rifampin
Rifabutin
The vast majority of antibiotics do not interact with HCs

Antiretroviral drugs
Non-nucleoside reverse transcriptase inhibitors
Protease inhibitors

CMT-tres (53 decks)

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