contraceptives Flashcards
Name the barrier techniques, their absolute contraindications, advantages and disadvantages
Male Condom:
- CI: allergy to latex/rubber
- Adv: protection against STI
- Disadv: high user failure rate, poor acceptance, possibility of breakage
Female Condom:
- CI: allergy to polyurethane, hx of toxic shock syndrome (TSS)
- Adv: can be inserted ahead of time, protection against STI if used correctly
- Disadv: very high user failure rate, dislike ring hanging outside vagina
Diaphragm with spermicide/ cervical cap:
- CI: allergy to latex/rubber/spermicide, recurrent UTIs, hx of TSS, abnormal gynaecologic anatomy
- Adv: low cost, reusable
- Disadv: high user failure rate, low protection against STI, increased risk of UTI, cerivical irritation
What conditions can oral contraceptives be used to manage?
Outline the mechanism of action of the estrogen and progestin componenets of combined oral contraceptives
estrogen: inhibits FSH secretion hence preventing the growth and maturation of the ovarian follicle; (+ stabilize the endometrial lining and provide cycle control)
progestin: inhibits LH surge hence preventing ovulation, thickens cervical mucus to prevent sperm penetration/delay sperm transport, induces endometrial atrophy
*progestins provide most of the contraceptive effect
Provide the doses of estrogen commonly used and the factors favouring their uses
Low dose estrogen: 20-25 mcg
- factors favouring use: weight < 50kg, adolescence, age > 35 years, peri-menopausal, has fewer side effects
High dose estrogen: 30-35 mcg
- factors favouring use: weight > 70.5kg / obesity, early-mid cycle breakthrough bleeding or spotting, if patient has the tendency to be non-adherent
Name the S/E of progestins and its absolute contraindications
- androgenic S/E (as progestins have inherent androgenic activity): acne, oily skin, hirsutism
- breast tenderness / weight gain
- newer generations of progestins (esp. drosperinone, cyproterone and desogestrel) increase risk of VTE when combined with estrogen
- specific S/E for drosperinone (anti-androgenic): hyperkalemia, thromboembolism, bone loss
CI:
- current breast cancer / recent history of breast cancer within the last 5 years
Name the S/E of estrogen and its absolute contraindications
S/E:
- bloating
- N/V
- breast tenderness/weight gain
- increased risk of breast cancer
- increased risk of endometrial cancer (if unopposed estrogen, e.g. in management of menopause)
- increased risk of venous thromboembolism (VTE), myocardial infarction (MI) / ischemic stroke
CI:
- current breast cancer, recent history of breast cancer within the past 5 years
- acute VTE/PE, history of VTE/PE, current VTE/PE and on anticoagulant therapy
- major surgery with prolonged immobilization
- <21 days postpartum + other risk factor
- < 6 weeks postparum if breastfeeding
- SLE with or unknown APLA
- migrane with aura
- severe hypertension (SBP>160 mmHg or DBP > 100 mmHg)
- hypertension + vascular disease
- current ischemic heart disease / history of ischemic heart disease
- cardiomyopathy
- smoking >= 15 sticks a day ANND age >= 35 years old
- history of cerebrovascular disease
- diabetes for > 20 years
- diabetes with complications
Name the risk factors for the development of venous thromboembolism (VTE) and myocardial infarction (MI) due to estrogen?
VTE:
age > 35 years old, obesity, smoking, immobilization, cancer, hereditary thrombopilla
MI:
age, obesity, smoking, pro-thrombotic mutations, dyslipidemia, hypertension, migraine with aura
for those with the above risk factors, to consider low-dose estrogen (20-25mcg), progestin-only contraceptive, or barrier methods
Provide the factors favouring the use for higher dose progestins?
late cycle breakthrough bleeding, painful menstrual cramps
Describe the different dosing regimes for the hormonal components in oral COCs?
Monophasic COC: same amounts of estrogen and progestin in every pill; pill-free interval of last 7 days of the cycle
Multiphasic COC: variable amounts of estrogen and progestin in every pill (tend to have lower overall progestin dose overall, hence less S/E)
Describe the different cycles for oral COCs?
Conventional cycle COC: 21 days active pill + 7 days of placebo / 24 days active pill + 4 days of placebo (newer formulations to shorten pill free interval to lessen S/E, such as headache)
Extended cycle COC: 84 days active pill + 7 days of placebo
Continuous cycle COC: active pill everyday (no placebo)
Describe how to initiate a COC and the backup contraceptive required?
First day of cycle start: no back up contraceptive required
First sunday of the cycle start: back up contraceptive required for at least 7 days
Start on any other day of the cycle: back up contraceptive required for at least 7 days and potentially until the next menstrual cycle begins
What are the common adverse effects of COC and how to manage them?
common adverse effects + management:
- Bloating; to reduce estrogen / change to progestin with mild diuretic effect
- N/V; to reduce estrogen / change to progestin only / take pills at night
- breast tenderness / weight gain: keep both estrogen and progestin as low as possible
- acne, oily skin, hirsutism: change to anti-androgenic progestin / if on progestin only pill, change to COC
- headache; usually occurs in the pill-free interval, hence switch to extended/continous cycle/shorter pill-free interval
- breakthrough bleeding; if early-mid cycle, to increase estrogen; if late cycle, to increase progestin
*these adverse effects tend to occur during early COC use and may improve by 3rd/4th cycle -> to counsel patients to persevere for 2-3 months before changing products unless there is a serious adverse effect (VTE/stroke/MI/migrane with aura etc.)
What are the drug interactions for COC?
Rifampicin (antibiotic); alters gut flora and metabolism of COC hence lowering the concentration of active drug; to use contraception for 7 days from the discontinuation of rifampicin
- in practice some providers might still recommend additional contraception when on anitbiotics in general
Anticonvulsants: they are CYP450 inducers, hence reduce serum free concentrations of both estrogen and progestin
- e.g. phenytoin, carbamazepine, barbituates, topiramate, oxcarbazepine, lamotrigine
HIV anti-retrovirals: they are CYP450 inducers, hence reduce serum free concentrations of both estrogen and progestin; efficacy of the retroviral is reduced as well due to the DDI
- e.g. ritonavir, darunavir
Describe the counselling information for missed dose of COC
if 1 missed dose (<48 h since last dose taken: take missed dose immediately and continue the rest as usual; no back-up contraceptive required
if >= 2 missed dose (>= 48 h since last dose taken): take 1 missed dose immediately, discard the rest of the missed doses, and continue the rest as usual; back up contraceptive required for at least 7 days
- if doses were missed during the placebo week (last week of cycle), can finish the remaining active pills and start a new pack right after (skip hormone free interval) ; back up contraceptive required for at least 7 days
Describe the dosing regime for progestin only pills (POP) / mini pills
norethindrone / levonorgestrel: 28 active pills
drospirenone: 24 active pills + 4 inactive pills
take at the same time everyday
Describe how to initiate a POP and the backup contraceptive required?
Start within first 5 days of cycle: no back up contraceptive required
Start on any other day of cycle: back up contraceptive required for 2 days (for norethindrone / levonorgestrel) or 7 days (for drosperinone)
Describe the counselling information for missed dose of POP?
norethindrone / levonorgestrel:
- if dose is late by > 3 hours, to take the missed dose immediately, and continue the rest as usual; back up contraceptive required for 2 days
drosperinone:
- if one missed dose (<48 h since last dose was taken), to take the missed dose immediately and continue the rest as usual; no back up contraceptive required
- if >= 2 missed dose (>= 48 h since last dose was taken), to take 1 missed dose immediately and discard the rest of the missed doses, continue the rest as usual; back up required for at least 7 days
Describe the dosing regime and S/E for transdermal contraceptive patches?
Apply once weekly for 3 weeks, followed by one patch free week
S/E: same as COC (bloating, N/V, breast tenderness, acne, headache, breakthrough bleeding) + application side reactions; potentially higher risk of VTE
*note that transdermal patches are less effective in patients > 90 kg
Describe the dosing regime and S/E for hormonal vaginal rings?
Use for 3 weeks then discard
S/E: same as COC (bloating, N/V, breast tenderness, acne, headache, breakthrough bleeding) + tissue irritation + risk of expulsion; potentially higher risk of VTE
Describe the dosing regime and S/E of progestin injections (Depo-Provera; depot medroxyprogesterone acetate, DMPA)?
IM injection every 12 weeks
S/E: same as COC (bloating, N/V, breast tenderness, acne, headache, breakthrough bleeding) + variable breakthrough bleeding esp in the first 9 months but will become amenorrheic after (most common S/E)
*weight gain (more than other types of contraceptives)
*also have loss of BMD; do not use for > 2 years, avoid in older women and in women who have other osteoporosis risk factors, e.g. on long term steroids
*note that return to fertility may be delayed after discontinuation (may be delayed for as long as 1.5 years)
name the contraindications for IUDs?
pregnancy, current STD, vaginal bleeding, malignancy of the genital tract, uterine abnormalities, uterine fibroids
describe the efficacy parameters and general risks for IUDs?
levonorgestrel IUD: effective for 5 years, ideal if concomitant menorrhagia as it causes a decrease in menstrual flow/amenorrhoea
copper IUD: effective for 10 years, ideal if concomitant amenorrhoea as it causes heavier menstrual flow, can be used as emergency contraception
effects reversible upon removal
general risks: uterine perforation, expulsion, pelvic infection
describe the efficacy parameters and S/E of subdermal progestin implants?
Subdermal progestin implant (4cm long implant, contains 68mg of etonogestrel): lasts for 3 years
S/E: irregular / variable bleeding pattern among patients, incl. amenorrhoea/prolonged bleeding/spotting/frequent bleeding
Describe the emergency contraception options available, including their efficacy rates (% pregnancy avoided), special considerations, dosing instructions and mechanism of action and key S/E
Copper IUD:
- > 99% efficacy
- insert within 5 days
- prevent sperm migration, damage ovum, damage/disrupt transport of fertilized ovum
Ulipristal 30mg (Ella tablet):
- 60-80% efficacy
- take one tablet ASAP, within 5 days
- progesterone receptor modulator, slows release of GnRH thus inhibiting ovulation and thinning endometrium lining
- do not give to patients who have taken progestin containing oral contraceptive in the past 5 days, and counsel to not take for the next 5 days after (will not be effective)
Levonorgestrel 0.75mg (Postinor 2 tablets):
- efficacy less than ulipristal
- take two tablets preferably within 12 hours, but no later than 72 hours (3 days)
- negative feedback of GnRH, slows release of GnRH, thus inhibiting ovulation and thinning endometrium lining
- less effective in obese patients
KEY S/E for all 3 emergency contraception: nausea -> to redose if vomit within 3 hours of taking tablet
