MOA. As contraceptives, estrogens suppress follicle-stimulating hormone (FSH) and luteinizing hormone (LH) to inhibit ovulation, cause edematous endometrial changes that are hostile to implantation of the fertilized ovum, accelerate ovum transport, and produce degeneration of the corpus luteum (luteolysis). Progestins inhibit ovulation by suppression of LH, inhibit sperm capacitation, slow ovum transport, produce a thinning endometrium that hampers implantation, and cause cervical mucus changes that are hostile to sperm migration.
Pharmacokinetics of Progestins
Drug Interactions: Oral Contraceptives
Adverse Reactions: Oral Contraceptives
Key Patient Counseling Points. Hormonal contraceptives do not protect against HIV infection or other sexually transmitted diseases. Take this drug at approximately the same time each day. If spotting occurs and no doses have been missed, continue to take tablets even if spotting continues. Report immediately if new severe or persistent headache; blurred or loss of vision; shortness of breath; severe leg, chest, or abdominal pain; or any abnormal vaginal bleeding occur. If you miss 1 dose, take it as soon as you remember it and take the next tablet at the correct time even if you take 2 tablets on the same day or at the same time. If you miss 2 doses in week 1 or 2, take 2 tablets on the day you remember and 2 tablets the next day. If you miss 2 doses in week 3 or miss 3 or more active tablets, then (if you start on day 1) start a new pack the same day or (if you start on Sunday) take 1 tablet daily until Sunday and then start a new pack that day. Use an alternative form of contraception for the next 7 days after you miss 2 or more doses in weeks 1, 2, or 3.
Clinical Pearls. Patients with thrombogenic mutations (eg, factor V Lieden) should not receive oral contraceptives. The CDC provides recommendations for choice of oral contraceptives on their web site at www.cdc.gov. Age, cigarette smoking, concurrent diseases, weight, drug interactions, and reproductive status are all considered when selecting a contraceptive regimen.