RSSOral Contraceptives, Birth Control Pills
DRUG CLASS AND MECHANISM:
The combination birth control pills that contain estrogen and progestin are called monophasic, biphasic, or triphasic.
Monophasic birth control pills deliver the same amount of estrogen and progestin every day.
Biphasic birth control deliver the same amount of estrogen every day for the first 21 days of the cycle. During the first half of the cycle, the progestin/estrogen ratio is lower to allow the lining of the uterus (endometrium) to thicken as it normally does during the menstrual cycle. During the second half of the cycle, the progestin/estrogen ratio is higher to allow the normal shedding of the lining of the uterus to occur.
Triphasic birth control pills have constant or changing estrogen concentrations and varying progestin concentrations throughout the cycle. There is no evidence that bi- or tri-phasic oral contraceptives are superior to monophasic oral contraceptives, or vice-versa, in the prevention of pregnancy.
PRESCRIPTION: Yes
GENERIC AVAILABLE: Yes, for some (see below).
PREPARATIONS: Tablets, various amounts. (Please see the Birth Control article for non-oral contraceptives.)
STORAGE: All oral contraceptives should be stored between 15°C (59°F) and 30°C (86°F).
PRESCRIBED FOR: Birth control pills are prescribed to prevent pregnancy. When taken as directed, birth control pills fail in less than one in every 200 users over the first year of use.
Birth control pills also are prescribed to treat mid-cycle pain which some women experience with ovulation. Birth control pills, while regulating the menstrual cycle, reduce menstrual cramps and heavy bleeding, and, because of the reduced bleeding, they may prevent the anemia that can develop in some women. For this reason they also are sometimes prescribed for a number of conditions that are characterized by excessive bleeding or painful menses.
Doctors sometimes prescribe higher doses of birth control pills for use as a morning after pill to be taken up to 72 hours after unprotected intercourse to prevent fertilization and pregnancy.
DOSING: Many of the birth control pills come in easy to use dispensers in which the day of the week or a consecutive number (1, 2, 3, etc.) is written on the dispenser with a corresponding tablet for each day or number.
For example, some Ortho-Novum dispensers are labeled Sunday next to the first tablet. Thus, the first tablet is to be taken on the first Sunday after menstruation begins (the first Sunday following the first day of a woman’s period). If her period begins on Sunday, the first tablet should be taken on that day.
For birth control pills that use consecutive numbers, the first tablet (#1) is taken on the first day of the menstrual period (the first day of bleeding). Tablet #2 is taken on the second day, and so on.
Still other packages instruct women to begin on day five of the cycle. For such products, women count from day one of their menstrual cycle (day one is the first day of bleeding). On the fifth day, the first tablet is taken. Tablets then are taken daily.
Most birth control pills are packaged as 21-day or 28-day units. For 21-day packages, tablets are taken daily for 21 days. This is followed by a 7-day period during which no birth control pills are taken. Then the cycle repeats.
For the 28-day units, tablets containing medication are taken for 21 consecutive days, followed by a seven-day period during which placebo tablets (containing no medication) are taken.
Newer formulations with 24 days of hormone pills and only four days of placebo pills are now available, as are continuous or extended-cycle oral contraceptive regimens, in which only active hormone pills are taken. Extended-cycle preparations include 7-day intervals of placebo pills to be taken approximately every three months.
Women just starting to take birth control pills should use additional contraception for the first seven days of use because pregnancy may occur during this period.
If women forget to take tablets, pregnancy may result. If a single tablet is forgotten, it should be taken as soon as it is realized that it is forgotten. If more than one tablet is forgotten, the instructions that come with the packaging should be consulted, or a physician or pharmacist should be called.
DRUG INTERACTIONS: Estrogens can inhibit the metabolism (elimination) of cyclosporine, resulting in increased cyclosporine blood levels. Such increased blood levels can result in kidney and/or liver damage. If this combination cannot be avoided, cyclosporine concentrations can be monitored, and the dose of cyclosporine can be adjusted to assure that its blood levels do not become elevated.
Estrogens appear to increase the risk of liver disease in patients receiving dantrolene (Dantrium) through an unknown mechanism. Women over 35 years of age and those with a history of liver disease are especially at risk.
Estrogens increase the liver’s ability to manufacture clotting factors. Because of this, patients receiving warfarin (Coumadin) need to be monitored for loss of anticoagulant (blood thinning) effect if an estrogen is begun.
A number of medications, including some antibiotics and antiseizure medications, can decrease the blood levels of oral contraceptive hormones, but an actual decrease in the effectiveness of the oral contraceptive has not been convincingly proven. Nonetheless, because of this theoretical possibility, some physicians recommend back-up contraceptive methods during antibiotic use. Examples of medications that increase the elimination of estrogens include:
√ carbamazepine (Tegretol),
√ phenobarbital,
√ phenytoin (Dilantin),
√ primidone (Mysoline),
√ rifampin (Rifadin),
√ rifabutin (Mycobutin),
√ ritonavir (Norvir).
Birth control pills with higher concentrations of estrogen or alternative forms of contraception may be necessary in women using those medications.
PREGNANCY: Rarely, fetal abnormalities (including those of the vertebrae, anus, heart, trachea, esophagus, kidney, and limbs) have been reported (in about 7 per 10,000 cases of exposure during pregnancy to oral contraceptives), but the clear association with fetal abnormalities has not been firmly established. Modified development of the sexual organs occurs somewhat more frequently, in about three per 1000 cases of exposure. Specifically, masculinization of female infants has been reported with norethindrone and norethynodrel. Increased blood bilirubin concentrations and jaundice have been reported in infants born to women who took oral contraceptives shortly before and after conception.
NURSING MOTHERS: Use of birth control pills during lactation has been associated with decreased milk production, decreased infant weight gain, and decreased nitrogen and protein content of milk. The amount of estrogen consumed by an infant whose mother takes a standard dose of birth control pills is considered to be the same as from a lactating woman who is not taking birth control pills, and side effects have not been reported. Using a progestin-only product is most often recommended during lactation if birth control pills are to be used during this period. The American College of Obstetrics and Gynecology (ACOG) recommends delaying taking combined estrogen-progestin contraceptives until at least six weeks postpartum, while the World Health Organization (WHO) recommends delaying the initiation of combined contraceptives until six months.
SIDE EFFECTS: The most common side effects of the birth control pills include nausea, headache, breast tenderness, weight gain, irregular bleeding, and mood changes. These side effects often subside after a few months’ use. Scanty menstrual periods or breakthrough bleeding may occur, but are often temporary, and neither side effect is serious. Women with a history of migraines may notice an increase in migraine frequency. On the other hand, women whose migraines are triggered by fluctuations in their own hormone levels may notice improvement in migraines with oral contraceptive use because of the more uniform hormone levels during oral contraceptive use. Uncommonly, oral contraceptives may contribute to increased blood pressure, blood clots, heart attack, and stroke. Women who smoke, especially those over 35, and women with certain medical conditions, such as a history of blood clots or breast or endometrial cancer, may be advised against taking oral contraceptives, as these conditions can increase the adverse risks of oral contraceptives.
: This Article is about of Birth Control Pills also known as Oral Contraceptives, Oral contraceptives (birth control pills) are medications that prevent pregnancy. They are one method of birth control. Oral contraceptives ...
