"What are birth control pills and how do they work?
Birth control pills are also known as oral contraceptives (OCs) or, simply, “the pill.” They offer protection against pregnancy by blocking the union of sperm and egg, thereby prevent"...
Oral contraceptives are indicated for the prevention of pregnancy in women who elect to use this product as a method of contraception.
Oral contraceptives are highly effective. Table 1 lists the typical accidental pregnancy rates for users of combination oral contraceptives and other methods of contraception.1 The efficacy of these contraceptive methods, except sterilization, depends upon the reliability with which they are used. Correct and consistent use of methods can result in lower failure rates.
Table I: Percentage of women experiencing an unintended pregnancy
during the first year of typical use and the first year of perfect use of contraception
and the percentage continuing use at the end of the first year. United States.
|Method||% of Women Experiencing an Unintended Pregnancy within the First Year of Use||% of Women Continuing Use at One Year3|
|Typical Use1||Perfect Use2|
|Copper T 380A||0.8||0.6||78|
|Norplant and Norplant-2||0.05||0.05||88|
| Emergency Contraceptive Pills: Treatment
initiated within 72 hours after unprotected intercourse reduces the risk
of pregnancy by at least 75%.9
Lactational Amenorrhea Method: LAM is a highly effective, temporary method of contraception.10
Source: Trussell J. Contraceptive Efficacy Table from Hatcher RA, Trussell J, Stewart F, Cates W, Stewart GK, Kowal D, Guest F, in Contraceptive Technology: Seventeenth Revised Edition. New York, NY: Irvington Publishers, 1998.
1 Among typical couples who initiate use of a method (not necessarily for the first time), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason.
2 Among couples who initiate use of a method (not necessarily for the first time) and who use it perfectly (both consistently and correctly), the percentage who experience an accidental pregnancy during the first year if they do not stop use for any other reason.
3 Among couples attempting to avoid pregnancy, the percentage who continue to use a method for one year.
4 The percents becoming pregnant in columns (2) and (3) are based on data from populations where contraception is not used and from women who cease using contraception in order to become pregnant. Among such populations, about 89% become pregnant within one year. This estimate was lowered slightly (to 85%) to represent the percent who would become pregnant within one year among women now relying on reversible methods of contraception if they abandoned contraception altogether.
5 Foams, creams, gels, vaginal suppositories, and vaginal film.
6Cervical mucus (ovulation) method supplemented by calendar in the pre-ovulatory and basal body temperature in the post-ovulatory phases.
7 With spermicidal cream or jelly.
8 Without spermicides.
9 The treatment schedule is one dose within 72 hours after unprotected intercourse and a second dose 12 hours after the first dose. The Food and Drug Administration has declared the following brands of oral contraceptives to be safe and effective for emergency contraception: Ovral (1 dose is 2 white pills), Aleese (1 dose is 5 pink pills), Nordette or Levlen (1 dose is 2 light-orange pills), Lo/Ovral (1 dose is 4 white pills), Triphasil or Tri-Levlen (1 dose is 4 yellow pills).
10 However, to maintain effective protection against pregnancy, another method of contraception must be used as soon as menstruation resumes, the frequency or duration of breastfeeds is reduced, bottle feeds are introduced, or the baby reaches six months of age.
DOSAGE AND ADMINISTRATION
To achieve maximum contraceptive effectiveness, oral contraceptives must be taken exactly as directed and at intervals not exceeding 24 hours.
28-Day Schedule: For a DAY 1 START, count the first day of menstrual flow as Day 1 and the first tablet (white or yellow-green or blue) is then taken on Day 1. For a SUNDAY START when menstrual flow begins on or before Sunday, the first tablet (white or yellow-green or blue) is taken on that day. With either a Day 1 START or SUNDAY START, 1 tablet (white or yellow-green or blue) is taken each day at the same time for 21 days. Then the orange tablets are taken for 7 days, whether bleeding has stopped or not. After all 28 tablets have been taken, whether bleeding has stopped or not, the same dosage schedule is repeated beginning on the following day.
Instructions To Patients
- To achieve maximum contraceptive effectiveness, the oral contraceptive pill must be taken exactly as directed and at intervals not exceeding 24 hours.
- Important: Women should be instructed to use an additional method of protection until after the first 7 days of administration in the initial cycle.
- Due to the normally increased risk of thromboembolism occurring postpartum, women should be instructed not to initiate treatment with oral contraceptives earlier than 4-6 weeks after a full-term delivery. If pregnancy is terminated in the first 12 weeks, the patient should be instructed to start oral contraceptives immediately or within 7 days. If pregnancy is terminated after 12 weeks, the patient should be instructed to start oral contraceptives after 2 weeks.33, 77
- If spotting or breakthrough bleeding should occur, the patient should continue the medication according to the schedule. Should spotting or breakthrough bleeding persist, the patient should notify her physician.
- If the patient misses 1 pill, she should be instructed to take it as soon as she remembers and then take the next pill at the regular time. The patient should be advised that missing a pill can cause spotting or light bleeding and that she may be a little sick to her stomach on the days she takes the missed pill with her regularly scheduled pill. If the patient has missed more than one pill, see DETAILED PATIENT LABELING: HOW TO TAKE THE PILL, WHAT TO DO IF YOU MISS PILLS.
- Use of oral contraceptives in the event of a missed menstrual period:
- If the patient has not adhered to the prescribed dosage regimen, the possibility of pregnancy should be considered after the first missed period and oral contraceptives should be withheld until pregnancy has been ruled out.
- If the patient has adhered to the prescribed regimen and misses 2 consecutive periods, pregnancy should be ruled out before continuing the contraceptive regimen.
Brevicon® (norethindrone and ethinyl estradiol tablets USP) are packaged in cartons of 3 tablet dispensers. Each dispenser contains 21 blue active tablets, round in shape with Watson debossed on one side and 254 on the other side and 7 orange inert tablets. The 7 orange inert tablets are round in shape with Watson debossed on one side and P1 on the other side.
Norinyl®1+35 (norethindrone and ethinyl estradiol tablets USP) are packaged in cartons of 3 and 6 tablet dispensers. Each dispenser contains 21 yellow-green active tablets, round in shape with Watson debossed on one side and 259 on the other side and 7 orange inert tablets. The 7 orange inert tablets are round in shape with Watson debossed on one side and P1 on the other side.
Norinyl®1+50 (norethindrone and mestranol tablets USP) are packaged in cartons of 3 and 6 tablet dispensers. Each dispenser contains 21 white active tablets, round in shape with Watson debossed on one side and 265 on the other side and 7 orange inert tablets. The 7 orange inert tablets are round in shape with Watson debossed on one side and P1 on the other side.
Store at controlled room temperature 15-25°C (59-77°F).
1. Trussell J. Contraceptive Efficacy Table from Hatcher R.A., Trussell J, Stewart F, Cates W, Stewart GK, Kowal D, Guest F, in Contraceptive Technology: Seventeenth Revised Edition. New York, NY: Irvington Publishers, 1998.
33. Mishell, D.R., et al.: Reproductive Endocrinology, Philadelphia, F.A. Davis Co., 1979.
77. Dickey, R.P.: Managing Contraceptive Pill Patients, Oklahoma, Creative Informatics Inc., 1984.
Address medical inquiries to: Watson Pharma, Inc., Medical Communications, P.O. Box 1953, Morristown, NJ 07962-1953. 800-272-5525. Distributed by: WATSON PHARMA, INC., A subsidiary of Watson Pharmaceuticals, Inc., Corona, CA 92880 USA. Manufactured by: Patheon, Inc., Mississauga, Ontario L5N 7K9, CANADA. FDA revision date: 8/15/2001
Last reviewed on RxList: 1/23/2009
This monograph has been modified to include the generic and brand name in many instances.
Additional Brevicon Information
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