Current perspectives on combination oral contraceptives
Smith, M.A.; Youngkin, E.Q.
Clinical Pharmacy 3(5): 485-496
1984
ISSN/ISBN: 0278-2677 PMID: 6386284 Document Number: 238670
The physiology, mechanism of action, therapeutic use, effectiveness, potential risks, and noncontraceptive benefits of combination oral contraceptives (OCs) are reviewed with a discussion of patient considerations and management guidelines for common side effects. Modifications of the earlier combined (OCs) have both a lower estrogen and progestogen content. The contraceptive effects of estrogenic agents are related to modifications in ovulation, ovum transport, and implantation. The progestational agents act mainly by inhibiting ovulation and creating a hostile uterine environment. Biphasic and triphasic combined OCs are designed to deliver the hormones, throughout the menstrual cycle, in varying amounts that are similar to the natural physiologic quantities. Hte combined OC is the most effective method of birth control available with the exception of sterilization. If the low dose combined OCs are taken at approximately the same time each day, they are as effective as 50 mcg of estrogen in preventing pregnancy with a theoretical failure rate of less than .5/100 woman years. 3 longterm cohort studies of the risks of combined OC use are described. Although the primary focus of early research was on the adverse effects of combined OCs related to estrogen content, recent studies indicate that there are some noncontraceptive benefits associated with the use of the low dose combined OCs. In addition, the effects of progestogen content have been more closely examined in association with cardiovascular disease and metabolic effects. Guidelines for managing breadthrough bleeding and spotting, absence of withdrawal bleeding, nausea and vomiting, weight change, depression, and headaches are presented. Recommendations to be given to women who are beginning a combined OC regimen for the 1st time are outlined. Low dose combined OC given at the appropriate dose can provide relatively safe and very effective contraception for many women.