Oral contraceptives

Abstract

Management of oral contraception requires an understanding of the relationships between the method's effectiveness, noncontraceptive benefits, and hormonal adverse effects. The new multiphasic combinations or OCs containing 35 micrograms of ethinyl estradiol and 0.5-1.0 mg of norethindrone or equivalent result in a maximum combination of efficacy and safety for the patient with minimal annoying problems for the patient and the prescriber. Patient education regarding early warning symptoms of adverse effects, breakthrough bleeding, and lack of withdrawal bleeding adds an additional margin of safety and reduces patient questions and uncertainties.

PIP: A review of the pharmacology of oral contraceptives is presented with emphasis on selection and management for primary care physicians. The paper is introduced with illustrations and diagrams of the menstrual cycle. Orals are 97-99.9% effective in the 1st year of use, which puts them between injectables and IUDs in efficacy, although failure rates are about 4.7% in women 21 years or less. The estrogens and progestins in current pills are described, and their biological effects defined. The actual estrogenic or androgenic effects of combined pills on different organs is complex, but often useful. All pills marketed in the U.S. from 1960-1987 are tabulated with their composition. Triphasic pills are currently popular, primarily because of marketing: they probably do have fewer systemic effects due to lower overall steroid doses. The generic pills now available are Norethin, NII and Genora, with norethindrone and ethinyl estradiol in 1.35 or 1.50 dosages. Contraindications are listed. Specific pills must be started according to packaging, usually with back-up contraception for the 1st cycle. Women must be taught the serious adverse effects to watch for: a mnemonic "ACHES" is suggested. Mortal risks of cardiovascular disease primarily affect women over 35 who smoke. Risks for older nonsmokers are similar to those of pregnancy. Pills present no known cancer risks; may uncover existing susceptibility to to diabetes; and reduce risk of pelvic infection. Management of spotting and of other minor side effects is described. Noncontraceptive benefits of oral contraceptives prevent estimates 50,000 hospitalizations and 1210 deaths per year in the U.S.