Birth Control Pills (Oral Contraceptives) (cont.)

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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 seven-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 backup contraceptive methods during antibiotic use. Examples of medications that increase the elimination of estrogens include



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