Interchangeability of low-dose oral contraceptives. Are current bioequivalent testing measures adequate to ensure...

Current Food and Drug Administration guidelines for assessing the differences in bioavailability between generic oral contraceptives and brand-name products are inadequate to ensure therapeutic equivalence. The guidelines do not take into account those women who may have blood levels of active ingredients well outside the range of acceptability. Due to the narrow therapeutic range of steroids, these women may become pregnant or experience an increased incidence of breakthrough bleeding. Furthermore, oral contraceptive packaging is unique to each manufacturer, and any change in brands (and therefore packaging) can easily negate the sequential administration of the appropriate tablet. These are among the reasons proposed for placing oral contraceptives in the critical drug category, in which generic substitution and interchangeability of products should not be allowed.