A 24/4 OC regimen suppressed ovulation more effectively than did the traditional 21/7 regimen, even when the first three pills were missed.
Dosing errors are common in women who use oral contraceptives (OCs). Patients often fail to take the first few pills of a new pack, especially if their prescription plans cover only 1 month at a time. In a manufacturer-sponsored, double-blind study, researchers compared a conventional 21/7 OC regimen with a 24/4 regimen, with or without an intentional dosing error in each regimen. A total of 104 women (who were required to use nonhormonal contraception during the study) were randomized to receive two consecutive cycles of drospirenone (3 mg) plus ethinyl estradiol (20 μg) daily, either as 21 active pills followed by 7 inactive pills (21/7) or 24 active pills followed by 4 inactive pills (24/4). In the second cycle for each regimen, the firs…