Topiramate does not completely eliminate the effect of oral contraceptives, but may decrease yours contraceptive efficacy.
Topiramate may reduce the concentration of the contraceptive in the bloodstream and, consequently, decrease the effectiveness and protection of contraception. Therefore, depending on the dosage of topiramate used, the doctor should consider the use of another contraceptive method (non-hormonal) additional.
The use of topiramate combined with oral contraceptives may increase the escape bleed. This is not indicative of low effectiveness of the contraceptive.
The woman should inform the doctor who prescribed her topiramate that she uses oral contraceptives and also inform her if she presents any changes in her menstrual patterns.