From the Guidelines
Yes, there are contraindications to using topiramate with oral contraceptives, as topiramate can reduce the effectiveness of hormonal contraceptives by increasing their metabolism through enzyme induction, potentially leading to contraceptive failure and unintended pregnancy. According to the most recent guidelines, women taking topiramate should use a hormonal contraceptive containing at least 35 mcg of ethinyl estradiol or consider alternative contraceptive methods 1. The interaction occurs because topiramate induces cytochrome P450 enzymes in the liver, which accelerates the breakdown of contraceptive hormones. This effect is dose-dependent, with higher doses of topiramate (200 mg daily or more) causing more significant interactions. Women should be advised that breakthrough bleeding may be a sign of reduced contraceptive effectiveness. If topiramate treatment is initiated or discontinued while on hormonal contraceptives, patients should be monitored for changes in seizure control or migraine frequency, as well as for signs of contraceptive failure.
Some key points to consider:
- Topiramate can reduce the efficacy of the contraceptive pill/oral contraceptives and other hormonal contraceptives 2
- Women must be informed of the potential interaction between topiramate and hormonal contraceptives 2
- Alternative contraceptive methods should be considered for women taking topiramate 3, 4, 1
- The interaction between topiramate and hormonal contraceptives is most significant with low-dose oral contraceptives (containing less than 35 mcg of ethinyl estradiol) 3, 4
It is essential to prioritize the patient's morbidity, mortality, and quality of life when making decisions about contraceptive use and topiramate therapy. Therefore, women taking topiramate should use a hormonal contraceptive containing at least 35 mcg of ethinyl estradiol or consider alternative contraceptive methods.
From the FDA Drug Label
Oral Contraceptives: In a pharmacokinetic interaction study in healthy volunteers with a concomitantly administered combination oral contraceptive product containing 1 mg norethindrone (NET) plus 35 mcg ethinyl estradiol (EE), Topiramate given in the absence of other medications at doses of 50 to 200 mg/day was not associated with statistically significant changes in mean exposure (AUC) to either component of the oral contraceptive. In another study, exposure to EE was statistically significantly decreased at doses of 200, 400, and 800 mg/day (18%, 21%, and 30%, respectively) when given as adjunctive therapy in patients taking valproic acid. In both studies, Topiramate (50 mg/day to 800 mg/day) did not significantly affect exposure to NET Although there was a dose dependent decrease in EE exposure for doses between 200 to 800 mg/day, there was no significant dose dependent change in EE exposure for doses of 50 to 200 mg/day. The clinical significance of the changes observed is not known The possibility of decreased contraceptive efficacy and increased breakthrough bleeding should be considered in patients taking combination oral contraceptive products with Topiramate. Patients taking estrogen containing contraceptives should be asked to report any change in their bleeding patterns. Contraceptive efficacy can be decreased even in the absence of breakthrough bleeding
The use of topiramate with oral contraceptives is not strictly contraindicated, but it may be associated with decreased contraceptive efficacy and increased breakthrough bleeding. Patients taking estrogen-containing contraceptives should be monitored for changes in their bleeding patterns. The clinical significance of the changes observed is not known, and the possibility of decreased contraceptive efficacy should be considered, especially at higher doses of topiramate 5. Key points to consider:
- Decreased exposure to ethinyl estradiol (EE) at higher doses of topiramate
- No significant effect on exposure to norethindrone (NET)
- Possibility of decreased contraceptive efficacy and increased breakthrough bleeding
- Patients should be monitored for changes in bleeding patterns
From the Research
Contraindications of Topiramate with Oral Contraceptives
- The use of topiramate with oral contraceptives may lead to decreased effectiveness of the contraceptive due to the potential interaction between the two medications 6, 7.
- Studies have shown that topiramate can decrease the area under the concentration-versus-time curve (AUC) of ethinyl estradiol, a component of oral contraceptives, by 18-30% 6.
- However, other studies have found that low-dose topiramate (≤200 mg/d) may not significantly influence oral contraceptive effectiveness 8, 7.
- It is recommended that clinicians consider initial therapy with an oral contraceptive containing ≥35 μg of ethinyl estradiol when prescribing for patients receiving topiramate 6.
Alternative Contraceptive Methods
- Long-acting reversible contraceptive (LARC) methods, such as intrauterine devices (IUDs) and implants, may be a suitable alternative for women taking topiramate 9.
- These methods provide high contraceptive effectiveness with a single intervention and can be used for an extended period 9.
- Pharmacists can assist patients in selecting a suitable contraceptive method based on their personal situation and lifestyle 10.