Does St. John's wort interfere with the antiandrogenic effect of oral contraceptive pills?

BackgroundSt. John's wort (SJW), a commonly used herbal remedy, has been shown to compromise the efficacy of drugs, including oral contraceptive pills (OCPs), by inducing cytochrome P-450. We investigated whether the simultaneous use of SJW with OCPs resulted in elevated serum androgen levels with implications of impaired OCP treatment of hirsutism and acne.Materials and MethodsFifteen healthy women were treated with the low-dose OC Loestrin 1/20™ for 2 months and then additionally with SJW for 2 months. Androgen and sex hormone-binding globulin (SHBG) levels were measured in serum by immunoassay methods; free testosterone (fT) was calculated. Results were analyzed using the Wilcoxon signed-rank test.ResultsThere were no statistically significant differences in androgen levels after the addition of SJW in women using Loestrin 1/20™. However, there were decreases in total testosterone and fT levels (10.7% and 15.8%, respectively) along with a small increase in SHBG levels (7.0%).ConclusionsIn women using OCPs and SJW simultaneously, it appears that SJW does not interfere with the antiandrogenic properties of OCPs.