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Does St. John's wort interfere with the antiandrogenic effect of oral contraceptive pills?
Robin H Fogle1, Patricia A Murphy, Carolyn L Westhoff
1Department of Obstetrics and Gynecology, Division of Reproductive Endocrinology and Infertility, Women's and Children's Hospital, University of Southern California, Keck School of Medicine, Los Angeles, CA 90033, USA. robinfogel@yahoo.com
Background:
St. 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 Methods:
Fifteen healthy women were treated with the low-dose OC Loestrin 1/20trade mark 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.
Results:
There were no statistically significant differences in androgen levels after the addition of SJW in women using Loestrin 1/20trade mark. 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%).
Conclusions:
In women using OCPs and SJW simultaneously, it appears that SJW does not interfere with the antiandrogenic properties of OCPs.
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