Oral Contraceptives and St Johns Wort

Oral contraceptives are divided into two types: progestogen only and combined estrogen and progestogen. Most oral contraceptives are substrates for CYP3A4 (49). 17-Ethynylestradiol is a major component of oral contraceptive pill and is also used in hormonal replacement therapy in postmenopausal women. It is metabolized through hydroxylation in position 2 by CYP3A4 (50). St. John's wort has significant interaction with oral contraceptives (51). Muprhy et al. studied interaction between St. John's wort and oral contraceptives by investigating phramacokinetics of norethindrone and ethinyl estradiol using 16 healthy women. Treatment with St. John's wort (300mg three times a day for 28 days) resulted in a 13-15% reduction in dose exposure from oral contraceptives. Breakthrough bleeding increased in treatment cycle as did evidence of follicle growth and probable ovulation. Authors concluded that St. John's wort increased metabolism of norethindrone and ethinyl estradiol and thus interfered with contraceptive effectiveness (52).

Natural Cures For Menopause

Natural Cures For Menopause

Are Menopause Symptoms Playing Havoc With Your Health and Relationships? Are you tired of the mood swings, dryness, hair loss and wrinkles that come with the change of life? Do you want to do something about it but are wary of taking the estrogen or antidepressants usually prescribed for menopause symptoms?

Get My Free Ebook


Post a comment