Answer
St John's wort induces CYP3A4 and may reduce plasma concentrations of conjugated oestrogens, possibly decreasing therapeutic effects and/or changing the uterine bleeding profile.
Sources for this answer
- Conjugated Oestrogens 0.625mg coated tabletsPfizer Limited · emc · SmPC §4.5 Interaction with other medicinal products · Version 1Document updated
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