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St Johns Wort × Oral Contraceptives

MODERATE INTERACTION — Well-Established Evidence

⚠️ Mechanism

St. John's wort induces CYP3A4, increasing metabolism of estrogen in oral contraceptives.

📋 Effect

Reduced contraceptive efficacy; breakthrough bleeding; unintended pregnancy risk

💊 Management

Avoid combination. Use alternative contraception or avoid St. John's wort.

Plain Language Summary

This combination can be risky because St. John's Wort causes the body to break down the hormones in oral contraceptives more quickly. This process can make the birth control less effective and increase the risk of an unintended pregnancy.

Source

Hall SD et al. Clin Pharmacol Ther 2003; Murphy PA et al. J Clin Pharmacol 2005

Supporting Research

The effect of Hypericum perforatum on postmenopausal symptoms and depression: A randomized controlled trial PMID:31331546 DOI:10.1016/j.ctim.2019.05.028 2019
Hypericum extract LI 160 and fluoxetine in mild to moderate depression: a randomized, placebo-controlled multi-center study in outpatients PMID:15538592 2005
[Hypericum perforatum extract in treatment of mild to moderate depression. Clinical and pharmacological aspects] PMID:12212522 2002
Hypericum perforatum versus fluoxetine in the treatment of mild to moderate depression PMID:12008860 2002
Efficacy of continuation treatment with hypericum perforatum in depression PMID:12019675 2002
Predicting stable treatment response in patients with major depression treated with hypericum extract WS 5570/5572 PMID:16189745 2005
Adverse Event Profile: St Johns Wort 0
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Medical Disclaimer: This interaction record is for informational and educational purposes only and does not constitute medical advice. Drug-supplement interactions can be dangerous. Always consult your healthcare provider or pharmacist before combining any supplement with prescription medications. Do not stop or change any medication without professional guidance.