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St Johns Wort × Theophylline

MODERATE INTERACTION — Probable Evidence

⚠️ Mechanism

St. John's wort induces CYP1A2, increasing theophylline metabolism.

📋 Effect

Reduced theophylline levels; loss of bronchodilation

💊 Management

Monitor theophylline levels. May need dose increase.

Plain Language Summary

This combination carries a moderate risk because St. John's Wort can cause your body to break down theophylline more quickly. This may lead to lower levels of the medication in your system, which could make it less effective at helping you breathe.

Source

Nebel A et al. Clin Pharmacol Ther 1999

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.