⚠️ Mechanism
Milk Thistle is a weak inhibitor of CYP3A4, which decreases metabolism of CYP3A4 substrates, potentially increasing their plasma concentrations and risk of adverse effects.
📋 Effect
Increased plasma levels of ethinylestradiol (oral-contraceptives), potentially leading to toxicity or enhanced adverse effects.
💊 Management
Monitor for increased adverse effects of ethinylestradiol. Dose reduction may be necessary. Consider alternative supplement or consult healthcare provider.
Plain Language Summary
This combination may be unsafe because it can cause higher levels of oral contraceptives to build up in your body. Milk thistle can slow down the process your body uses to break down the medication, which may increase your risk of side effects.
Source
Flockhart CYP450 Table (drug-interactions.medicine.iu.edu)