PO (Adults): Hepatic cirrhosis — 420 mg/day of extract containing 70–80% silymarin; Chronic active hepatitis — 240 mg bid of silibinin; Tea — 3–4 times daily 30 minutes before meals. Tea is not recommended as silymarin is not sufficiently water soluble.
IV (Adults): 20–50 mg/kg over 24 hr, 48 hr post mushroom ingestion (IV formulation not available in US).
Natural-Drug Products:In vitro, milk thistle extract inhibited the drug-metabolizing enzyme cytochrome P450 3A4. Interactions have not been reported in humans, but milk thistle should be used cautiously with other drugs metabolized by 3A4, such as cyclosporin e, carbamazepine, HMG-CoA inhibitors, ketoconazole, and alprazolam.