There are moderate interactions between silymarin and drugs that are metabolized (metabolized) in the liver via cytochromes P450 2C9. Concomitant use of silymarin and these drugs may slow their breakdown and increase their effects and side effects. Furthermore, there are interactions between milk thistle and glucuronidated drugs. In this case, the effect of the drugs may also be reduced. Silymarin has a minor effect on estrogens by reducing the effectiveness of these hormones. The effect of cholesterol-lowering drugs may also be slightly impaired by the simultaneous intake of silymarin. These interactions may occur at doses of 140 mg of silymarin or 5 g to 10 g of milk thistle. Therefore, because of the high dosage, these interactions are less clinically relevant.
