Although it is a dietary supplement, milk thistle can theoretically interact with medications. However, little conclusive information is available about milk thistle interactions. Early research suggests that milk thistle may decrease the activity of certain liver enzymes. These enzymes are responsible for breaking down many different medications, hormones, toxins, and various other substances in the body. However, because so little information is available, it is not known which medications might interact with milk thistle or how exactly to handle these interactions.
The prescribing information for one prescription medication, Olysio™ (simeprevir), specifically mentions that it should not be taken with milk thistle, due to the risk of milk thistle increasing blood levels of Olysio.
If you take any prescription medications, check with your healthcare provider before taking milk thistle. This is especially important for medications with dangerous side effects (such as arrhythmia medications or blood thinners), life-saving medications (such as HIV medications), or those for which the effectiveness is very important (such as birth control pills). Your healthcare provider may want to monitor you more closely and adjust the dose of your other medications if necessary.
In all cases, don't forget to mention milk thistle when your healthcare provider asks about which medications and supplements you are taking.
Written by/reviewed by: Kristi Monson, PharmD;Arthur Schoenstadt, MD
Last reviewed by: KristiMonson, PharmD;
List of references (click here):
Jellin JM, editor. Pharmacist's Letter/Prescriber's Letter Natural Medicines Comprehensive Database Web site. Available at: http://naturaldatabase.com/. Accessed August 11, 2008.
Agency for Healthcare Research and Quality (AHRQ). U.S. Department of Health and Human Services Milk thistle: effects on liver disease and cirrhosis and clinical adverse effects. Summary, evidence report/technology assessment: Number 21 (September 2000). AHRQ Web site. Available at: http://www.ahrq.gov/clinic/epcsums/milktsum.htm. Accessed August 11, 2008.
National Center for Complimentary and Alternative Medicine. National Institutes of Health. Herbs at a glance: milk thistle (March 2008). NCCAM Web site. Available at: http://nccam.nih.gov/health/milkthistle/. Accessed August 11, 2008.
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