"Milk Thistle (Silymarin)" TUMOR TIDBITS, A BIWEEKLY EMAIL NEWSLETTER FROM GULF COAST VETERINARY ONCOLOGY Number 91; March 7, 2003. ======================================================================= THIS WEEK'S TUMOR TIDBIT: Milk Thistle (Silymarin) ======================================================================= WHAT IS SILYMARIN? Silymarin refers to the extract from the seeds of the plant Silybummarianum, also called "milk thistle". It has been used for over 2,000 years. During the Middle Ages the seed of the milk thistle was commonly used to treat liver diseases. The active ingredients of milk thistle are chemicals called flavonoids. The flavonoids in milk thistle are silybin, silydianin, and silychristin. Together, they are called silymarin. WHAT ARE THE BENEFITS OF SILYMARIN? Silymarin protects the liver by acting as an antioxidant scavenging free radicals and inhibiting lipid peroxidation, and by promoting the growth of new liver cells. Silymarin also helps with the digestion of fats. It appears to help keep harmful substances out of liver cells. Milk thistle can help prevent or reverse liver damage caused by alcohol, recreational drugs, pesticides, some poisons, or hepatitis. Silymarin has been used (especially in Europe) to treat hepatitis, liver damage due to alcoholism, and poisoning by certain types of mushrooms. HOW IS SILYMARIN USED? Silymarin is an extract of the seeds of the milk thistle plant. A standardized extract should be 80% silymarin (the active ingredient). The usual dosage of milk thistle extract is between 300 milligrams(mg) and 600 mg daily in humans. It is widely available at health food stores and some recommendations for use in the dog are: Dry herb powder - 15-20 mg/lb PO SID 80% extract of Silymarin - 5-6 mg/lb PO SID WHAT ARE THE SIDE EFFECTS? There are no documented side effects of milk thistle. Even very high doses do not seem to have any negative effects. However, some pet owners have reported nausea in their dogs (upset stomach or diarrhea) after long term use. HOW DOES IT INTERACT WITH OTHER THERAPIES? There are no documented interactions of milk thistle with other therapies. In fact, Silymarin has shown synergistic effects with cisplatin and doxorubicin in vitro, reduction of nephrotoxicity from cisplatin in people, and a lack of interference with chemotherapy in people with acute promyelocytic leukemia. HOW DO WE KNOW IT WORKS? We don’t. However, milk thistle has been used for over 2,000 years, so a lot has been written about its health effects. There have been over 300 scientific studies of silymarin that document in people: Antioxidant effects Treatment of cirrhosis of the liver caused by alcoholism Treatment of chronic hepatitis Treatment of poisoning due to eating wild mushrooms Helping the liver repair itself WHAT DO WE DO AT GULF COAST? In most of our pets diagnosed with hepatic cancer (primary or secondary) or on long- term alkylating drug chemotherapy, we recommend and prescribe Silymarin. ======================================================================= As always, we hope this info helps and don't hesitate to call or email us Gulf Coast Veterinary Oncology! Kevin A. Hahn, DVM, PhD, Diplomate ACVIM (Oncology), drhahn@gcvs.com Janet K. Carreras, VMD, Diplomate ACVIM (Oncology), drcarreras@gcvs.com Glen K. King, DVM, MS, Diplomate ACVR (Radiology & Radiation Therapy), drking@gcvs.com Gulf Coast Veterinary Diagnostic Imaging & Oncology 1111 West Loop South, Suite 150, Houston, TX 77027 P: 713.693.1166 F: 713.693.1167 W: www.gcvs.com