Cat's Claw

Cat's claw is thought to have anti-inflammatory effects and has been used for rheumatoid arthritis and osteoarthritis. Compounds in cat's claw are thought to block the body's production of inflammation-producing substances called prostaglandins and tumor necrosis factor (TNF). Cat's claw is believed to reduce pain somewhat, but it doesn't appear to have much of an effect on reducing swelling. More evidence is needed before cat's claw can be used as a treatment for arthritis.

There's some evidence cat's claw may affect the immune system. Preliminary laboratory studies suggest it may halt the spread of cancer cells. A few animal studies suggest it may help with cell damage caused by chemotherapy or radiation treatment. Much more evidence is needed before it can be used as a cancer treatment, and it should never replace conventional care.

Cat's claw has also been used for high blood pressure, HIV, diverticulitis, gastritis, Crohn's disease and ulcerative colitis, but there's insufficient evidence on the effectiveness of cat's claw for these conditions.

Side Effects and Safety Concerns

Side effects may include nausea, headache and dizziness.

Cat's claw shouldn't be used by people who have had organ transplants.

The safety of cat's claw in people with certain autoimmune conditions such as type 1 diabetes, multiple sclerosis, systemic lupus erythematosus and Crohn's disease isn't known.

Cat's claw shouldn't be taken within two weeks before or after surgical procedures or by people who have bleeding disorders.

Pregnant or nursing women or children should avoid cat's claw.

Cat's claw shouldn't be confused with another herb called cat's claw acacia, catclaw acacia or Acacia gregii which is believed to contain a compound related to cyanide and should not be taken orally.

Possible Interactions

Cat's claw may decrease the effectiveness of drugs that suppress the immune system such as Imuran (azathioprine), CellCept, Neoral, Sandimmune (cyclosporine), Prograf, Rapamune and Zenapak.

Cat's claw is thought to be broken down by the liver, so it could theoretically interfere with the effectiveness of medications that are broken down by the same liver enzymes such as:

• oral contraceptives
  
• allergy medication such as fexofenadine
  
• cholesterol medication such as lovastatin
  
• antifungals such as ketoconazole
  
• cancer medications such as paclitaxel or vinblastine