There is currently no reliable evidence available for the effectiveness of cat’s claw for any of its uses. More rigorous studies are needed.
Cat’s claw appear to be well-tolerated when taken by mouth for short term use. There are some reports of dizziness, nausea, vomiting, and diarrhea.
Cat’s claw can slow blood clotting. When it is taken with other medications that can affect your body’s ability to clot blood, cat’s claw can increase the chance of bleeding.
There may be an interaction between cat’s claw and the following medications:
- blood-pressure-lowering medications (e.g., furosemide, hydrochlorothiazide, metoprolol, ramipril, valsartan, amlodipine)
- blood thinning medications (e.g., warfarin, clopidogrel, ASA)
- immunosuppressants (e.g., cyclosporine, azathioprine, prednisone)
- HIV medications (e.g., amprenavir, nelfinavir, ritonavir, saquinavir)
- medications that are affected by certain liver enzymes (e.g., ketoconazole, itraconazole, triazolam)
People who are pregnant or trying to become pregnant should avoid using cat’s claw because of its past use as a contraceptive. Those who are breast-feeding should also avoid using cat’s claw.
Before taking any new medications, including natural health products, speak to your physician, pharmacist, or other health care provider. Tell your health care provider about any natural health products you may be taking.