Report on Cat’s Claw Side Effects and Usage

Cat’s Claw

Natural health supplements sometimes have unexpected side effects or interactions with medication that can lead to adverse reactions that are sometimes life threatening. The following is a list of cautions that you should be aware of before using Cat’s Claw (Uncaria tomentosa, U. guianesis). These are referred to as drug/herb interactions.

Warning 1 – Antihypertensives: Cat’s Claw may increase the effects of antihypertensives. If your blood pressure is already too low, this may be a problem. Drugs used to treat high blood pressure include captopril (Capoten), enalapril (Vasotec), losartan (Cozaar), valsartan (Diovan), diltiazem (Cardizem), Amlodipine (Norvasc), hydrochlorothiazide (HydroDiuril), furosemide (Lasix), and many others.

Warning 2 – Hormones: may interact with hormones made from animal products.

Warning 3 – Insulin: Cat’s Claw may interact with insulin.

Warning 4 – Plasma, fresh: Cat’s Claw may interact with fresh plasma.

Warning 5 – Vaccines (passive): Cat’s Claw may interact with passive vaccines composed of animal sera.

Warning 6 – Liver: Medications that are broken down by the liver (Cytochrome P450 3A4 (CYP3A4) substrates) interact with Cat’s Claw. These include triazolam (Halcion), lovastatin (Mevacor), ketoconazole (Nizoral), itraconazole (Sporanox), fexofenadine (Allegra), and many others.

Warning 7 – Surgery: There is some evidence that Cat’s Claw may make control of blood pressure difficult during surgery. Experts recommend discontinuing Cat’s Claw at least 2 weeks before a scheduled surgery.

Warning 8 – Leukemia: Cat’s claw may worsen this condition. Experts recommend avoiding this herb if you have leukemia.

Warning 9 – Immunostimulants: Cat’s claw may stimulate the immune system. By increasing the immune system cat’s claw might decrease the effectiveness of medications intended to decrease the immune system. These drugs include corticosteroids (glucocorticoids), basiliximab (Simulect), cyclosporine (Neoral, Sandimmune), daclizumab (Zenapax), tacrolimus (FK506, muromonab-CD3 (OKT3, Orthoclone OKT3), azathioprine (Imuran), mycophenolate (CellCept), Prograf), sirolimus (Rapamune), prednisone (Deltasone, Orasone), and others.

Because of the risk of stimulating the immune system, the symptoms of auto-immune diseases such as multiple sclerosis (MS), lupus (systemic lupus erythematosus, SLE), and similar conditions may be made worse by the use of Cat’s claw.

Warning 10 – Pregnancy: The safety of using cat’s claw during pregnancy and breast-feeding is unknown.

Used as a natural health remedy: Cat’s Claw has been used for the following conditions:

  • AIDS
  • Arthritis pain (See other herbs for inflammation)
  • Cancer
  • Chronic fatigue
  • Chronic inflammation
  • Cold
  • Flu
  • Gastric ulcers
  • Herpes
  • Lupus
  • Rheumatism

Side Effects of Cat’s Claw

The known side effects of using Cat’s Claw include the following:

  1. dizziness
  2. headache
  3. vomiting

Other side effects may also occur when using Cat’s Claw. (See form below)

As with any herb, a serious allergic reaction is possible. Seek immediate medical attention if you notice any symptoms of a serious allergic reaction. These may include a rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing.

Return to the Herb List.

For questions and answers about the side effects of herbs see the Herb Forum

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