Abstract: Does Cat’s Claw Help With Osteoarthritis?
Tyler Lister and Trevor Judd
Background: Cat’s claw is a woody vine that can be found in Central and South America.1,4 Cat’s claw has two main species.1 These species are uncaria tomentosa and uncaria guianensis.1 It has been used for various health reasons by the indigenous people of these lands for thousands of years.4 One of the main indications it is used for today is osteoarthritis.1
Pharmacology: Cat’s claw has anti-inflammatory, chondroprotective, and antioxidant effects.1,6 It inhibits TNF-alpha and PGE2 production.1 It also inhibits NFKB activation.1,6 It’s chondroprotective effects comes from upregulation of type II collagen and aggrecan.1 It also inhibits matrix metalloproteinases and nitric oxide.1 Cat’s claw has several drug interactions that health care providers should be aware about.1,4,6 First of all, cat’s claw increases bleeding risk and decreases blood pressure.1,4,6 Consequently, anticoagulants and antihypertensives should be used with caution with this supplement.1,4,6 It is also immunostimulating and can react with immunosuppressive medications.1,4 Lastly, it inhibits CYP3A4, which may cause other drugs metabolized by this enzyme to build up in an individual’s body.1,6 Common side effects of this medication include GI issues, neuropathy, anemia, fatigue, and itchy skin lesions.1,4,5,6
Clinical Evidence: One prospective, multicenter, randomized, placebo-controlled trial compared the safety and efficacy of freeze dried cat’s claw to placebo.3 The study duration was 4 weeks and each intervention was dosed daily (cat’s claw’s dose was 100 mg).3 Participants in this study were mainly males, aged 45-75 years old, with mild to moderate knee osteoarthritis.3 Participants of this study were fairly healthy individuals, with no serious comorbidities. Outcomes of this study were patient and physician knee pain scores at night, rest, and activity.3 Of these, only pain associated with activity was decreased by cat’s claw and this reduction was significant (p<0.001).3 Cat’s claw was not associated with any serious side effects in this study.3
Our second study was a multicenter, randomized double-blind, positive control study in Mumbai, India that was assessing safety and efficacy of glucosamine against Reparagen.2 Reparagen is a combo herbal medication that has cat’s claw and maca. The study duration was for 8 weeks for adults of either sex over the age of 20 diagonesed with mild to moderate knee osteoarthritis.2 There were 48 individuals assigned reparagen 1,800mg (300mg cat’s claw & 1,500mg maca) daily and 47 individuals assigned glucosamine sulfate 1,500mg daily.2 To assess participants’ response to each medication they used WOMAC and VAS pain scales. To be considered a “responder” the participant should have at least a 20% reduction in WOMAC pain. Outcomes showed that 89% of the glucosamine group were responders while 93% of the reparagen were responders.2 The results of the study showed both medications were well tolerated without any severe side effects while reparagen showed a small benefit over glucosamine.2
Conclusions: While looking into these two case studies, cat’s claw alone did reveal some osteoarthritis pain alleviation during activity but not during rest or at night.3 Cat’s claw in combination with maca displayed a slightly better response in pain than glucosamine sulfate.2 That study does not distinguish which component in Reparagen was more effective for the subject and their osteoarthritis, however. There is limited data showing cat’s claw provides relief for mild to moderate knee osteoarthritis as an alternative regimen. However, since this medication is well tolerated and not associated with critical adverse events, it could be trialed as a replacement therapy if first-line agents for osteoarthritis, such as NSAIDs, acetaminophen, injectable steroids, and capsaicin have not been working. Since this herbal medication does have a few drug interactions, all individuals taking other medications should be educated before taking cat’s claw.1,4,5,6 There are few studies regarding cat’s claw. Still, since this herbal has revealed a slight advantage, there is a cause for added studies to demonstrate the efficacy of pure cat’s claw for knee osteoarthritis and other types of osteoarthritis.
- Mehta K, Miller, M.J. Comparison of glucosamine sulfate and a polyherbal supplement for the relief of osteoarthritis of the knee: a randomized control trial.
- Picoya J, et al. Efficacy and safety of freeze-dried cat’s claw in osteoarthritis of the knee: mechanism of action of species Uncaria guianensis.