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.
Hello Trevor and Tyler – what are the two main things you learned from preparing and developing this topic?
Hello Dr. Shane-McWhorter,
I learned that cat’s claw has been used medicinally for thousands of years. I also learned that cat’s claw may be effective at reducing pain associated with activity in individuals with OA.
Hello Dr. Shane-McWhorter – Great question! I would say the two main things I learned from preparing this poster was how little human studies are done on cat’s claw. Surprisingly there were only two studies we could find. I think it is interesting since these two studies have shown some benefit that there are not more studies trying to show benefit for osteoarthritis treatment. The second thing I thought was interesting was how cat’s claw has been shown to stimulate phagocytes and leukocytes to have an immunostimulating effect and therefore can have drug-drug interactions with immunosuppressants.
Interesting topic. In the first study what were pre and post study pain scores? How was mild to moderate osteoarthritis determined? What would you say to a person that wants to use cat’s claw for osteoarthritis.
In the placebo group, participants reported an average resting pain score of 4.2, an average activity pain score of 6.8, and an average night pain score of 4.6. In the intervention group, participants reported an average resting pain score of 4.4, an average activity pain score of 5.7, and an average night pain score of 4.6. After 4 weeks, scores for the placebo group were 3.94, 6.2, and 4.17 respectively. For the intervention group, the scores were 3.42, 3.5, and 3.06 respectively.
Mild to moderate knee osteoarthritis was determined by using the Kellgren and Lawrence classification system for OA. Participants in this study were classified as grade II or III in this classification system.
If an individual wanted to used cat’s claw for OA, I would encourage them to use first line treatments for OA such as NSAIDS, acetaminophen, intra-articular steroids, or duloxetine. This is because first line treatments for OA have more evidence and data supporting their use in all types of OA. I would also mention to the patient that evidence supporting cat’s claw’s use in OA is very limited and has only been studied in healthy individuals with mild to moderate knee OA. Lastly, I would mention that cat’s claw may only improve pain associated with activity.
Hello Trevor and Tyler!
Given its anti-inflammatory effects, have there been any benefits or studies of patients taking Cat’s Claw for rheumatoid arthritis?
Hey Ryley! Thanks for the great question. Only one study has examined the benefits and effectiveness of cat’s claw for rheumatoid arthritis. The clinical trial demonstrated that a particular extract in cat’s claw showed moderate improvement for the symptoms of RA. The cat’s claw medication provided was dosed at 20 mg three times daily orally. Cat’s claw comprises of an extract called pentacyclic oxindole alkaloids, which induces human endothelial cell growth. The cat’s claw extract had 14.7 mg/gram in this study. This study had a second phase that revealed that cat’s claw combined with sulfasalazine or hydroxychloroquine reduced the number of painful joints in a 24-week trial compared to placebo.
Hi guys, great poster and an interesting topic. What made you pick this herbal supplement?
Thanks for your feedback! So I work at Smith’s Pharmacy, and a couple weeks ago a gentleman that came in asked our pharmacist if he could use cat’s claw for his OA. My pharmacist told him that there wasn’t a lot of evidence supporting it’s use, so he recommended that the individual use topical diclofenac instead. I thought this was an interesting supplement, one that I had never heard of before, so Tyler and I thought it would be an interesting topic for our poster.
Hey Jackie! Thanks for the compliments! We chose this herbal supplement because Trevor Judd is a big cat guy, so when he saw this herbal medication he quickly convinced me that we should choose this one.
Trevor and Tyler, do you think that freeze dried cat’s claw might result in a difference in results?
Good question! According to the authors of this study, the freeze dried cat’s claw used is a lot more potent compared to other formulations. Because of this, it can be assumed that a non-freeze dried formulation may need a higher dose in order to witness similar results. With that being said, however, a different study using non-freeze dried cat’s claw would need to be conducted in order to address your question.
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