Devil's claw

Devil’s claw is a herbal medicine. You can buy capsules, tinctures (a medicine made by dissolving the active ingredient in alcohol) and fluid extract over the counter. We don’t yet understand how it works, but evidence suggests that devil’s claw is as effective as conventional medicines for osteoarthritis. Side-effects are still a concern.

• Family: Herbal medicine of the Bignoniaceae family
• Scientific name: Harpagophytum procumbens
• Other names: Grapple plant, wood spider, Doloteffin®, Rivoltan®, iridoid glycoside, WS 1531

Devil’s claw is a plant native to deserts of South and South East Africa. Extracts from the plant root are used medicinally to treat several diseases. You can buy devil’s claw from high-street retailers.

As yet, we don’t completely understand how devil’s claw works. Laboratory studies found that extracts from the plant root can block several pathways which cause joint inflammation. These anti-inflammatory properties are thought to be due to its active ingredient, harpagoside, but animal studies found that its painkilling properties can’t be explained by this ingredient alone.

Although uncommon, devil’s claw can cause serious side-effects of abnormal heart rhythm and bleeding. Other, less serious side-effects include:

• rashes
• stomach upsets
• diarrhoea
• headaches
• loss of appetite.

Devil’s claw has been reported to interact with anticoagulants, painkillers, heart drugs (for example digoxin) and stomach acid drugs (for example famotidine). You should use a dose of 500–1,500 mg of dried root or capsules three times daily.

Systematic review 1

This review reported five RCTs dating from 1980 into the use of devil’s claw for osteoarthritis of the hip or the knee.

Three studies (two of which were considered to be of high quality) compared devil’s claw with a placebo. Participants who were given devil’s claw had a significant improvement in osteoarthritis-related pain compared to those who were on a placebo.

One high-quality study compared the level of pain improvement in participants randomly selected to receive devil’s claw with that of participants assigned to take phenylbutazone (an non-steroidal anti-inflammatory drug). Participants taking devil’s claw reported fewer side-effects and had slightly better pain improvement.

Another high-quality study compared the overall disease-related symptoms in two groups of participants who were randomly assigned to take either devil’s claw or diacerhein*, a conventional therapy for osteoarthritis. Improvements were similar in both groups following treatment, but participants given devil’s claw experienced fewer side-effects.

Systematic review 2

The above trials were reviewed in a more recent scientific article. It found that results of the high-quality trials suggest that devil’s claw is effective in the reduction of osteoarthritis-related symptoms.

*NB: Diacerhein can be spelt with or without the ‘h’.