Devil’s claw – a promising remedy for pain
The Irish Times
Health Supplement, p. 13
2 December 2008
DOES IT WORK? Devil’s claw and osteoarthritis
DEVIL’S CLAW is a ground-trailing plant which gets its name from its strange-looking fruit. After the flowers die, they leave a woody fruit which has long, barbed spines.
The plant is native to many parts of southern Africa, where it is also called the grapple plant or wood spider. The part used medicinally, however, is underground. The roots grow tubers which look like sweet potatoes and have been used traditionally to relieve inflammation, pain and stomach problems.
The herbal remedy was studied extensively in Germany at the beginning of the 20th century. Recent interest has focused on its potential to relieve pain and inflammation associated with osteoarthritis.
Evidence from studies
Early work with devil’s claw identified numerous substances with some medicinal potential. However, many of these studies were conducted with older tests and used extracts prepared in many different ways. This research demonstrated that compounds called “iridoid glycosides” are the active ingredients with most potential. Laboratory studies have shown that these compounds have beneficial effects on the biochemical pathways involved in osteoarthritis.
A number of German products are now available which are standardised to contain fixed amounts of these glycosides, in particular a compound called harpagoside. Recent clinical research has been conducted with these standardised products, though many other products are also available on the market.
About a dozen clinical trials have been conducted with devil’s claw, but many of them were of poor quality. In one study, 250 patients with osteoarthritis took devil’s claw capsules containing 60mg/day of harpagoside. This is the most commonly recommended dose. After eight weeks, over half the patients reported some improvements. However, no control group was included here. In another study, the effect of devil’s claw was compared to that of a convention medication (called diacerhein). After four months, patients in both groups reported similar relief from osteoarthritis, while those taking devil’s claw had fewer adverse effects.
Two other small studies have compared devil’s claw to a conventional drug that was used to treat pain in patients with arthritis and other muscle and joint problems. Vioxx has since been withdrawn from the market, but in the clinical studies devil’s claw was found to give similar pain relief as Vioxx after six weeks and one year. The trials were too small to provide definite results, but they indicate that larger studies would be worthwhile.
Problematic aspects
In general, devil’s claw does not have serious adverse effects. However, in one clinical trial almost one in 10 participants had diarrhoea. Some others had problems such as nausea and vomiting. Traditionally, devil’s claw was said to help stimulate the appetite by increasing the production of stomach acid.
While this has not been studied in clinical trials, anyone with stomach irritation or gastric ulcer would probably be best to avoid devil’s claw. Pregnant women should not take devil’s claw as it contains plant steroids which allegedly can stimulate the uterus.
Recommendations
Osteoarthritis is a chronic and debilitating condition that affects many people. The best approach to managing the condition involves a suitable combination of exercise, weight-loss, physiotherapy and various medications.
While many dietary supplements and herbal remedies are now being marketed for osteoarthritis, few have been tested rigorously or extensively.
Devil’s claw is a herbal remedy that shows promise in this area. While very few clinical trials have been conducted, it has been shown to be as effective as some other conventional medications used for osteoarthritis.
However, since the symptoms of osteoarthritis vary a lot, it will be important to test devil’s claw in larger and longer-lasting studies.
If you are considering a trial period with devil’s claw, discuss with your healthcare professionals. Your symptoms should be carefully monitored to ensure maximum benefit from all your interventions.
Bioethics Ireland 