Devil’s claw

CLINICAL SUMMARY

Derived from the root or tuber. Clinical studies reveal conflicting data about efficacy of devil's claw as an anti-inflammatory or analgesic. It has been thought that the iridoid glucosides may be responsible for activity, but they are not active when administered separately from whole root extract. The basis for chemical standardization is unknown. Analysis of commercial products reveals wide variance in chemical components. Limited side effects have been reported; diarrhea and bradycardia also occur. An open clinical study suggests that Devil's claw may benefit patients with osteoarthritis of the hip or knee. Devil's claw Devil’s claw increases gastric acid secretions and may interfere with the activity of antacids and histamine-2 blockers (e.g. ranitidine and famotidine). Other possible drug interactions include increased activity of anticoagulants and cardiac and anti-arrhythmic drugs.

 PURPORTED USES

• Anorexia
• GI disorders
• Inflammation
• Muscle pain
• Osteoarthritis
• Pain

MECHANISM OF ACTION

In animal studies, an aqueous extract containing chiefly harpagoside showed significant dose-dependent anti-inflammatory and analgesic effects. Harpagoside is not implicated in the anti-inflammatory action, but, along with other constituents, it does appear to be involved in the peripheral analgesic properties. Devils claw also has antioxidant effects by scavenging both superoxide and peroxyl in a dose dependent manner. The bitter iridoids are responsible for the use of the herb as a stomachic. In vitro and in vivo animal studies have shown some evidence that devil's claw might be cardioactive. Lower doses seem to cause bradycardia and increase the strength of contraction, and high doses seem to weaken heart contractions and coronary blood flow.