Why was this study done?
Low-back pain is the second most common cause of work absence in industrialized countries. Patients with chronic low-back pain are more likely to use alternative medicines or visit an alternative practitioner than patients with other types of pain. Alternative treatments for back pain include oral and topical herbal medicines, some of which have been studied in clinical trials. This systematic review was conducted to determine the effectiveness of herbal medicine compared with fake treatment (placebo) or other treatments.
How was the study done?
Researchers searched four databases for randomized, controlled trials. They found that three oral herbal medications had been tested in 10 clinical trials. A total of 1,567 adults with non-specific acute or chronic low-back pain participated in these trials. In these studies, two oral herbal medications, Devil's Claw (Harpagophytum Procumbens) and White Willow Bark (Salix Alba), were compared with a placebo (fake pills) and with the drug rofecoxib (Vioxx). A topical cream, Cayenne (Capsicum frutescens) was compared with placebo and a homeopathic gel.
What did the reviewers find?
Devil's Claw, in a standardized daily dose of 50 mg or 100 mg, reduced pain more than the placebo, in two high quality trials. A daily dose of 60 mg reduced pain about the same as a daily dose of 12.5 mg of Vioxx in another high quality trial. Willow Bark, in a standardized daily dose of 120 mg and 240 mg, reduced pain more than the placebo in two moderate quality trials. A daily dose of 240 mg reduced pain about the same as a daily dose of 12.5 mg of Vioxx. Cayenne reduced pain to a greater extent than the placebo and about the same as the homeopathic gel, Spiroflor SLR. The side effects reported were mainly mild, temporary stomach complaints.
What are some strengths and weaknesses of the study?
Most of the trials were of moderate or high quality, but they only tested the effects of short-term use (up to six weeks). In more than half of the studies, the authors were either judged to have a potential conflict of interest or did not report conflict of interest.