Evidence based review of natural health products for non-specific low back pain

Introduction - Natural health products (e.g., vitamins, minerals, herbal medicines) are frequently used for musculoskeletal pain and there is an increasing amount of high quality research being done to test the efficacy of these interventions. Low back pain is a very common condition and individuals suffering from these conditions are frequently seeking out these products. Objective - The objective of this paper is to review and summarize the evidence surrounding natural health products for chronic non-specific low back pain. Methods - We searched for systematic reviews and randomized controlled trials in PubMed and the Cochrane Library. We performed a best evidence synthesis of the resulting papers. Results - We included two systematic reviews and 2 additional randomized controlled trials published subsequently to these reviews. We found strong evidence for 50 mg harpagoside per dose of an aqueous extract of Harpagophytum procumbens per day reduces pain more than placebo. We found moderate evidence for 100 mg harpagoside per dose of an aqueous extract of Harpagophytum procumbens compared to placebo, for an extract of willow bark yielding 120 mg salicin per day compared with placebo, for 240 mg of salicin per day in reducing pain to a greater extent than placebo, for 240 mg of salicin per day as equivalent to 120 mg salicin, for no differences in pain and function between a 60 mg daily harpagoside dose of an aqueous extract of Harpagophytum procumbens and 12.5 mg rofecoxib per day, for no difference in pain and overall improvement between Spiroflor SRL homeopathic gel (SRL) and Cremor Capsici Compositus FNA, the capsici oleoresin gel, for intramuscular B12 when compared with placebo. We found limited evidence for topical Capsicum frutescens in the form of Rado-Salil cream or a Capsicum plaster for reducing pain more than placebo, for lavender oil in the treatment of chronic NSLBP, or vitamin C, zinc, and manganese in addition to prolotherapy. Adverse events for all interventions appeared to be mild and transient though we did not attempt to identify all relevant literature concerning adverse events. Conclusions - There is some evidence for several natural health products in the treatment of chronic non-specific low back pain. More research is needed for all of these interventions before they are incorporated into routine clinical practice and their reporting must be improved by referring to the recently published extensions of the CONSORT statement.