Herbal medicine for low back pain

Low-back pain is a common condition and a substantial economic burden in industrialized societies. A large proportion of patients with chronic low-back pain use complementary and alternative medicine (CAM), visit CAM practitioners, or both. Several herbal medicines have been purported for use in low-back pain.

To determine the effectiveness of herbal medicine for non-specific low-back pain.

We searched the following electronic databases: Cochrane Complementary Medicine Field Trials Register (Issue 3, 2005), MEDLINE (1966 to July 2005), EMBASE (1980 to July 2005); checked reference lists in review articles, guidelines and retrieved trials; and personally contacted individuals with expertise in this very specialized area.

We included randomized controlled trials, examining adults (over 18 years of age) suffering from acute, sub-acute or chronic non-specific low-back pain. The interventions were herbal medicines, defined as plants that are used for medicinal purposes in any form. Primary outcome measures were pain and function.

Two authors (JJG & MVT) conducted the database searches. One author contacted content experts and acquired relevant citations. Full references and abstracts of the identified studies were downloaded. A hard copy was retrieved for final inclusion decisions. Methodological quality and clinical relevance were assessed separately by two individuals. Disagreements were resolved by consensus.

Ten trials were included in this review. Two high quality trials examining the effects of Harpagophytum Procumbens (Devil's Claw) found strong evidence that daily doses standardized to 50 mg or 100 mg harpagoside were better than placebo for short-term improvements in pain and rescue medication. Another high quality trial demonstrated relative equivalence to 12.5 mg per day of rofecoxib (Vioxx). Two trials examining the effects of Salix Alba (White Willow Bark) found moderate evidence that daily doses standardized to 120 mg or 240 mg salicin were better than placebo for short-term improvements in pain and rescue medication. An additional trial demonstrated relative equivalence to 12.5 mg per day of rofecoxib. Three low quality trials on Capsicum Frutescens (Cayenne), examining various topical preparations, found moderate evidence that Capsicum Frutescens produced more favourable results than placebo and one trial found equivalence to a homeopathic ointment.

Harpagophytum Procumbens, Salix Alba and Capsicum Frutescens seem to reduce pain more than placebo. Additional trials testing these herbal medicines against standard treatments are needed. The quality of reporting in these trials was generally poor. Trialists should refer to the CONSORT statement extension for reporting trials of herbal medicine interventions.