Reviewed: Gagnier JJ, VanTulder M, Berman B, Bombardier C. Herbal medicine for low back pain. Cochrane Database Syst Rev. April 19,2006;(2):CD004504.
Back pain is a common condition. In the United States, it is the most common cause of disability in people younger than 45 years.1 Low back pain is the second most frequent cause of work absence in industrialized nations2 and is a frequent reason for visits to a physician.3,4 These authors conducted a review of the scientific literature to determine the effectiveness of herbal medicines compared with placebo, no intervention, or other interventions in the treatment of nonspecific low back pain (defined as “pain between the lowest rib and the bottom of the buttocks that is not caused by serious, underlying problems such as rheumatoid arthritis, infection, fracture, cancer, or sciatica due to a herniated disc or other pressure on nerves”).
Included in this review were randomized controlled trials (RCTs) including adults (older than 18 years) suffering from acute (lasting up to 6 weeks), subacute (lasting 6 to 12 weeks), or chronic (lasting longer than 12 weeks) nonspecific low back pain. Herbal medicine was defined as “all or part of a plant that was used for medicinal purposes, administered orally or applied topically.” Outcome measures were pain intensity, functional status, overall improvement, and work status.
The authors searched the following databases: Cochrane Complementary Medicine Field Trials Registry (Issue 3, 2005); MEDLINE (1966 to July 2005); EMBASE (1980 to July 2005); and Clinical Evidence (January 2005). In addition, they reviewed reference lists in review articles, guidelines, and retrieved articles, and contacted persons with expertise in herbal medicine and low back pain to identify additional trials. Methodological quality and clinical relevance were assessed separately by 2 of the authors; disagreements were resolved by consensus.
For this review, 10 citations met the inclusion criteria. Three studies used an oral form of the herbal species devil’s claw (Harpagophytum procumbens, [Burch.] DC. ex Meisn., Pedaliaceae); 3 used an oral white willow bark (Salix alba L., Salicaceae); and 4 used topical cayenne (Capsicum frutescens L., Solanaceae). Four studies compared various oral herbal medicines with placebo; 2 studies compared oral herbal medicines with standard pain medications; 3 studies compared topical herbal medicines with placebo, and 1 compared a topical herbal medicine with a topical homeopathic medicine.
The authors note that most of the trials reviewed are of moderate or high quality, but they tested only the effects of short-term (up to 6 weeks) use. Also, the authors of half of the studies were judged to have a potential conflict of interest, and 2 others did not discuss conflict of interest.
After conducting the review, the authors of this review conclude that an aqueous devil’s claw extract at a standardized daily dosage of 50 mg harpagoside, a white willow bark extract at a standardized dosage of 240 mg salicin per day, and cayenne plaster seem to reduce low back pain more than placebo. “These herbal medicines could be considered as treatment options for acute episodes of chronic low back pain,” they write.
Following are the studies reviewed by these authors.
Oral Herbal Medicines Versus Placebo
One 4-week trial tested an extract of devil’s claw (Doloteffin®, Ardeypharm GmbH, Herdecke, Germany) standardized to 50 mg harpagoside (H) per day versus placebo in 118 patients with chronic low back pain.5 Results showed a significant increase in the number of pain-free patients in the 50 mg H group (9% to 17%) over the placebo group (2% to 5%). In another 4-week trial, 197 patients were given either a daily dose of devil’s claw extract (WS 1531®, W. Schwabe Pharmaceuticals, Karlsuhe, Germany; standardized to 100 mg H or 50 mg H), or placebo.6 The number of patients who were pain free for at least 5 days in the fourth week of treatment was significantly higher in the 100 mg group than in either the placebo group or the lower dose (50 mg H) group.
Two studies compared dried white willow bark with placebo. In the first study, 210 patients were divided into 3 groups and given either 2 doses of white willow bark standardized to either 120 mg or 240 mg salicin per day or placebo.7 The number of patients who were pain free for at least 5 days in the fourth week of treatment increased from baseline in the placebo group (n=4), 120 mg salicin group (n=15), and the 240 mg salicin group (n=27). The authors note that the trend for dose was significant, with the group receiving 240 mg salicin showing more improvement in the pain index than the group receiving 120 mg salicin. A second trial was designed to test platelet aggregation of white willow bark extract (Assalix®, Bionorica, Neumarkt, Germany) but did not measure clinically relevant outcomes.8
Oral Herbal Medicines Versus Standard Pain Medication
A study of 88 patients with acute episodes of chronic, nonspecific low back pain were given devil’s claw (Doloteffin®) standardized to 60 mg H per day or 12.5 mg rofecoxib (Vioxx®, a nonsteroidal anti-inflammatory drug) per day. Between the 2 groups, no statistically significant differences were seen in the number of patients who were pain free for at least 5 days in the sixth week of treatment.9
In a second study, 228 patients were given either a daily dose of willow bark extract (Assalix®), yielding 240 mg salicin, or a daily dose of 12.5 mg of rofecoxib. The study revealed no differences in effectiveness in the short term for patients with acute episodes of chronic, nonspecific low back pain.10
Topical Herbal Medicines Versus Placebo
In one trial, 40 patients with acute mechanical low back pain were treated for 14 days with either a cream called Rado-Salil® (containing ethysalicylate, methylsalicylate, glycosalicylate, salicylic acid, camphor, menthol, and oleoresin capsicum; Will-Pharma; The Netherlands) or a placebo cream containing oils of bergamot (Citrus bergamia Risso & Poit., Rutaceae) and oil of lavender (Lavandula spp. L., Lamiaceae).11 An improvement in pain score was seen in the Rado-Salil group, as well as a more favorable rating by both patients and physicians. (It is certainly questionable whether the bergamot and lavender essential oils are inert and thus whether they should have qualified as candidates for use as a placebo.)
In another trial, 154 patients with acute episodes of chronic, nonspecific low back pain were randomly assigned to a placebo plaster group or a group using a capsicum plaster (containing 12 mg of capsaicinoids per plaster) for 3 weeks.12 A 30% reduction in pain was reported in 60.9% of patients in the capsicum group and 42.1% of those in the placebo group. After treatment, 13.5% of the capsicum group and 6.6% of the placebo group were completely symptom-free.
In another study of patients with chronic low back pain, 320 patients were randomly assigned to a placebo plaster group or a capsicum plaster group for 21 days.13 (The topical capsicum plaster contained an ethonolic extract of cayenne pepper standardized to 22 mcg/cm2 of capsaicinoids.) Reduced pain, as well as improved function, was seen in the capsicum plaster group.
Topical Herbal Medicine Versus Homeopathic Treatment
In one trial, 161 patients (mixed group with new acute low back pain and acute episodes of chronic low back pain) were randomly treated for 7 days with either a Spiroflor SRL homeopathic gel (VSM; The Netherlands) or a Cremor Capsici Compositus FNA gel (Ratiopharm; The Netherlands).14 Each of the gels was applied at 3 g per day. Both groups showed a significant reduction in pain. The authors reported no statistically significant or clinically relevant differences in effectiveness between the 2 gels. Both groups showed a significant reduction in pain on the VAS (Visual Analog Scale), with a decrease of 38.2 mm in the SLR group and 36.6 mm in the CCC group. In the SLR group, 50% of subjects reported that treatment was 80% effective and 18% reported total (100%) effectiveness. In the CCC group, this was 55% and 15%, respectively.
The authors of this review conclude that “An aqueous extract of Harpagophytum procumbens at a standardized daily dosage of 50 mg harpagoside, an extract of Salix alba at a standardized dosage of 240 mg salicin/day, and a plaster of Capsicum frutescens seem to reduce pain more than placebo. These herbal medicines could be considered as treatment options for acute episodes of chronic low-back pain.”
—Shari Henson and Courtney Cavaliere
1. Borkan J, Reis S. Talking about pain: a patient-centered study of low back pain in primary care. Soc Sci Med. 1995;40(7):977-988.
2. Praemer A, Furner S, Rice DP. Musculoskeletal Conditions in the United States. Park Ridge, Ill: American Academy of Orthopaedic Surgeons; 1992.
3. Coste J, Delecoeuillerie G, Cohen de Lara A, Le Parc JM, Paolaggi JB. Clinical course and prognostic factors in acute low back pain: an inception cohort study in primary care practice. BMJ. February 26, 1994;308:577-580.
4. Andersson GBJ. Epidemiological features of chronic low-back pain. Lancet. August 14, 1999;354:581-585.
5. Chrubasik S, Zimpfer CH, Schutt U, Ziegler R. Effectiveness of Harpagophytum procumbens in the treatment of acute low back pain. Phytomedicine. 1996;3:1-10.
6. Chrubasik S, Junck H, Breitschwerdt H, Conradt C, Zappe H. Effectiveness of Harpagophytum extract WS 1531 in the treatment of exacerbation of low back pain: a randomized placebo-controlled, double-blind study. European Journal of Anaesthesiology. 1999;16:118-29.
7. Chrubasik S, Eisenberg E, Balan E, Weinberger T, Luzzati R, Conradt C. Treatment of low back pain exacerbations with willow bark extract: a randomized double-blind study. American Journal of Medicine. 2000;109:9-14.
8. Krivoy N, Pavlotzky E, Chrubasik S, Eisenberg E, Brook G. Effects of salicis cortex extract on human platelet aggregation. Planta Medica. 2000;67:209-212.
9. Chrubasik S, Model A, Black A, Pollak S. A randomized double-blind pilot study comparing Doloteffin and Vioxx in the treatment of low back pain. Rheumatology. 2003;42:141-148.
10. Chrubasik S, Kunzel O, Model A, Conradt C, Black A. Treatment of low back pain with a herbal or synthetic anti-rheumatic: a randomized controlled study. Willow bark extract for low back pain. Rheumatology. 2001;40:1388-1393.
11. Ginsberg F, Famaey JP. A double-blind study of topical massage with Rado-Salil. Ointment in mechanical low back pain. The Journal of International Medical Research. 1987;15:148-153.
12. Keitel W, Frerick H, Kun U, Schmidt U, Kuhlmann M, Bredehoorst A. Capsicum pain plaster in chronic non-specific low back pain. Arzneimtel Forschung. 2001;51.
13. Frerick H, Keitel W, Kuhn U, Schmidt S, Bredehorst A, Kuhlmann M. Topical treatment of chronic low back pain with a capsicum plaster. Pain. 2003;106:59-64.
14. Stam C, Bonnet MS, van Haselen RA. The efficacy and safety of a homeopathic gel in the treatment of acute low back pain: a multi-centre, randomized, double-blind comparative clinical trial. British Homeopathic Journal. 2001;90:21-28.