Effects of Harpagophytum procumbens LI 174(devil's claw) on sensory, motorund vascular muscle reagibility in the treatment of unspecific back pain

Problem. This randomised, double-blind, placebo controlled study was intend ed to investigate the effects of Harpagophytum procumbens (Devil's Claw) on sensory, motor and vascular mechanisms of muscle pain. In addition to clin ical efficacy and tolerability, possible action mechanisms were analysed by means of experimental algesimetric methods. Methodology. The study was performed an patients with slight to moderate mu scular tension or slight muscular pain of the back, shoulder and neck. On a double-blind randomised basis the verum group received 2x1 film tablets pe r day, i.e. 2x480 mg/day, of Harpagophytum extract LI 174 (Rivoltan(R)) at 8.00 a. m. and 8.00 p. m. over a certain period. The duration of the therap y was 4 weeks. Data recording at 14-day intervals was made using a visual a nalogue scale, pressure algometer test, recording of antinociceptive muscul ar reflexes, muscle stiff ness test, EMG surface activity, muscular ischaem ia test, clinical global score and subjective patient and physician ratings . Results. A total of 31 patients in the verum group and 32 in the placebo gr oup were treated. After four weeks of treatment there was found to be a cle ar clinical efficacy of the verum on the clinical global score and in the p atient and physician ratings. Highly significant effects were found in the visual analogue scale, the pressure algometer test, the muscle stiffness te st and the muscular ischaemia test. No difference from placebo was found in the recording of antinociceptive muscular reflexes or in the EMG surface a ctivity. Tolerability was good; no serious adverse effects occurred. Conclusions. A highly significant clinical efficacy was achieved with a mon otherapy of Harpagophytum dry extract LI 174 after four weeks' treatment at a dosage of 2x480 mg/day in cases of slight to moderate muscular pain. Wit h regard to the action mechanisms investigated, it may be concluded that tr eatment with Harpagophytum extract LI 174 may be, expected to have a signif icant influence on sensory and vascular muscular response and bring about a reduction in muscle stiffness. No central nervous effects were discovered.