engleski

Botulinum toxin and pain

Objective: Botulinum toxin (BTX) is succesfully used in the managment of muscle over-activity. However, there are growing data that demonstrate the marked analgesic effect of BTX when used in the treatment of dystonia and spasticity. However our preliminary results show that the major benefit of BTX type-A treatment on pain reduction compared to dystonia improvment was the duration of action and the lower beneficial dose. This suggest that a direct antinociceptive effect distinc from muscle spasm reduction may be involved. To compare the effectiveness of different doses of BTX-A for the treatment of motor disability and pain associated with dystonia in patients with painful cervical dystonia.Methods: Thirty-eight patients with painful cervical dystonia were enrolled in a randomized, double blind, parallel group, and 3-month duration study. At baseline patients received an injection of BTX-A (BOTOX) in a range from 25 to 150 U. Clinical assessment and side effects were recorded from baseline until week 12. Primary efficacy parameters were the change from the baselin in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS), pain frequency, pain severity score. Secondary variables were physician and patinets's global assessment scale. Results Significant pain relief (p<0.01) was obtained in a patients treated with 50, 100, and or 150 U of BOTOX already one week after injection, while 25 U of BTX-A had no effect. On the contrary, TWSTRS-Total Score was significantly (p<0.01) decreased at 2 weeks post injections, but only in patients who were injected with higher doses of BTX-A (100 and 150 U). Thus, the smallest dose of BTX-A used had no effect on pain relief or distonia score, while 50 U of BOTOX was effective only for pain relief without any significant change in muscle activity and TWSTRS. In addition, with two higher BTX-A doses (100 and 150 U of BOTOX) pain relief was obtained one-week post injection, while it took 2 weeks for significant reduction in TWSTRS score.No systemic side effect were observed. Conclusion: This results appear to demonstrate for the first time the BTX-A may have a direct antinociceptive effect distinct from the influence upon the muscle-relaxing properties.

Botulinum toxin type A ; pain

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