A systematic review and meta-analysis found that subcutaneous injections of botulinum toxin type A (BTX-A) effectively decreased peripheral neuropathic pain. These findings were published in the European Journal of Pain.
Investigators at the Hôpital Raymond Poincaré in France searched publication databases through June 2021 for randomized clinical trials of BTX-A injection for the treatment of neuropathic pain compared with placebo. A total of 10 trials published between 2005 and 2021 met the inclusion criteria.
The total evaluated population consisted of 530 patients with neuropathic pain associated with postherpetic, posttraumatic, postsurgical, or diabetic polyneuropathy etiologies. Patients received multiple injections covering the site of pain with total doses of 5 to 300 U. The mean follow-up time was 11.96 weeks.
Pain intensity was significantly lower among BTX-A recipients at 1 (mean difference [MD], -1.87; 95% CI, -2.91 to -0.83; I2, 90%) and 3 (MD, -1.38; 95% CI, -1.95 to -0.81; I2, 0%) months.
In a subgroup analysis, BTX-A was most effective among patients with diabetic polyneuropathy (MD, -2.48; 95% CI, -3.22 to -1.74; I2, 35%) but not effective for postherpetic neuralgia (MD, -2.29; 95% CI, -6.21 to 1.63; I2, 98%) or posttraumatic or postsurgical neuralgia (MD, -0.74; 95% CI, -1.54 to 0.06; I2, 0%).
Stratified by pain symptoms, BTX-A was effective for treating burning sensations (MD, -3.05; 95% CI, -3.98 to -2.11), unpleasant sensations (MD, -2.97; 95% CI, -4.53 to -1.41), deep pain (MD, -2.85; 95% CI, -4.22 to -1.48), sensitivity sensations (MD, -2.57; 95% CI, -4.30 to -0.83), and paroxysmal pain (MD, -1.60; 95% CI, -2.80 to -0.39).
Little evidence supported an improvement in sleep scores after BTX-A treatment.
The most common adverse event was injection site pain lasting no more than 24 hours (risk ratio [RR], 0.99; 95% CI, 0.89-1.10; P =.86; I2, 0%).
This analysis was limited by the quality of the underlying data, which for the most part, were sourced from small, single-center studies.
This review found evidence to support BTX-A subcutaneous injections for reducing intensity of neuropathic pain, with BTX-A being most effective for diabetic polyneuropathy and burning pain symptoms.
Hary V, Schitter S, Martinex V. Efficacy and safety of botulinum A toxin for the treatment of chronic peripheral neuropathic pain: A systematic review of randomized controlled trials and meta-analysis. Eur J Pain. 2022;26(5):980-990. doi:10.1002/ejp.1941