Conclusion Based on the current evidence , BTX-A may be an effective and safe option for the treatment of neuralgia .
Aim This meta- analysis was performed to evaluate the efficacy and safety of botulinum toxin-A ( BTX-A ) for the treatment of neuralgia .
Safety and efficacy of repeated injections of botulinum toxin A in peripheral neuropathic pain (BOTNEP): a randomised, double-blind, placebo-controlled trial
BACKGROUND Data from previous studies suggest that botulinum toxin A has analgesic effects against peripheral neuropathic pain , but the quality of the evidence is low . We aim ed to assess the safety and efficacy of repeated administrations of botulinum toxin A in patients with neuropathic pain . METHODS We did a r and omised , double-blind , placebo-controlled trial at two outpatient clinics in France ( Clinical Pain Centre , Ambroise Paré Hospital , APHP , Boulogne-Billancourt , and Neurological Centre , Hôpital Dupuytren , Limoges ) and one in Brazil ( Neurological Department , Hospital das Clínicas da FMUSP , São Paulo ) . Patients aged 18 - 85 years with peripheral neuropathic pain were r and omly assigned ( 1:1 ) by block r and omisation , according to a central ised schedule , to receive two subcutaneous administrations of botulinum toxin A ( up to 300 units ) or placebo , 12 weeks apart . All patients and investigators were masked to treatment assignment . The primary outcome was the efficacy of botulinum toxin A versus placebo , measured as the change from baseline in self-reported mean weekly pain intensity over the course of 24 weeks from the first administration . The primary efficacy analysis was a mixed-model repeated- measures analysis in the intention-to-treat population . This trial is registered with Clinical Trials.gov , NCT01251211 . FINDINGS Between Oct 2 , 2010 , and Aug 2 , 2013 , 152 patients were enrolled , of whom 68 were r and omly assigned ( 34 per group ) , and 66 ( 37 [ 56 % ] men ) were included in the primary analysis ( 34 in  the botulinum toxin A group and 32 in the placebo group ) . Botulinum toxin A  reduced pain intensity over 24 weeks compared with placebo ( adjusted effect estimate -0·77 , 95 % CI -0·95 to -0·59 ; p<0·0001 ) . Pain on injection was the only adverse effect reported , and occurred in 19 ( 56 % ) participants in the botulinum toxin A group and 17 ( 53 % ) of those in the placebo group ( p=1·0 ) . Severe pain was experienced by ten ( 29 % ) participants in the botulinum toxin A group and 11 ( 34 % ) in the placebo group ( p=0·8 ) . INTERPRETATION Two administrations of botulinum toxin A , each of which comprised several injections , have a sustained analgesic effect against peripheral neuropathic pain . Several factors , such as the presence of allodynia and a limited thermal deficit , may be useful in predicting treatment response and should be investigated further . FUNDING Institut National de la Santé et de la Recherche Médicale ( INSERM ) and Fondation CNP ( France )
Conclusion Based on the current evidence , BTX-A may be an effective and safe option for the treatment of neuralgia .
Aim This meta- analysis was performed to evaluate the efficacy and safety of botulinum toxin-A ( BTX-A ) for the treatment of neuralgia .