Botulinum Toxin A in Postherpetic Neuralgia

Abstract

Data confirm that BTX-A is effective and well tolerated in the treatment of PHN.

Botulinum toxin type A for neuropathic pain in patients with spinal cord injury

“…Therefore, it was difficult to determine the exact onset and duration of the effects of BTX‐A in patients with SCI‐associated neuropathic pain. Previous reports on BTX‐A injections for neuropathic pain have indicated that the onset of relief and duration of effectiveness were approximately 1 to 2 weeks and 3 to 6 months, respectively 9, 10, 11, 25. Our study showed that the effective duration was at least 8 weeks.…”

“…However, recent studies have reported that BTX‐A for the treatment of neuropathic pain can be administered subcutaneously or intradermally 9, 10, 11, 25, 26. The effects on pain may be mediated through direct effects on the sensory system 16.…”

“…In a previous case report of BTX for neuropathic pain in patients with spinal cord lesions, BTX‐A was administered subcutaneously; a subcutaneous route was chosen for this study 17. In most studies, the fractioned dosage of BTX‐A for the treatment of neuropathic pain was between 2.5 and 7.5U/cm 2 per painful surface area, and the maximum total dosage was between 100 and 200U 9, 10, 11, 25, 26, 27. In the present study, the painful surface area in patients with SCI was generally larger than that in patients with focal neuropathy such as postherpetic neuralgia and post‐traumatic neuropathy.…”

Toxina botulínica: uma nova opção para o tratamento da neuralgia pós-herpética?

“…2 Em indivíduos imunocomprometidos, embora possa apresentar-se inicialmente da forma habitual, o rash tende a ser mais grave e de duração prolongada, podendo se estender a grandes áreas. 2 A neuralgia pós-herpética (NPH), principal complicação do herpes-zóster, 3,4,5 consiste na persistência da dor por período superior a quatro meses após o início do desenvolvimento do rash cutâneo e ocorre em cerca de 10% dos pacientes. 1 Tem sua incidência aumentada em pacientes com idade avançada 1,2,4 na localização oftálmica da lesão de herpes-zóster.…”

“…O quadro pode evoluir para dor crônica, muitas vezes debilitante, havendo inclusive relatos de tentativas de suicídio em casos mais graves. 2,3,4 O mecanismo fisiopatológico da neuralgia envolve os neurônios aferentes (nociceptores), terminações nervosas especializadas que respondem a estímulos (térmicos, químicos ou mecânicos) de produção de dor. Através das fibras curtas (fibras C e A-∂), os nociceptores ativados são capazes de traduzir o estímulo recebido em estímulo elétrico e transmiti-lo do sistema nervoso periférico para o sistema nervoso central (SNC), onde será interpretado no córtex como dor.…”