Botulinum toxin A in postherpetic neuralgia: a parallel, randomized, double-blind, single-dose, placebo-controlled trial.
OBJECTIVE
Cumulative evidence support a beneficial effect of botulinum toxin A (BTX-A) in postherpetic neuralgia (PHN). We aimed to assess efficacy, safety, and tolerability of BTX-A in the management of PHN, performing a randomized, double-blind, single-dose, placebo-controlled trial.


METHODS
Thirty adults with PHN were randomized either to BTX-A or placebo. Severity of pain was evaluated by patients using a visual analogue scale (VAS) and quality of sleep was assessed using a 5-item questionnaire. Primary outcome was reduction in VAS score, with a greater than 50% reduction being considered clinically significant. Secondary outcomes were reduction in sleep score and maintenance of VAS score after treatment, with over 50% maintenance considered clinically meaningful.


RESULTS
Thirteen patients from the experimental arm achieved an at least 50% reduction in VAS score, compared with none of the placebo patients (NNT=1.2, 95% CI, 2-1; ARR=0.87, 95% CI, 055-096; P<0.001). BTX-A patients showed significant reduction in VAS pain scores between baseline and week 2, which persisted for a median period of 16 weeks. BTX-A patients showed significant reduction in sleep scores between baseline and week 2, which remained unchanged until 16th week (P<0.001). Treatment was well tolerated.


CONCLUSIONS
Data confirm that BTX-A is effective and well tolerated in the treatment of PHN.
*State Hospital for Dermatologic and Venereologic Diseases †First Department of Dermatology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
Zoe
Z
Apalla
Elena
E
Sotiriou
Aimilios
A
Lallas
Elizabeth
E
Lazaridou
Demetrios
D
Ioannides
D000368:Aged; D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D051474:Neuralgia, Postherpetic / Q000175:diagnosis* / Q000188:drug therapy*; D010147:Pain Measurement / Q000187:drug effects*; D015990:Placebo Effect; D016896:Treatment Outcome
D019274:Botulinum Toxins, Type A