Systematic overview of the pharmacological management of postherpetic neuralgia. An evaluation of the clinical value of critically selected drug treatments based on efficacy and safety outcomes from randomized controlled studies.

OBJECTIVE: This study systematically reviews current evidence on drug treatments commonly used in postherpetic neuralgia. METHODS: Randomized controlled trials were critically selected using predefined search criteria. Efficacy was evaluated as percentage of improvement in pain intensity between baseline and endpoint, tolerability by number of study discontinuations because of adverse events and incidence of adverse events. RESULTS: Currently published trials enrolled different patient populations and small patient numbers. The great variability in doses, titration schemes, designs and washout periods together with other design flaws made comparison between different studies scientifically impossible. CONCLUSIONS: There is a real need for well-performed clinical trials with standardization in design and reporting. Development of adequate and validated questionnaires for evaluation and comparison of efficacy and safety of treatments is also needed. Based on the evaluation of individual studies, it is concluded that only gabapentin is studied in large (over 200 patients), placebo-controlled studies showing good efficacy and safety.