Are current therapies useful for the prevention of postherpetic neuralgia?

Kenneth E. Schmader, Stephanie Studenski

To determine whether current therapies are useful in preventing postherpetic neuralgia (PHN) by analysis of study designs and pooled results. Meta-analysis of all controlled studies investigating PHN prevention in the immunocompetent host. Articles were identified through MEDLINE, Index Medicus and bibliographic reviews of major texts and review articles. Studies meeting eligibility criteria were independently assessed using explicit methodologic criteria for validity and generalizability in clinical trials. Pooled analysis was also performed where appropriate. Twenty-one investigations met eligibility criteria and primarily addressed the use of antiviral agents and corticosteroids. Among studies with strong designs, no evidence of benefit was found for acyclovir or corticosteroids. Pooled results showed no significant effect of acyclovir on the prevention of PHN (odds ratio 0.81, 95% confidence interval 0.56, 1.11). The strongest studies that found potential efficacy in PHN prevention involved adenosine monophosphate and idoxuridine in dimethyl sulfoxide, but problems with clinical application limit the use of these compounds. Outcome definition, compliance assessment, power estimation, and method of randomization were infrequently addressed aspects of design. Currently there is no proven useful therapy for the prevention of PHN. The benefits of acyclovir and corticosteroids are limited but key questions remain regarding these medications. A clear consensus definition of PHN is needed to improve future investigations.