Postherpetic Neuralgia: Impact of Famciclovir, Age, Rash Severity, and Acute Pain in Herpes Zoster Patients

Abstract

New and previously reported analyses of the data from a placebo-controlled trial of famciclovir are reviewed in light of recently proposed recommendations for the analysis of pain in herpes zoster trials. The analyses examined the effect of famciclovir treatment on the duration of postherpetic neuralgia (PHN), which was defined as pain persisting after rash healing, pain persisting > 30 days after study enrollment, or pain persisting > 3 months after study enrollment; the baseline characteristics of patients in the famciclovir and placebo groups who developed PHN; the impact of famciclovir treatment on the duration of PHN, while controlling for significant covariates; and the prevalence of PHN at monthly intervals from 30 to 180 days after enrollment. The results of these analyses indicated that greater age, rash severity, and acute pain severity are risk factors for prolonged PHN. In addition, they demonstrated that treatment of acute herpes zoster patients with famciclovir significantly reduces both the duration and prevalence of PHN.

Zoster-Associated Pain and Post Herpetic Neuralgia

“…PHN, on the other hand, has been extensively investigated in different settings and a great deal of information is now available. PHN has been repeatedly associated with older age (Dworkin & Portenoy, 1996;Choo et al, 1997,;Dworkin et al, 1998;Decroix et al, 2000;Opstelten et al, 2002;Kurokawa et al, 2002;Scott et al, 2003;Jung et al, 2004;Volpi et al, 2008;Parruti et al, 2010;. Some decades ago, Hope-Simpson already envisaged this association observing his own HZ outpatients (Hope-Simpson, 1975), and in the following years older age has been one of the factors more frequently associated in almost all studies where it was investigated.…”

“…ZAP gained due attention only recently, even though pain at presentation was assessed in most of trials and cohorts on HZ and PHN (Dworkin et al, 1998;Chidiac et al, 2001;Dworkin et al, 2001). Acute pain at HZ presentation is rated as severe in a consistent proportion of patients (25%, 41%, 70%, …) and has been addressed for its impact on quality of life (Chidiac et al, 2001;Dworkin et al, 2001).…”

“…Some decades ago, Hope-Simpson already envisaged this association observing his own HZ outpatients (Hope-Simpson, 1975), and in the following years older age has been one of the factors more frequently associated in almost all studies where it was investigated. Indeed several cohort studies (Choo et al, 1997, Dworkin et al, 1998Decroix et al, 2000;Opstelten et al, 2002;Kurokawa et al, 2002;Scott et al, 2003;Jung et al, 2004;Volpi et al, 2008;Parruti et al, 2010; found significantly older age in patients developing PHN, in samples up to 1,900 patients. The SPS placebo arm, as well, provided evidence as to the predictive role of older age: enrolled subjects were stratified in two subgroups (60-69 years and ≥70 years), and PHN incidence in the 19,247 subjects was 0.74 cases/1,000 person-years in the first subgroup and 2.13 cases/1,000 person-years in the older (Oxman et al, 2005).…”

The Current Treatment and Prevention of Post Herpetic Neuralgia

“…These agents reduce the duration of viral shedding, hasten rash healing, reduce the severity and duration of acute pain, and reduce the risk of progression to PHN [39]. For example, Dworkin et al [40] and Parruti et al [41] done a cohort study of 419 and 519 Hz patients respectively found that patients receiving antiviral therapy in the acute phase had a significantly lower prevalence of PHN.…”

Association of HLA-A*3303-B*4403-DRB1*1302 haplotype, but not of TNFA promoter and NKp30 polymorphism, with postherpetic neuralgia (PHN) in the Japanese population

“…The outcomes of this pain include fatigue, sleep disturbance, anorexia, depression and impaired activities in daily living. 6,8 Although greater age, vesicular eruption severity and acute herpes zoster severity are considered as risk factors for prolonged PHN, 9 the genetic factors and immunological factors involved in its onset have not been clarified.…”