Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .
Valaciclovir compared with acyclovir for improved therapy for herpes zoster in immunocompetent adults.
Acyclovir treatment of acute herpes zoster speeds rash healing and decreases pain and ocular complications . The limited oral bioavailability of acyclovir necessitates frequent dosing . Valaciclovir , the l-valyl ester of acyclovir , is rapidly and almost completely converted to acyclovir in vivo and gives three- to fivefold increases in acyclovir bioavailability . In a r and omized , double-blind , multicenter study , the safety and efficacy of oral valaciclovir given at a dosage of 1,000 mg three times daily for 7 or 14 days and oral acyclovir given at a dosage of 800 mg five times daily for 7 days were compared in immunocompetent adults aged > or = 50 years with herpes zoster . Patients were evaluated for 6 months . The intent-to-treat analysis ( 1,141 patients ) showed that valaciclovir for 7 or 14 days significantly accelerated the resolution of herpes zoster-associated pain ( P = 0.001 and P = 0.03 , respectively ) compared with acyclovir ;  median pain duration s were 38 and 44 days , respectively , versus 51 days for acyclovir . Treatment with valaciclovir also significantly reduced the duration of postherpetic neuralgia and decreased the proportion of patients with pain persisting for 6 months ( 19.3 versus 25.7 % ) . However , there were no differences between treatments in pain intensity or quality -of-life measures . Cutaneous manifestations resolved at similar rates in all groups . Adverse events were similar in nature and prevalence among groups , and no clinical ly important changes occurred in hematology or clinical chemistry parameters . Thus , in the management of immunocompetent patients > or = 50 years of age with localized herpes zoster , valaciclovir given at 1,000 mg three times daily for 7 days accelerates the resolution of pain and offers simpler dosing , while it maintains the favorable safety profile of acyclovir
Such interventions would have the potential to reduce the prevalence of chronic pain in the population .
Although certain risk factors can identify individuals who are most likely to develop chronic pain , few interventions to prevent chronic pain have been identified .
To facilitate the identification of preventive interventions , an IMMPACT meeting was convened to discuss research design considerations for clinical trials investigating the prevention of chronic pain .
We present general design considerations for prevention trials in population s that are at relatively high risk for developing chronic pain .