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 .
Antiviral therapy for herpes zoster: randomized, controlled clinical trial of valacyclovir and famciclovir therapy in immunocompetent patients 50 years and older.
OBJECTIVE To compare the efficacy and safety of valacyclovir hydrochloride and famciclovir for the treatment of  herpes zoster .  DESIGN A double-blind , r and omized , controlled , multicenter clinical trial in which patients received 7 days of treatment and were followed up for 24 weeks . SETTING S Patients reported directly to specialist centers or were referred from primary care centers . PATIENTS There were 597 otherwise healthy immunocompetent out patients , aged 50 years and older , who presented within 72 hours of onset of zoster rash . INTERVENTIONS Treatment with valacyclovir hydrochloride ( 1 g 3 times daily ) or famciclovir ( 500 mg 3 times daily ) for 7 days . MAIN OUTCOME MEASURES Resolution of zoster-associated pain and postherpetic neuralgia , rash healing , and treatment safety . RESULTS Intent-to-treat analysis did not detect statistically significant differences for valacyclovir vs famciclovir on resolution of zoster-associated pain ( hazard ratio , 1 . 02 ; 95 % confidence interval , 0.84 - 1.23 ; P = .84 ) . Furthermore , no differences were evident between treatments on rash healing rates and on a range of analyses of postherpetic neuralgia . Safety profiles for valacyclovir and famciclovir were similar , with headache and nausea being the more common adverse events . CONCLUSIONS Valacyclovir treatment is comparable to famciclovir treatment in speeding the resolution of zoster-associated pain and postherpetic neuralgia . Current wholesale prices indicate that valacyclovir is the more cost-effective treatment for herpes zoster ( $ 83.90 vs $ 140.70 per course )
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 .