The certainty of evidence is downgraded due to serious risk of bias, serious inconsistency, serious imprecision, serious indirectness, serious publication bias (inadequate concealment of allocation during randomization process, resulting in potential for selection bias; point estimates vary widely; differences between the population of interest and those studied; mostly commercially funded studies).
Antivirals are suggested for patients with acute herpes zoster to prevent postherpetic neuralgia.
Rational: No plausible harms from a cheap and safe intervention. Values and preferences: Many patients would choose the intervention if there is a small chance of avoiding postherpetic neuralgia. Resources: Generic acyclovir is cheap.
A Cochrane review [PubMed] included 6 studies with a total of 1 211 immunocompetent patients. Rash of herpes zoster had been present for 72 hours or less. Five studies evaluated oral acyclovir at a dose of 800 mg 5 times daily for 7 to 21 days and one study (n=419) evaluated oral famciclovir 500 mg; famciclovir 750 mg; or placebo, 3 times daily for 7 days. One study randomised patients to acyclovir, prednisone, both acyclovir and prednisone, or neither acyclovir nor prednisone for 21 days. The follow-up time was 6 months in 5 studies and 5 months in one study. There was no significant difference between the oral acyclovir and control groups on the incidence of postherpetic neuralgia 4 months or 6 months (RR 1.05, 95% CI 0.87 to 1.27; 2 studies, n=476) after the onset of the acute herpetic rash. There was some evidence for a reduction in the incidence of pain 4 weeks after the onset of rash. Famciclovir 500 mg (RR 1.15, 95% CI 0.87 to 1.52; 1 study, n=284) or 750 mg (RR 1.31, 95% CI 1.01 to 1.71; 1 study, n=281) 3 times daily for 7 days did not reduce the incidence of herpetic neuralgia. No studies on valaciclovir were included.
Primary/Secondary Keywords