Prevention of post-herpetic neuralgia: acyclovir and prednisolone versus epidural local anesthetic and methylprednisolone.

BACKGROUND: Treatment of herpes zoster (HZ) includes the use of acyclovir with or without steroids. An alternative therapy is the epidural administration of local anesthetics with or without steroids. This trial compared the efficacy of these two treatment regimens in the prevention of post-herpetic neuralgia (PHN).

METHODS: Six hundred adults over 55 years of age with a rash of less than 7 days duration, and severe pain due to HZ, were enrolled and randomized to receive either intravenous acyclovir (10 mg/kg three times daily) for 9 days+prednisolone (60 mg per day with progressive reduction) for 21 days, or 6-12 ml bupivacaine (0.25%) every 6-8 or 12 h+methylprednisolone 40 mg every 3-4 days by epidural catheter during a period ranging from 7 to 21 days. Efficacy was evaluated at 1, 3, 6 and 12 months. PHN was assessed as pain and/or allodynia, and "abnormal sensations" (hypoesthesia, burning, itching, etc.). Statistical analysis was performed based on the intent-to-treat population.

RESULTS: In the 485 patients who completed the study, the incidence of pain after 1 year was 22.2% (51 patients of 230) after acyclovir+steroids, and 1.6% (4 patients of 255) after epidural analgesia+steroids. The incidence of abnormal sensations was 12.2% (28 patients) after acyclovir+steroids, and 4.3% (11 patients) in group B.

CONCLUSIONS: Epidural administration of local anesthetic and methylprednisolone is significantly more effective in preventing PHN at 12 months compared to intravenous acyclovir and prednisolone.