Topical acetylsalicylic acid versus lidocaine for postherpetic neuralgia: results of a double-blind comparative clinical trial.

A double-blind comparative clinical trial was performed with topical aspirin versus lidocaine for the treatment of 40 patients with postherpetic neuralgia. The percentage improvement following topical aspirin application was 72.2 +/- 19.9 S.D., while with lidocaine it was 72.8 +/- 25.3 S.D. These results suggest that the effect of topical treatment with aspirin is as good as that with lidocaine, since there was no significant difference (P = 0.778) between the two drugs in respect of pain reduction and accordingly the topical application of acetylsalicylic acid can be equally recommended.