Iontophoretic administration of indomethacin (IND) was applied to investigate its effect in 21 cases of postherpetic neuralgia (PHN), which showed no response to other treatment such as nerve blocks. Iontophoretic therapy of IND was applied for 20 minutes once a week up to 5 time (series 1). When pain relief was unsatisfactory in series 1, the same treatment was given once again (series 2). Long term follow-up results were obtained 3 months after the final treatment in series 1 or 2. We used visual analog scale (VAS) to measure their pain intensity. VAS was reduced clearly at the end of the treatment in each series. The average improvement rate of the VAS in each series was as follows; series 1:60.3 +/- 8.2%, series 2:73.7 +/- 7.0%, long term follow-up

Results: 73.7 +/- 7.0% (mean +/- S.E.) We concluded from the present results that iontophoretic administration of IND was one of the effective and useful treatments for PHN.