Iontophoretic vincristine in the treatment of postherpetic neuralgia: A double-blind, randomized, controlled trial

The effect of iontophoretic administration of vincristine in the treatment of postherpetic neuralgia (PHN) was investigated in a prospective, double-b lind placebo-controlled trial. Twenty patients with intercostal or lumbar P HN for more than 6 months that was unresponsive to conventional medical the rapy were randomized to receive vincristine 0.01 % (n = 11) or saline (n = 9), by iontophoresis over 1 hour daily for 20 days. Demographics and median duration of pain were similar in both groups. Pain scores decreased over t he treatment period and were significantly lower on day 20 compared to base line in both groups. Pain relief was described ns moderate or greater in 40 % of patients with vincristine and 55% of patients with placebo. There was no statistical difference in actual pain scores an day 20 between the two g roups. Moderate or greater pain relief was maintained in 30 % of patients w ith vincristine and 33 % of patients with placebo at follow-up on day 90. W e conclude that iontophoresed vincristine is no better than iontophoresed s aline in the treatment of PHN. The maintained improvement in both groups at 3 months follow-up may reflect the natural history of PHN, or might possib ly be related to a beneficial effect of iontophoresis. J Pain Symptom Manag e 1999;17:175-180. (C) U.S. Cancer Pain Relief Committee, 1999.