Dowd N P, Day F, Timon D, Cunningham A J, Brown L
Department of Anesthesia and Pain Management, Beaumont Hospital, Dublin, Ireland.
J Pain Symptom Manage. 1999 Mar;17(3):175-80. doi: 10.1016/s0885-3924(98)00121-3.
The effect of iontophoretic administration of vincristine in the treatment of postherpetic neuralgia (PHN) was investigated in a prospective, double-blind, placebo-controlled trial. Twenty patients with intercostal or lumbar PHN for more than 6 months that was unresponsive to conventional medical therapy 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 the treatment period and were significantly lower on day 20 compared to baseline in both groups. Pain relief was described as moderate or greater in 40% of patients with vincristine and 55% of patients with placebo. There was no statistical difference an actual pain scores on day 20 between the two groups. Moderate or greater pain relief was maintained in 30% of patients with vincristine and 33% of patients with placebo at follow-up on day 90. We conclude that iontophoresed vincristine is no better than iontophoresed saline 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 possibly by related to a beneficial effect of iontophoresis.
