Effects of Intravenous Prostaglandin E1 on Pain and Body Temperature in Patients with Post-Herpetic Neuralgia

Abstract

Bathing, heating, or sympathetic blockade often alleviates pain due to post-herpetic neuralgia (PHN), suggesting that blood flow may affect PHN pain. Here, we examined the effect of prostaglandin E1 (PGE), which improves blood circulation, on pain and body temperature in patients with PHN. Twenty-four patients with PHN were enrolled in a randomized, double-blind, placebo-controlled, crossover study. After 30-minute rest in a temperature-controlled (20 degrees C) and intravenous cannulation, patients were randomized to receive either 60 microg of PGE dissolved in 100 mL of saline, or 100 mL of saline at an infusion rate of 0.03 microg/kg/min. Following a 7-day washout period, patients were crossed over to receive the other treatment. The visual analog scale (VAS) of ongoing pain and tactile allodynia, and skin and the tympanic temperatures were measured before and after infusion. The two solutions significantly decreased the VAS for ongoing pain, and the reduction was greater with PGE than placebo (P < 0.05). Although the temperatures of the forehead, hand, foot, chest, abdomen, and the most painful region were significantly increased in the two solutions, the elevation in the foot and the most painful region was greater with PGE than placebo (P < 0.01). The tympanic temperature did not significantly change following infusion of PGE. Intravenous infusion of PGE produces analgesia associated with elevation of skin temperature in patients with PHN.