Therapeutic Research

Abstract

Objectives：This study aimed to examine the efficacy of duloxetine, an adjuvant analgesic agent, in management of persistent pain caused by cancer itself.Material and Methods：Eighteen cancer patients, who complained of pain caused by cancer itself judged from the findings of CT/MRI imaging, were retrospectively analyzed. There was no patient with chemotherapy –induced neuropathic pain in this study. The effect of daily administration of duloxetine on pain relief was assessed using the 5 –point（0–4）verbal rating scale（VRS）. All patients complained of persistent cancer pain with the VRS scores greater than 2 before administration. Duloxetine was judged as effective when the VRS scores improved greater than 2 levels to achieve the VRS scores 0 or 1. Results：Analgesic effect was obtained in 14cases （77.8％）.The VRS score was 3.0 in average before administration and decreased to 0.71, 0.23 and 0.18 on day2, 3and7 post –administration. Duloxetine had analgesic effect at a dose of 20mg/day and pain relief was obtained from the initial administration. It was effective for all 11 cases with neuropathic pain, and 3 out of 7 cases with nociceptive pain. Side effects were observed in 7 patients, including nausea, sleepiness, fatigue and headache. Conclusions：Although we cannot exclude a placebo effect of duloxetine for its early effects post – administration, duloxetine is effective for persistent cancer pain. In contrast to the previous studies evaluating its analgesic effect after weeks of administration, our findings indicate that its effect is obtained within several days post –administration.