Effect of intrathecal dexmedetomidine on spinal morphine analgesia in patients with refractory cancer pain

Abstract

Background: Systemic administration of dexmedetomidine has been shown to reduce opioid consumption and improve analgesia satisfaction. The purpose of this study was to investigate the effect of intrathecal dexmedetomidine on spinal morphine analgesia in patients with refractory cancer pain.

Methods: A double-blinded crossover study was designed and performed. Patients were randomly allocated in one of the two phases. Phase M received intrathecal morphine administration. Phase M+D received intrathecal morphine plus dexmedetomidine administration. All patients were monitored for 7 days and crossed over to alternate phase for another 1-week observation. Daily average visual analog scale (VAS) pain score, pain frequency, sleep deprivation, daily morphine consumption, bolus dose injection times, and side effects were all recorded.

Results: Pain intensity and frequency were significantly decreased in both phases compared with baseline. Daily morphine consumption and bolus dose injection times during phase M+D were significantly decreased compared with phase M. The incidences of constipation were significantly reduced in both phases compared with baseline administration, but nausea and vomiting were significantly increased. No serious side effects such as respiratory inhibition were observed in this study.

Conclusions: Intrathecal administration of dexmedetomidine and morphine reduced the morphine consumption in patients with refractory cancer pain. There were no serious side effects.