In dogs with thoracolumbar intervertebral disc extrusion, an intravenous injection of morphine does not affect the modified Frankel score after 30 min compared with the pre-injection value
Journal citation

Fouhety, A., Bruwier, A., Bassanino, J., et al (2020)
Effect of intravenous morphine injection on neurological examination of dogs with thoracolumbar intervertebral disk extrusion
Frontiers in Veterinary Science 7: 571778
Full text available

Published October 2020

Type of study
  • Prospective, blinded, randomised and placebo-controlled study
  • n = 62 dogs
Key points
  • Opioids are speculated to have an effect on the neurological examination and sometimes analgesia is delayed in acutely painful dogs until after the neurological examination as decisions on prognosis and surgical intervention are based upon the results of these
  • 62 dogs had a neurological examination followed by either injection of morphine (0.5mg/kg) i/v or placebo (saline solution). A second neurological examination was performed 30 minutes later
  • Deficits were graded using the modified Frankel score (MFS)
  • It was found that there was no difference between pre- and post-Frankel scores


  • Dogs that had received analgesic medication more than 12 hours before their neurological assessment were included and it was assumed that their effects would be similar on the 2 examinations
  • All neurological grades were not equally represented in this study
  • These results support the immediate use of an analgesic dose of morphine in this population of dogs if the neurological examination can be performed 30 minutes or more after the injection