From Dog

Morphine is a potent opioid analgesic used in canine patients with long-term painful conditions such as osteoarthritis or following acute orthopedic surgery.

It exerts its effects through both μ-receptors and serotonergic receptors within the brain[1].

Newer drugs such as buprenorphine have replaced its use in canine medicine.

Side-effects have been reported in multi-drug sensitivity breeds such as the Collie. As well, severe pruritus and myoclonus have been reported following intrathecal morphine administration[2].

Recommended dose rate in dogs is 0.1 to 0.25 mg/kg intramuscular or subcutaneous every 3 to 4 hours.


  1. Adriaens AM et al (2012) The Influence of Morphine on Cerebral 5-HT2A Availability in Dogs: a SPECT Study. J Nucl Med Oct 22
  2. Iff I et al (2012) Severe pruritus and myoclonus following intrathecal morphine administration in a dog. Can Vet J 53(9):983-986