Buprenorphine is a classified as a partial opioid agonist due to its affinity for the mu receptor and lack thereof for any other opioid receptors. Buprenorphine is unique in that it has a delayed onset of action, regardless of route of administration, but a long duration of action of about 6-12 hours.  It can be absorbed via the transmucosal route of administration in cats21.

Several formations are commercially available that extend the duration of action to 24 hours. Its affinity for the mu receptor is such that is difficult to reverse even with a complete antagonist such as naloxone. 

Buprenorphine is regarded as relatively “safe” as it has a ceiling effect wherein additional doses do not produce more effect. Compared to full agonist opioids, it cannot reach maximum clinical analgesic effect suggesting it is not adequate for severe pain22. Buprenorphine is currently used for the management of opioid dependence. It can be used under the tongue, by injection, as a skin patch or as an implant.