Butorphanol

Because of its κ-agonist activity, at analgesic doses butorphanol increases pulmonary arterial pressure and cardiac work.

Additionally, κ-agonism can cause dysphoria at therapeutic or supratherapeutic doses; this gives butorphanol a lower potential for abuse than other opioid drugs.

[10] As with other opioid analgesics, central nervous system effects (such as sedation, confusion, and dizziness) are considerations with butorphanol.

In veterinary anesthesia, butorphanol (trade name: Torbugesic) is widely used as a sedative and analgesic in dogs, cats and horses.

It is used for operative and accident-related pain in small mammals such as dogs, cats, ferrets, coatis, raccoons, mongooses, various marsupials, some rodents and perhaps some larger birds.

[15] It is administered either IM or IV, with its analgesic properties beginning to take effect about 15 minutes after injection and lasting 4 hours.

[16] It is also commonly paired with sedatives, such as xylazine and detomidine, to make the horse easier to handle during veterinary procedures.

Side effects specific to horses include sedation and CNS excitement (displayed by head pressing or tossing).