The emphasis on providing humane care and good pain management to small animal patients has primarily focused on dogs, and
the pharmaceutical products available for use in that species. However, several analgesic and anesthetic products have recently
been developed and approved by the FDA-CVM for use in cats. Given the increased public awareness, increased client expectations
are impacting the care veterinarians are delivering to their feline patients. This lecture reviews some of the new products
and clinical studies focused on feline pain management and anesthesia.
Pain Management for Cats
Practitioners should develop a comprehensive, individualized practice program for recognizing and managing pain. Many recent
resources are available including journal articles and textbooks such as Lumb and Jones' Veterinary Anesthesia and Analgesia
(1, 2). The management of pain in cats differs from that in the dog due to species differences in drug and technique effectiveness
and toxicity of analgesic drugs including opioids and NSAIDs. Until recently, the only approved analgesic drug for cats was
butorphanol. This lead to nearly universal extralabel drug use and increased practitioner liability. Some pharmaceutical manufacturers
have responded to the need for approved feline products. Meloxicam (Metacam) and dexmedetomidine (Dexdomitor) have recently
been approved for use as analgesics in cats.
Dexmedetomidine (Dexdomitor) was approved in 2007 for use in cats as a sedative/analgesic. While medetomidine was used in
cats previously, this usage was extra-label. Building upon practitioner experience with Domitor, Dexdomitor is now approved
for use in cats (at a relatively low dose) to provide sedation and analgesia and to facilitate restraint for minor procedures.
While analgesia accompanies sedation, practitioners should not rely on alpha 2 agonists alone in any species for surgical
anesthesia. Local anesthetic blockade is recommended if surgical trauma is anticipated to prevent sudden arousal and defensive
behavior from the cat.
Cardiovascular effects of alpha 2 agonists are similar to those reported in dogs. Animals that cannot tolerate a decrease
in cardiac output, increase in vagal tone, or increase in systemic vascular resistance should not receive alpha 2 agonists.
Dexdomitor can be antagonized by intramuscular administration of atipamezole (Antisedan). Intravenous administration should
probably be reserved for emergency situations since antagonist induced rapid vasodilation in the presence of reduced sympathetic
tone can lead to precipitous hypotension. While Dexdomitor is now an approved label use, atipamezole reversal in cats is not
approved, although quite common.
Although meloxicam use in cats has been reported for several years, its use in the US was extra-label until 2004. Currently
Metacam is approved for postoperative analgesia in cats as a single subcutaneous dose of 0.3 mg/kg. Repeated administration
is not an approved label indication; however, several references discuss its use for multiple days (2). It should be remembered
that repeated dosing, especially at the higher label dose has been associated with renal dysfunction in cats. It would seem
prudent that repeated dosing be done with full informed consent of the owner with the goal of a careful dose titration to
the lowest effective dose.
Carprofen is approved for treatment of perioperative pain and osteoarthritis in dogs. It is not approved for use in cats within
the US although it has approved in a number of European countries for many years. Carprofen is effective in cats for control
of pain and inflammation; however there is considerable individual variation in the elimination of the drug (3). This can
result in accumulation of carprofen with repeated dosing in some cats resulting in toxicity including renal dysfunction and
possibly death. If Rimadyl is used, a single dose is preferable. If repeated dosing is attempted a careful individualized
safe dose interval should be determined.
Maropitant (Cerenia) has recently been approved for use in dogs as an antiemetic. It is an NK-1 receptor antagonists and appears
to interfere with emesis both peripherally and centrally. While not approved for use in cats, it has been used at the same
dose as recommended for dogs for the treatment of signs associated with renal failure and other metabolic diseases. Maropitant
can be useful for the prevention of emesis associated with opioid and anesthetic administration and should be considered when
vomition is contraindicated (e.g., corneal ulcer repair) or when anesthetic recovery is accompanied by significant nausea