possesses NMDA receptor antagonist activity is ketamine, which, because of its
psychogenic properties, is no longer used in humans. It is, however, still widely
used in veterinary medicine as an anaesthetic induction agent. Use of this agent in
animals is common as a component of multimodal analgesic strategies for preven-
tion or reduction of post-operative neuropathic pain (Kohrs and Durieux 1998 ).
5 Conclusions
Elucidation of pain mechanisms and pathways and the use of analgesic drugs in
animals have followed similar developments in humans. However, the use of
laboratory animals and the development of models of pain in larger species have
facilitated advances in studies of human pain and hence also the treatment of animal
pain (Livingston 2003 ). The principal groups of analgesic drugs available for pain
relief in animals are similar to those available for humans. Thus, opioids, NSAIDs
and other analgesics such as tramadol used for treatment of neuropathic pain are
generally used on the basis of human experience. However, there are some classes
of analgesics, such as the alpha 2 adrenergic agonists, which have been developed
mainly for veterinary use.
In human medicine, there is increasing focus on a range of factors which may
influence pain perception, such as gender and race (Keogh and Herdenfeldt 2002 ),
as well as other genetic factors. Similarly, other sensory factors which may influ-
ence mood or perception are thought to be able to influence the level of pain
perceived (Rhudy and Meagher 2000 ). In veterinary medicine the biggest chal-
lenges are the implication of chronic pain for animal welfare in farmed animals
(Mellor and Stafford 2004 ), the extension of surgical and other treatments for
cancer to pet animals (Carsten et al. 2008 ) and recognition of the need for analgesic
strategies in non-mammalian species (Mosley 2005 ). Therefore, although there are
many similarities in the treatment of pain in humans and animals, there will always
be some differences in approach. There are now many reports of different analgesic
drugs, being used in a range of animal species; this chapter has focussed on the
more common and better reported uses.
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