Practical use of opioids in cats: a state-of-the-art, evidence-based review.

RATIONALE: Recent recognition of the need to improve pain management in cats has led to the investigation of the pharmacokinetics and efficacy of opioid analgesic drugs in this species. The results of these studies may be difficult to interpret because the effect of these drugs varies with dose, route of administration and the method used to assess them. As equipotency of different opioids is not known, it is hard to compare their effects. Animals do not verbalise the pain they feel and, in cats, it may be more difficult to recognise signs of pain in comparison with other species such as dogs. AIM: This article reviews the use of opioid analgesics in cats. It must be remembered that not all drugs are licensed for use in cats, and that marketing authorisations vary between different countries. © ISFM and AAFP 2015.