Proceedings for Pain Management and Humane Endpoints

Alleviation of Pain in Laboratory Animals

Paul Flecknell, VETMB, PhD, DLAS, MRCVS
Comparative Biology Centre, Medical School, University of Newcastle, UK

Successful alleviation or prevention of pain in laboratory animals is critically dependent upon three factors: the accurate assessment of the degree of pain experienced, or likely to be experienced, by an animal; the implementation of effective methods of pain control; the integration of pain control measures with specific research protocols. This presentation will deal primarily with available methods of pain control and their implementation, and with the potential interactions of pain control and research protocols. Control of acute pain can be achieved relatively easily in most mammalian species by use of analgesics agents (opioids, NSAIDs, local anaesthetics), administered by a variety of routes (eg parenterally, intrathecally, epidurally). It is becoming generally accepted that use of analgesics of different classes in combination can provide more effective pain relief than when using any single agent alone. This concept can be termed "balanced analgesia" and has similar advantages to balanced anaesthesia, in that lower doses of individual compounds are administering, so achieving the desired effect with minimal undesirable side-effects. It is also widely accepted that administering analgesics before any noxious stimulus (eg surgery) occurs can reduce the degree of post-procedure pain. Although application of these approaches is often successful, there is still little information concerning interactions between analgesic regimens and analgesics, and almost no information concerning appropriate analgesics and dose rates for use in non-mammalian species. Concern still exists that administration of analgesics could interfere with the aims of some research protocols because of specific or non-specific drug effects. This concern is genuine, but it must be addressed logically, and the potential effects of analgesics placed in the context of all of the sources of variation in a study. Although this often allows effective use of analgesics to control acute pain, use of analgesics to control chronic pain presents much greater problems, and in these instances, use of non-pharmacological techniques my be more appropriate.

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