Guidelines for the Assessment and Management of Pain in Rodents and Rabbits

The assessment and management of pain in humans and animals has generated unprecedented discussion in the last 20 y. In the veterinary field, heightened awareness to pain has prompted several professional organizations to make formal position statements which unequivocally mandate pain relief.24 Regulatory bodies primarily concerned with the use of animals in biomedical research and teaching have also had an increased interest in pain and on July 10, 2003 the USDA’s Animal and Plant Health Inspection Service (APHIS) published a Federal Register notice calling for comments on the definition and reporting of pain and distress in animals under the Animal Welfare Act. While there is much discussion on the continuum of stress, distress and pain in animals, there is little agreement on delineation of crossover points for these apparently overlapping sensations. In addition, there is no agreed objective measure which can be used to reliably identify pain in animals and its severity. Further and more difficult, is the assessment of different types of pain. For example, while there is an intuitive predilection to consider “real” pain as physical pain, several studies suggest psychological distress can also adversely affect animal welfare.24 Semantics aside, it is generally agreed that pain adversely impacts the welfare of animals and that in research protocols, pain, if not controlled, is a variable which can confound the interpretation of experimental results. A position statement of the American College of Laboratory Animal Medicine (ACLAM) declares that “Procedures expected to cause more than slight or momentary pain (for example, pain in excess of a needle prick or injection) require the appropriate use of pain-relieving measures unless scientifically justified in an approved animal care and use protocol”(http://www.aclam.org/pub_pain_distress.html). The responsibility to relieve pain in animals used in research is consistent with the generally accepted view of the moral responsibility of humans towards animals; with the opinion of the public, whose support for the use of animals in research declines as the pain experienced by these animals increases;19 with relevant legislation (AWA, PHS); and with the goals of scientific research. This paper presents an overview of current concepts of pain and provides recommendations for the assessment, prevention and treatment of pain in rodents and rabbits. Also provided are guidelines for developing pain management protocols, tables describing the potential physiologic effects of some analgesic classes and examples of efficacious analgesic strategies.