Proceedings for Pain Management and Humane Endpoints
Humane Endpoints for Laboratory Animals Used in Toxicity Testing
William S. Stokes, D.V.M.
National Institute of Environmental Health Sciences
Toxicity testing is conducted to identify the potential adverse health effects or to demonstrate the safety of new chemicals and products, thereby providing the basis for safeguarding human and animal health. Toxic effects in animals used in acute and chronic toxicity studies are often accompanied by clinical signs of pain and distress. In recent years there have been significant efforts to identify humane endpoints for toxicity studies that can be used as criteria for ending a test procedure to avoid or terminate pain and distress. New and revised test methods and approaches that incorporate humane endpoints are being considered and adopted by national and international regulatory testing authorities. Prerequisites for adoption of new and revised methods are a determination that the methods have been adequately validated, and that they will provide equivalent or better information for risk assessment. Recent examples of test methods where humane endpoints have been incorporated include those for acute oral toxicity, ocular and dermal irritation/corrosion, and dermal hypersensitivity. Details of these new and revised methods will be discussed. Further progress in eliminating pain and distress in toxicity testing is expected as advances in science and technology are incorporated into research and testing strategies.