Extended withdrawal time (EWDT) of drugs to prevent residues in food following extra label use

Abstract

Safety of food originated from animals is an emerging global health problem, and ensuring food safety is a challenge for the producers and governments who deal with protecting the food supply chain from contamination with hazardous microbes, chemicals and/or drugs. In the United States (US), the Food Animal Residue Avoidance Databank (FARAD) program is a unique consortium of scientific experts who help maintain a proper balance among animal health, food safety, and regulatory policies. Veterinarians must often use drugs in an extra-label manner to treat food animals due to limited availability of Food and Drug Administration (FDA) approved drugs. Extra-label drug use (ELDU) is allowable under the Animal Medicinal Drug Use Clarification Act (AMDUCA). Following ELDU, and before products derived from the treated animal can be sold and marketed, an extended withdrawal time (EWDT) needs to be established, based on appropriate scientific data. The objective of this paper is to discuss the scientific basis for determination of EWDT of drugs used in food animals using kinetic modeling approach.