FDA medicated pet food CFR225

21 CFR Part 225 (current Good Manufacturing Practice for Medicated Feeds) applies when pet food contains a drug (e.g., nitarsone, decoquinate, lasalocid) for treatment/prevention of specific disease. Common medicated pet foods: (1) nitarsone-containing chicken feed historically (FDA banned in 2015); (2) Hills Prescription Diet j/d — contains high omega-3 doses considered drug-relevant; (3) Royal Canin Calm — contains alpha-casozepine at functional dose (not currently classified as drug by FDA but functionally relevant). Medicated pet food requirements: NADA-approved drug substance; Type A/B/C medicated feed license; manufacturing per CFR 225 GMP; label includes drug name, amount, indications, withdrawal period (if animal-derived products are food-relevant). The 2024 FDA guidance clarified that structure/function pet food claims (e.g., 'joint support') are NOT drug claims and do NOT require NADA — but disease treatment claims (e.g., 'treats OA pain') DO require NADA.