21 CFR § 530.41 - Drugs prohibited for extralabel use in animals.
(a) The following drugs, families of drugs, and substances are prohibited for extralabel animal and human drug uses in food-producing animals.
(3) Diethylstilbestrol (DES);
(6) Other nitroimidazoles;
(9) Sulfonamide drugs in lactating dairy cattle (except approved use of sulfadimethoxine, sulfabromomethazine, and sulfaethoxypyridazine);
(10) Fluoroquinolones; and
(12) Phenylbutazone in female dairy cattle 20 months of age or older.
(13) Cephalosporins (not including cephapirin) in cattle, swine, chickens, or turkeys:
(i) For disease prevention purposes;
(ii) At unapproved doses, frequencies, durations, or routes of administration; or
(iii) If the drug is not approved for that species and production class.
(b) The following drugs, families of drugs, and substances are prohibited for extralabel animal and human drug uses in nonfood-producing animals: [Reserved]
(d) The following drugs, or classes of drugs, that are approved for treating or preventing influenza A, are prohibited from extralabel use in chickens, turkeys, and ducks:
(2) Neuraminidase inhibitors.