FDA's Prohibited Drug List

Drugs prohibited from use in food-producing animals:

DES
Chloramphenicol
Nitroimidazoles (including metronidazole)
Nitrofurans (including topical use)
Clenbuterol
Dipyrone
Glycopeptides (example vancomycin)
Gentian violet
Phenylbutazone in adult dairy cattle*
Antiviral compounds in poultry (including adamantane and neuraminidase inhibitors)

Drugs prohibited from extralabel use in food-producing animals:

Sulfonamides in adult dairy cattle*
Fluoroquinolones
Medicated feeds
Indexed drugs (Exceptions may be made for minor species)

* Lactating (adult) dairy cattle are defined by FDA as dairy cattle 20 months of age or older regardless of whether they are milking or dry. Currently the only sulfonamide available for use in dairy cattle older than 20 months of age is sulfadimethoxine (SDM). In adult dairy cattle this drug may only be used on-label. Administering higher doses or sustained release SDM products is prohibited. Aside from the above AMDUCA list, regulations related to the Pasteurized Milk Ordinance (PMO) prohibit the presence of dimethyl sulfoxide (DMSO) and colloidal silver on dairies.