Loren Schultz, DVM, MS, University of Missouri, says FDA approval of an antibiotic requires manufacturers to demonstrate that the drug is safe and efficacious for its intended purpose in its intended species. Any variation from the label including dosage, dosing interval, or disease treated is considered extralabel use.

Speaking at the 2010 Western Veterinary Conference, Schultz said that veterinarians can use antibiotics in an extralabel manner; however restrictions to that use are imposed when prescribing products to food producing animals. In addition some products are illegal for use in food producing animals regardless of the veterinarian’s judgment. Extralabel use can only be done after following certain guidelines, such those outlined by the AVMA in its Extralabel Drug Use (ELDU) algorithm

Schultz stressed that In order for veterinarians to use a drug in this manner, first they must determine: Does a drug labeled for food animals exist which fulfills all of the following:

  • Contains the needed ingredient
  • In the proper dosage form
  • Labeled for the indication
  • And is clinically effective?

If the answer is yes, then the drug must be use as per label directions; if no, then the following question should be asked: Is there a drug approved for food animals which could be used extralabelly? If the answer is yes, the drug can be used extralabelly following these guidelines listed below.

Requirements for extra-label drug use

  • Permitted only under the supervision of a veterinarian
  • For FDA approved human and animal drugs
  • Valid veterinarian/client/patient relationship
  • Therapeutic use only
  • Rules apply to dosage form drugs administered in water
  • Prohibited in feed
  • Prohibited if it results in violative food residue
  • FDA prohibition of a specific extralabel drug use precludes use

Medical record requirements

  • Identify animal or group of animals
  • Species identification
  • Number of animals treated
  • Conditions being treated
  • Established name of the drug and active ingredient
  • Dosage prescribed or used
  • Duration of treatment
  • Specified withdrawal, withholding, or discard time for meat, milk, eggs, or animal-derived food
  • Keep records for two years
  • FDA may have access to records to estimate public health risk

Drug label requirements

  • Name and address of the prescribing veterinarian
  • Established name of the drug
  • Directions for use including species or identification of the animal or herd, flock pen, lot, or other group; dosage frequency; route of administration; and the duration of therapy
  • Cautionary statements
  • Specified withdrawal, withholding, or discard time for meat, milk, eggs, or any other food

Drugs prohibited for extralabel use

  • Chloramphenicol
  • Clenbuterol
  • Diethylstilbestrol
  • Dimetridazole
  • Ipronidazole
  • Other nitroimidazoles
  • Furazolidone, nitrofurazone, and other nitrofurans including topical sulfonamides in lactating dairy cattle (except approved use of sulfadimethoxine, sulfabromomethazine, and sulfamethoxypyridazine)
  • Fluoroquinolones
  • Glycopeptides
  • Phenylbutazone in female dairy cattle 20 months of age and older
  • Adamantane and neuraminidase inhibitor classes of drugs approved for use in treating influenza A are prohibited for use in chickens, turkeys, and ducks.