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U.S. Department of Health and Human Services

Animal & Veterinary

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FDA Permits Extralabel Drug Use Under Certain Conditions

FDA Veterinarian Newsletter 2006 Volume XXI, No III

Veterinarians have the right to prescribe the “extralabel” use of drugs beyond the approvals indicated on the label, under a rule that went into effect about 10 years ago, but the Food and Drug Administration (FDA) places limits the extralabel use of drugs to protect public health.

The final rule about extralabel use of veterinary drugs, which went into effect in December 1996, was authorized by the Animal Medicinal Drug Use Clarification Act (AMDUCA) of 1994. Prior to AMDUCA, veterinarians were not legally permitted to use an animal drug in any way except as indicated on the label.

A drug is used extralabelly in an animal if the drug’s actual or intended use is in a manner not in accordance with the approved labeling. For instance, a drug is being used extralabelly if it is used or intended to be used:

  • To treat a species not listed on the label;
  • For an indication, disease or other condition, not on the label;
  • At a dosage level or frequency not on the label; or
  • With a route of administration not on the label.

The extralabel use rule allows veterinarians to legally go beyond label directions in using animal drugs, and permits them to use legally obtained human drugs in animals. However, the rule does not permit extralabel use of a drug in or on animal feed. Further, drugs cannot legally be used extra-labelly except by, or on the order of, a veterinarian.

In addition, the prescribing veterinarian must be operating within a valid veterinarian-client-patient relationship, which means that the veterinarian must have firsthand knowledge of the animal being treated and will advise the owner on steps necessary, in the case of a food animal, to ensure a sufficient withdrawal period (the period after the last time the drug is administered and before any meat, milk, eggs, or other food product is marketed from the treated animal) for the drug.

Veterinarians are limited in using drugs extralabelly to cases in which the health of the animal is threatened, or suffering or death may result from a lack of treatment. Veterinarians cannot legally use drugs extralabelly to enhance production.

Also, veterinarians can consider using drugs extralabelly in food-producing animals only when no approved drug is available for use that contains the same active ingredient in the required dosage form and concentration, or that the veterinarian finds that the approved drugs are not clinically effective for their intended use.

In addition, the veterinarian must:

  • Make a careful diagnosis or evaluation of the conditions to be treated;
  • Establish a substantially extended drug withdrawal period that is supported by scientific evidence;
  • Take the steps necessary to be sure the withdrawal period is met and no illegal drug residues occur in food from the treated animals; and
  • Institute procedures to make sure the treated animal’s identity is known.

The regulation also places requirements on the veterinarian to properly label the drugs used extralabelly to give the livestock owner complete instructions about proper use of the drug and withdrawal times, and to identify the veterinarian who prescribed the drug.

Under no circumstances can a non-veterinarian order the extralabel use of a drug in animals.

Prohibited from extralabel use

AMDUCA also gives FDA the right to prohibit the use of certain drugs from extralabel use.

FDA can prohibit extralabel use of drugs if no acceptable analytical method for determining tissue residues has been established, or the use of the drug or class of drugs presents a risk to public health.

The prohibition can be against all uses of a drug, or against the use in limited species, or for certain indications, dosages, forms, routes of administration, or a combination of factors.

The list currently includes:

  • Chloramphenicol
  • Clenbuterol
  • Diethylstilbestrol
  • Dimetridazole
  • Furazolidone, nitrofurazone, other nitrofurans
  • Fluoroquinolones
  • Glycopeptide
  • Ipronidazole
  • Other nitroimidazoles
  • Phenylbutazone animal and human drugs in female dairy cattle 20 months of age or older
  • Sulfonamide drugs in lactating dairy cattle (except approved use of sulfadimethozine, sulfabromomethazine, and sulfaethoxpyridazine

These drugs, or classes of drugs, are prohibited from use in chickens, turkeys, and ducks:

  • Adamantanes
  • Neuraminidase inhibitors