The Animal Medicinal Drug Use Clarification Act of 1994 (AMDUCA) provides veterinarians acting within a veterinarian-client-patient relationship (VCPR) with greater prescribing and dispensing options so that animals can receive the medications they need when they need them. This is critical given the relatively few numbers of drugs labeled for use in animals
Extralabel drug use (ELDU) is the term that describes the use of an approved drug in a manner that differs in any way from the drug's approved labeling. This includes deviations from FDA-approved labeling such as using the drug in any of the following ways.
- In a species not listed on the label
- For an indication not listed on the label
- At a different dose or frequency than listed on the label
- Via a different route of administration than listed on the label
Keep in mind that AMDUCA does not give veterinarians "carte blanche" for ELDU.
- AMDUCA allows ELDU only on the lawful order of a licensed veterinarian in the context of a valid veterinarian-client-patient relationship.
- ELDU is limited to circumstances when the health of an animal is threatened, or suffering or death may result from failure to treat.
- U.S. Food and Drug Administration (FDA) regulations addressing ELDU are covered in 21 CFR 530.
- FDA maintains a list of drugs that are prohibited for ELDU for food-producing animals (21 CFR 530.41).
Food animals & ELDU of an approved animal drug
The following conditions must be met for a permitted extralabel use in food-producing animals of approved new animal and human drugs.
- There is no approved animal drug labeled for the use and containing the same active ingredient in the required dosage form and concentration, except where a veterinarian finds, within the context of a valid VCPR that the approved drug is clinically ineffective for its intended use.
- Prior to prescribing or dispensing an approved animal or human drug for an extralabel use in food animals, the veterinarian must do all of the following.
- Make a careful diagnosis and evaluation of the conditions for which the drug is to be used.
- Establish a substantially extended withdrawal period prior to marketing of milk, meat, eggs, or other edible products supported by appropriate scientific information, if applicable. The Food Animal Residue Avoidance Databank (FARAD) is a vital resource to help veterinarians accomplish this essential step.
- Institute procedures to assure that the identity of the treated animal or animals is carefully maintained.
- Take appropriate measures to assure that assigned timeframes for withdrawal are met and no illegal drug residues occur in any food-producing animal subjected to extralabel treatment.
Food animals & ELDU of an approved human drug or of an animal drug approved only for use in animals not intended for human consumption
The following additional conditions must be met.
- Such use must be accomplished in accordance with an appropriate medical rationale; and
- If scientific information on the human food safety aspect of the use of the drug in food-producing animals is not available, the veterinarian must take appropriate measures to assure that the animal and its food products will not enter the human food supply.
- Extralabel use of an approved human drug in a food-producing animal is not permitted under 21 CFR 530.20 if an animal drug approved for use in food-producing animals can be used in an extralabel manner for the particular use.
Non-food animals & ELDU
- Because ELDU of animal and human drugs in nonfood-producing animals does not ordinarily pose a threat to the public health, extralabel use of animal and human drugs is permitted in nonfood-producing animals except when the public health is threatened.
- ELDU is permitted if there is no approved animal drug labeled for the use and containing the same active ingredient in the required dosage form and concentration, except where a veterinarian finds, within the context of a valid VCPR that the approved drug is clinically ineffective for its intended use.
- If FDA determines that an ELDU in animals not intended for human consumption presents a risk to the public health, the agency may publish in the Federal Register a notice prohibiting such use. The prohibited ELDU will be codified in 21 CFR 530.41, which is the same place FDA lists the drugs that are prohibited for ELDU for food-producing animals.