Compounding of animal drugs In general, compounding an animal drug from an active pharmaceutical ingredient (bulk drug) is not permitted by the act unless covered by an approved new animal drug application. This is true even if the compounder is a veterinarian or a pharmacist. However, CVM acknowledges the medical need for compounding may exist within certain areas of veterinary practice. The contemporary practice of veterinary medicine requires products to treat hundreds of conditions and diseases in dozens of species. Business and market realities in the animal health industry can only provide a fraction of products necessary for these indications. Consequently, veterinarians continue to require products to treat diseases or conditions in animals for which no FDA-approved product is available. Veterinarians must by necessity on occasion utilize products that are compounded to meet a specific patient’s medical need. Extra-label use of FDA-approved drugs in animals “Extra-label use” is defined as: Actual use or intended use of a drug in an animal in a manner that is not in accordance with the approved labeling. This includes, but is not limited to, use in species not listed in the labeling, use for indications (disease and other conditions) not listed in the labeling, use at dosage levels, frequencies, or routes of administration other than those stated in the labeling, and deviation from labeled withdrawal time based on these different uses. Under the provisions of the Animal Medicinal Drug Use Clarification Act of 1994, the FDA allows the extra-label use of drugs by veterinarians when the health of an animal is threatened or suffering or death may result from failure to treat. Any drug used in an extra-label manner is by definition a prescription drug, since the involvement of a veterinarian is required, and it may only be prescribed within the scope of a valid VCPR. Labeling of drugs prescribed for extra-label use At a minimum, the following label information is recommended: 1. The name and address of the prescribing veterinarian. 2. The established name of the active ingredient(s). 3. Directions for use specified by the practitioner (including animal identification; dosage, frequency, and route of administration; and duration of therapy). 4. Cautionary statements specified by the veterinarian. 5. Veterinarian’s specified withdrawal/discard time(s) for meat, milk, eggs, or any food that might be derived from the treated animals. Because extra-label use of animal and human drugs in nonfood-producing animals (companion, sporting, exotic, etc.) does not ordinarily pose a threat to the public health, extra-label use of animal and human drugs is permitted in these species within the context of a VCPR, except where the public health is threatened. Limitations to extra-label use provisions of AMDUCA The following specific extra-label uses are prohibited: 1. Extra-label use in an animal of an approved animal or human drug by a lay person (except under the supervision of a licensed veterinarian). 2. Extra-label use of an approved new animal drug or human drug in or on an animal feed.
Recently, the CVM issued new guidance (GFI #256) on compounding veterinary drugs from bulk substances. The primary impact of this guidance, as it will be experienced by most veterinary practices, is to limit which drugs can be compounded and stocked by veterinary hospitals for clinical use. Veterinarians working with companion animals can only maintain compounded drugs from the List of Bulk Drug Substances for Compounding Office Stock Drugs for Use in Nonfood-Producing Animals in stock for use in their patients.10 In most cases, compounded drugs can still be ordered from a compounding pharmacy for an individual patient when there is a documented medical need. However, stocking compounded drugs for dispensing to a variety of patients (for example, compounded ear medications to be prescribed on an as-needed basis) will no longer be permissible in many cases. For more information on GFI #256, see the FDA CVM’s Frequently Asked Questions website. 11 Extra-label use of drugs may be considered by food animal veterinarians only when there is no approved new animal drug containing the same active ingredient in the required dosage form and concentration (unless the approved drug has been found to be clinically ineffective). The veterinarian must also make an informed diagnosis, establish an appropriate withdrawal time to avoid illegal drug residues (or keep the animal out of the food supply if no scientific information exists), and institute procedures to assure that the identity of the treated animal(s) is/are carefully maintained. Extra-label medication use in food animals must always be supported by an appropriate medical rationale and cannot be used to enhance production. The prescribed or dispensed extra-label drug (prescription legend or over-the-counter) must bear labeling information that is adequate to ensure the safe and proper use of the product. 3. Extra-label use resulting in any residue that may present a risk to the public health. 4. Extra-label use resulting in any residue above an established safe level, safe concentration, or tolerance. FDA may also prohibit the extra-label use of an approved new animal or human drug or class of drugs in animals if FDA determines that: 1. An acceptable analytical method has not been established or cannot be established. 2. The extra-label use of the drug or class of drugs presents a risk to the public health. A prohibition on a drug or drug class may be a general ban or may be limited to a specific species, indication, dosage form, route of administration, or combination of factors. The following drugs are prohibited for extra-label use in all animals: 1. Chloramphenicol 2. Clenbuterol 3. Diethylstilbestrol (DES)
4. Dimetridazole 5. Ipronidazole 6. Other nitroimidazoles
7. Furazolidone 8. Nitrofurazone
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