The Food and Drug Administration (FDA) oversees the licensing of pharmaceuticals for humans and animals. Many drugs that have been approved for use in humans and/or some animals have also been proven to be safe and effective in other species for which the drugs are not labeled. When drugs are FDA-approved for use in one species but is given to another species that has not been approved and labeled for, the terminology is that the drugs are being used in an “extra-label” manner.
Extra-label use does not include the use of experimental drugs or drugs manufactured in foreign countries that have not been approved by the FDA. Despite this lack of FDA approval, it may be necessary to occasionally use such drugs when no other effective options exist.
Because few drugs are labeled for use in small animals, most drugs administered by veterinarians, including antibiotics, anesthetics, and other medications, are routinely used in an extra-label manner. This is within the standard of care, but good medical practice requires that owners be advised when drugs are being used in an extra-label manner.
All drugs can potentially cause harmful side effects, including death. The drugs that will be used for your pet have been safely used in individuals of the same or related species. When a drug must be used to treat an unusual disease, effectiveness and safety can be difficult to predict. You will be advised when your pet has been prescribed a medication that has not been given to a significant number of individuals of a similar species with a similar medical condition. You will be advised if an effective FDA-approved drug is not available and it becomes necessary to use a drug that has not been approved by the FDA to treat your pet.