A New England veterinarian who prescribed and dispensed gentamicin for treatment of a cow's mastitis recently received a warning letter from the FDA.
An illegal residue of gentamicin was detected in the cow when it was offered for sale and slaughter for human food, according to the May/June issue of the FDA Veterinarian.
Gentamicin is not approved for use in cattle, and there is no established tolerance for residues in the edible tissues of cattle.
Under AMDUCA, veterinarians may legally use aminoglycosides in cattle, but as with any extralabel drug use, food safety must be ensured, and a violative food residue or any residue that may present a risk to public health is not permitted.
The Food Animal Residue Avoidance Databank (FARAD) recommends a withdrawal time of up to 18 months when gentamicin is injected into cattle.
Organized veterinary medicine has, however, called on veterinarians to avoid the extralabel use of aminoglycosides in cattle because of the propensity for drugs of this class to be retained in kidney tissue for long periods.
The AVMA House of Delegates approved its position statement in 1998: that until further scientific information becomes available, aminoglycoside antimicrobials should not be used in cattle, except as specifically approved by the FDA.
Similarly, the AABP encourages its members to refrain from the intramuscular, subcutaneous, or intravenous extralabel use of the aminoglycoside class of antimicrobials "in bovines."