FDA’s Warning Letters were directed at firms manufacturing and distributing OTC animal drugs for use in aquarium fish and birds. The OTC drugs in question were not approved by FDA, nor listed on FDA's index for unapproved animal drugs for minor species. Importantly, FDA stated in all nine Warning Letters that the agency was “particularly concerned” about the public health risks of these unapproved products, given that they were sold without veterinary prescriptions while containing antimicrobials that were medically important in the treatment of human disease. The antimicrobials found in these drugs identified in the Warning Letters included[1]:

• Amoxicillin
• Azithromycin
• Cephalexin
• Ciprofloxacin
• Clindamycin
• Doxycycline
• Erythromycin
• Levofloxacin
• Metronidazole
• Minocycline
• Neomycin
• Penicillin
• Trimethoprim/Sulfamethoxazole

Each of these antimicrobials has been previously identified by FDA in draft guidance as a “medically important antimicrobial,” meaning these antimicrobials are important for treating human disease. For more than a decade, CVM has undertaken efforts to support the judicious use of antimicrobials in animals, with the aim of slowing antimicrobial resistance in humans by optimizing therapeutic efficacy and minimizing selection of resistant microorganisms. Notably, CVM announced a 5-year action plan in 2018 supporting antimicrobial stewardship in veterinary settings. This has resulted in some significant initiatives, such as CVM encouraging sponsors to voluntarily change their FDA-approved OTC animal drugs containing medically important antimicrobials to prescription status. The Warning Letters represent FDA’s effort to extend this initiative to unapproved drugs containing antimicrobials important for human health that are sold without veterinarian prescription oversight.