Judicious Therapeutic Use of Antimicrobials in Cats and Dogs

Judicious use of antimicrobials in animals requires the oversight of a veterinarian.

• Judicious use of antimicrobials and extralabel use of antimicrobials should meet all requirements of a valid veterinarian-client-patient relationship (VCPR—see glossary).

Preventive strategies, such as appropriate husbandry and hygiene, routine health monitoring, and vaccinations, should be emphasized.

Routine preventive healthcare in cats and dogs includes the following:

• Adherence to the AAHA/AAFP’s guidelines for feline vaccinations and AAHA’s guidelines for canine vaccinations.
• Parasite control, nutritional counseling, and dental health care.
• Client education and involvement to successfully adopt good preventive health care programs.
• Appropriate hygiene and husbandry is especially important in multiple pet households.

The routine prophylactic use of antimicrobials should never be used as a substitute for good animal health management.

• The use of antimicrobials to prevent infection (e.g., prophylaxis)⁴ can only be justified in cases where bacterial infection is likely to occur or where the implications of infection are particularly high (e.g., central nervous system surgery).

Therapeutic alternatives should be considered before, or in conjunction with, antimicrobial therapy.

• This includes supportive care, such as correction of fluid and electrolyte abnormalities, maintaining acid-base balance, and ensuring adequate nutrition.
• Surgical intervention may be necessary in some cases, such as abscessation, empyema, or other diseases requiring source control.
• Consider supportive care, including dietary therapy and probiotics for acute, nonfebrile diarrhea.^5,12,13
• Consider antiseptic preparations and topical (e.g., skin) or locally applied antimicrobials (e.g., oral cavity) as alternatives to systemic antimicrobials.^6,7

Considerations should be made whether to delay or alter antimicrobial therapy based on patient status.

• Use delayed prescribing or watchful waiting if a patient’s disease might not be caused by a bacterial infection or in certain situations in which patients are expected to clear an infection on their own.
• Reassess the need for and choice of antimicrobial drugs throughout the course of therapy (antimicrobial “time out”).^2,8

Antimicrobials considered important in treating refractory infections in human or veterinary medicine should be used in animals only after careful review and reasonable justification.

• Consider using other antimicrobials for initial therapy.
• Drug side effects or interactions should be considered when choosing an appropriate antimicrobial.
• Ensure any use of antimicrobials considered important in treating refractory infections is supported by the lack of another antimicrobial option, the presence of cytology, culture and susceptibility testing, and a reasonable chance for a cure. Consultation with an expert in infectious disease and antimicrobial therapy should be undertaken when appropriate and available.^7,15–19

Regimens for therapeutic antimicrobial use should be optimized using current pharmacological information and principles.

• The antimicrobial chosen should be effective against the organism and be able to penetrate the affected body site in an adequate concentration to eliminate the offending organism.
• Consider the intrinsic resistance of pathogens to antimicrobials.^20,21
• Consider patient- and site-specific factors that may limit response to antimicrobial therapy (e.g., protected body site and local tissue factors).¹⁹
• Consider patient factors that may influence drug metabolism (e.g., renal or hepatic disease) or concurrent medications that may affect drug levels.
• For information on dose, route, frequency, and duration of administration, refer to label indications, laboratory standards, and current guidelines from veterinary professional organizations.
• Risks to patients from antimicrobials should be considered and discussed with owners before use (e.g., enrofloxacin-induced retinotoxicity and aminoglycoside-induced nephrotoxicity).

Duration of therapy should be based on scientific and clinical evidence in order to obtain the desired health outcome while minimizing selection for antimicrobial resistance.

• For specific conditions, refer to appropriate resources and consensus guidelines.^7,15,16

Antimicrobial therapy must be prescribed in accordance with all local, state, and federal laws (e.g., extralabel usage in the United States).

Accurate records of treatment, outcome, and indication for use should be maintained to evaluate therapeutic regimens.

Veterinarians should work with animal owners and caretakers to ensure the judicious use of antimicrobials.

• Administration instructions for antimicrobials must be made clear and labeled correctly (e.g., doxycycline capsules or tablets must be followed by a liquid to avoid esophageal stricture).
• Clients should be advised to administer medications as directed by their veterinarian, including medication timing and duration of use.
• As with all medications, proper client instruction in administration techniques is crucial to ensure compliance and safety of the pet and the owner.
• Clients should be warned of potential adverse reactions and instructed on what to do if any such reactions occur (e.g., stop medication and call your veterinarian for further recommendations).
• Animal owners should consult with their veterinarian before any antibiotic use, even for antibiotics available without a prescription, to ensure positive outcomes and prevent complications.

Minimize environmental contamination with antimicrobials whenever possible.^22,23

• Minimize environmental contamination with antimicrobials by following local, state, and federal guidelines for disposal.²⁴