Judicious Therapeutic Use of Antimicrobials

Comment on this policy


Position Statement

When the decision is reached to use antimicrobials for therapy, veterinarians should strive to optimize therapeutic efficacy and minimize resistance to antimicrobials to protect public and animal health.




  • Support development of a scientific knowledge base that provides the basis for judicious therapeutic antimicrobial use.
  • Support educational efforts that promote judicious therapeutic antimicrobial use.
  • Preserve therapeutic efficacy of antimicrobials.
  • Ensure current and future availability of veterinary antimicrobials.




  • Facilitate development and distribution of appropriate antimicrobial use guidelines by practitioner species-interest groups.
  • Improve scientifically based therapeutic practices through education.


Recognized Needs


  • Improved monitoring and feedback systems for antimicrobial use and resistance patterns.
  • Research to improve scientifically based therapeutic practices.


Judicious Use Principles


  • Preventive strategies, such as appropriate husbandry and hygiene, routine health monitoring, and immunization, should be emphasized.
  • Other therapeutic options should be considered prior to antimicrobial therapy.
  • Judicious use of antimicrobials, when under the direction of a veterinarian, should meet all requirements of a veterinarian-client-patient relationship.
  • Prescription, Veterinary Feed Directive, and extralabel use of antimicrobials must meet all the requirements of a veterinarian-client-patient relationship.
  • Extralabel antimicrobial therapy must be prescribed only in accordance with the Animal Medicinal Drug Use Clarification Act amendments to the Food, Drug, and Cosmetic Act and its regulations.
  • Veterinarians should work with those responsible for the care of animals to use antimicrobials judiciously regardless of the distribution system through which the antimicrobial was obtained.
  • Regimens for therapeutic antimicrobial use should be optimized using current pharmacological information and principles.
  • 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.1
  • Use narrow spectrum antimicrobials whenever appropriate.
  • Utilize culture and susceptibility results to aid in the selection of antimicrobials when clinically relevant.
  • Therapeutic antimicrobial use should be confined to appropriate clinical indications. Inappropriate uses such as for uncomplicated viral infections should be avoided.
  • Therapeutic exposure to antimicrobials should be minimized by treating only for as long as needed for the desired clinical response.
  • Limit therapeutic antimicrobial treatment to ill or at risk animals, treating the fewest animals indicated.
  • Minimize environmental contamination with antimicrobials whenever possible.
  • Accurate records of treatment and outcome should be used to evaluate therapeutic regimens.

1In this context, this principle takes into account development of resistance or cross-resistance to important antimicrobials.



*These terms are to be defined and utilized in the context of Judicious Therapeutic Use, with the intent of focusing on antimicrobials that may be of significance to human health. They are to be applied to the principles of Judicious Use outlined within the context of this document.


Antibiotic--a chemical substance produced by a microorganism which has the capacity, in dilute solutions, to inhibit the growth of or to kill other microorganisms.

Antimicrobial--an agent that kills microorganisms or suppresses their multiplication or growth.

Broad Spectrum Antimicrobial--a type of antimicrobial effective against a large number of bacterial genera; generally describes antimicrobials effective against both Gram-positive and Gram-negative bacteria.

Narrow Spectrum Antimicrobial--a type of antimicrobial effective against a limited number of bacterial genera; often applied to an antimicrobial active against specific families of bacteria.

Antimicrobial Resistance--a property of microorganisms that confers the ability to inactivate or elude antimicrobials or a mechanism that blocks the inhibitory or killing effects of antimicrobials.

Extralabel Use--extralabel use means actual use or intended use of a drug under veterinary direction, 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 or 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 the labeled withdrawal time based on these different uses.

Immunization--the process of rendering a subject immune or of becoming immune, either by conventional vaccination or exposure.

Monitoring--monitoring includes periodic health surveillance of the population or individual animal examination.

Therapeutic--treatment, control, and prevention of disease.

Veterinarian/Client/Patient Relationship (VCPR) -- A VCPR exists when all of the following conditions have been met:

  1. The veterinarian has assumed the responsibility for making clinical judgments regarding the health of the animal(s) and the need for medical treatment, and the client has agreed to follow the veterinarian's instructions.
  2. The veterinarian has sufficient knowledge of the animal(s) to initiate at least a general or preliminary diagnosis of the medical condition of the animal(s). This means that the veterinarian has recently seen and is personally acquainted with the keeping and care of the animal(s) by virtue of an examination of the animal(s) or by medically appropriate and timely visits to the premises where the animal(s) are kept.
  3. The veterinarian is readily available for follow-up evaluation, or has arranged for emergency coverage, in the event of adverse reactions or failure of the treatment regimen.

Veterinary Feed Directive (VFD) Drug--The VFD category of medicated feeds was created by the Animal Drug Availability Act of 1996 to provide an alternative to prescription status for certain therapeutic animal pharmaceuticals for use in feed. Any animal feed bearing or containing a VFD drug shall be fed to animals only by or upon a lawful VFD issued by a licensed veterinarian in the course of the veterinarian's professional practice.

Relevant AVMA Policy: