Technical Advice: Authorisation of Critically Important Antibiotics for future use

4 August 2022

Technical advice is our interpretation of how professional standards apply in a particular situation. It is designed to help veterinarians deal with common issues in practice, using their professional judgement to apply the advice to their own situation. It represents our best efforts at the time of publication but standards and expectations change over time and particular care should be used when reading old advice.


In what circumstances is it appropriate to authorise (prescribe) critically important antibiotics for a client to hold for future use


Antimicrobial resistance (AMR) is a recognised global issue and one of the World Health Organisation’s top ten global public health threats. The veterinary profession is responsible for authorising antimicrobials and therefore is obliged to manage the associated risks.

Critically Important Antibiotics (CIAs) are antibiotics that are considered critically important to human health and animal health as identified by the World Organisation for Animal Health and the World Health Organization.

Image courtesy of the NZVA. CIAs are classified as Red in this traffic light system.

The prudent use of all antimicrobials, including CIAs is a crucial aspect of managing the risks and slowing development of AMR.

As well as the human, animal and environmental health risks, antimicrobial use has implications for international trade and continued market access.

While the choice of antimicrobial agent is important to the success of treatments, the reasons for treatment failure are often multifactorial and are not necessarily directly related to the antimicrobial chosen.

Authorisation of CIAs

Veterinarians can authorise Restricted Veterinary Medicines (RVMs) for a specified person to hold specific RVMs in anticipation of use (See the ACVM Notice: Requirements for Authorising Veterinarians). This, in effect, allows for clients (farmers, most commonly) to determine when to treat an animal, which RVM to select (including antimicrobials), and when treatment has succeeded or failed, based on the instructions provided by the authorising veterinarian.

The Code allows for veterinarians to provide an authorisation of CIAs for a period of supply of up to 4 months. The Code also provides explicit actions veterinarians must take to ensure they are authorising CIAs correctly (see the Veterinary Medicines chapter, Section 6):

Actions veterinarians must take to ensure they use Critically Important Antibiotics correctly

  1. Restrict use to situations where first line antibiotics have been shown to be ineffective.
  2. Restrict use to cases supported by bacteriological tests or where the prescribing [authorising] decision is supported by studies or references that are recent and independently peer reviewed.
  3. Do not use critically important antibiotics as preventive treatment in animal feed or water in the absence of clinical signs in the animal to be treated.
  4. Limit off label use for instances where no suitable alternatives are available.

Specifically points 12 and 13 above specify expectations to be met prior to the use of CIAs.

We interpret “have been shown to be ineffective” as being:

  • Where there is sufficient evidence (supported by studies or references that are recent and independently peer reviewed) that the organism to be treated is not susceptible to first line (i.e green / orange) antibiotics.
  • Where there has been an appropriate veterinary investigation which includes:
    • review of the relevant preventative control programme;
    • assessment of the competence of relevant personnel to identify disease and administer appropriate treatment;
    • whether an acceptable treatment protocol has been implemented and complied with; and
    • whether there is any evidence of therapy failure or relapse that supports the use of a CIA.

Authorisation for future use

We take the above requirements to mean that there are very few situations where it would be considered permissible for CIAs to be left on farm for future use.

These are for example, where:

  1. A course of treatment with a CIA has been appropriately authorised by a veterinarian, following a consultation, for:
  • a specific animal/s with a diagnosed condition.
  • a group of animals in the face of a diagnosed outbreak
  1. A veterinarian authorises a CIA product as part of a herd health programme because:
  • The client has on-farm diagnostic equipment that is used to identify the causative bacteria and there are sensitivity testing results that indicate the CIA product is most appropriate to use (e.g. multiple prior culture results from the herd, or sensitivity results from the on-farm testing equipment) prior to the administration of the CIA; and
  • The authorising veterinarian undertakes regular and appropriately frequent visits (For example – no less frequent than the CIA period of supply); and
  • The authorising veterinarian has confirmed all personnel responsible for administering the CIA have been provided the appropriate level of advice and training and are competent to carry out all instructions given within the authorisation.
  1. A specific disease condition has been diagnosed on the property and it has been established using legitimate and sound clinical rationale which is evidence based (supported by diagnostic testing, studies or references that are recent and independently peer reviewed) that the use of a CIA is the appropriate first-choice treatment.

In all circumstances where veterinarians authorise CIAs, they remain responsible for the subsequent use of these products and must:

  • Substantiate and record their decision-making process to establish that use of the CIA is justified; and
  • Have appropriate record keeping of the diagnostics and CIAs administered; and
  • Conduct and record a regular audit and reconciliation of the CIAs authorised within the term of the period of supply.

Disposal of expired or unused CIAs, needles and syringes

CIAs are considered hazardous wastes and are a threat to public health, safety and the environment.

In clinic waste or waste generated by veterinarians on farm must be disposed of into appropriate containers which meet the relevant Australian and/or New Zealand standards for reusable and non-reusable containers e.g. approved sharps containers, hazardous waste containers, and appropriate biohazard containers for general waste.

Veterinarians must also advise clients on how to:

  • return needles, syringes and empty containers to the clinic, and
  • return unused or expired products to the clinic, or
  • Appropriately dispose of this hazardous waste.