Article

Introduction

In this second of three articles, we will look at how veterinary drugs can be better managed in small animal practice, such that resistance and environmental contamination are minimized. These discussions are often limited by a lack of evidence, but there are sensible precautions that can be taken in the absence of appropriate data. The final article will suggest, amongst other things, what evidence may need to be gathered in the future to safeguard the efficacy of these drugs whilst also protecting the environment. 

This article will consider three groups of drugs, namely antibacterials, parasiticides and chemotherapeutics. Whilst fungicides and antiviral agents are also considered antimicrobials – and much of our understanding of what constitutes responsible antibacterial prescribing can probably be applied to other categories of antimicrobials – the evidence base is less in these latter classes (1). 

Guidelines for responsible antibacterial use

A coordinated and rigorously implemented One Health approach to antibacterial stewardship is vital to preserve the effectiveness of currently available antibacterials for future generations. Multiple independent initiatives have been developed that offer recommendations for rational antibacterial use in small animals, including the BSAVA PROTECT ME guidelines, the Danish Antibiotics Use Guidelines, CEVA’s GRAM book and other national resources (Box 1) (2).

Box 1. The European Medicines Agency antibiotic categories.

Further organ-system-specific guidance on antibacterial use has been produced by the International Society for Companion Animal Infectious Diseases (ISCAID) covering urinary tract infections, respiratory disease and pyoderma management (3-5). More recently, European guidelines have been developed to support the management of canine acute diarrhea (6) and decision making for surgical prophylaxis in companion animals (7). There are also a range of online educational platforms that help clinicians access and implement stewardship measures (8). An impressively consistent message has been documented across these resources, especially around “big win” conditions: i.e., commonly encountered clinical situations that can be effectively and safely managed without antibiotics.

Awareness of antibacterial use guidelines correlates strongly with an increased tendency to withhold antibacterials for conditions that typically improve without their use (e.g., feline lower urinary tract disease, acute vomiting or acute diarrhea, and upper respiratory tract infections) (9). Familiarity with all these antimicrobial use guidelines is increasing – the hope now is that this will translate into high levels of adherence and improved stewardship. Already the reported reduction in the length of a typical antibacterial course for sporadic canine cystitis from a median of 14 days in 2016/17 to 10 days in 2018 could reflect greater awareness of ISCAID recommendations (10).

It is critical that the recommendations are effectively communicated to the target audience to successfully influence prescriber habits. This may be facilitated through using new technologies (e.g., the First Line app produced by the Ontario Veterinary college (11) offers veterinary stewardship guidance) or by translating materials into different languages to improve accessibility (9). 

Rational antibacterial prescribing

There are many resources that offer excellent advice, however for the purposes of this article the authors will use the acronym PROTECT ME to illustrate the basic principles of good antibacterial stewardship (Figure 1) (Box 2). The PROTECT ME poster (first developed in 2012 and updated twice since, in 2019 and 2023) was developed to generate discussion at practice meetings so that all guideline users have a personal stake in their practice’s stewardship approach. It has become a key resource for veterinarians in practice in the UK and beyond, and it is recommended that all practices should review their use of antibiotics in line with the principles it identifies.

Figure 1. The PROTECT ME acronym offers succinct guidance to help improve knowledge and understanding of antibacterial resistance in veterinary professionals and owners; this is vital to reduce the threat from resistant strains of bacteria. 

Box 2. Ensuring good antibiotic stewardship in practice (adapted from 12).

• Prescribe antibacterials only when necessary. Unnecessary antibacterial use in small animals is common. They are often prescribed for conditions that have no bacterial cause, such as diarrhea, cough, nasal discharge and feline cystitis. Many of these presentations have viral, toxic, or immune-mediated origins, making antibacterials ineffective and potentially delaying appropriate treatment. Even with secondary bacterial infections, addressing the root cause may eliminate the need for antibacterials. In surgery, antibacterials should not replace proper asepsis, and clean operations (e.g., neutering, dermal mass removals) do not require antibacterials. It is important to question the routine use of post-operative antibacterials and consider if they truly impact surgical outcomes; post-operative antibacterial use is nowadays even being abandoned in orthopedic surgeries involving implants. 
• Replace with non-antibacterial treatments. Non-antibacterial approaches should be considered “first choice” in more cases (Figure 2). For instance, acute hemorrhagic diarrhea syndrome is increasingly treated with intravenous fluids, good nursing, anti-emetics and probiotics, but without antibacterials. Cat bite abscesses can often be managed with lancing, drainage and lavage alone. Canine kennel cough can often be managed with cough suppressants and rest. 
• Optimize doses and routes of use. Shorter antibacterial courses are often as effective as longer ones. Human medicine has moved away from arbitrary durations, and veterinary practice should follow suit. The “Stop on Sunday” trial is investigating optimal durations for sporadic canine cystitis (13). Practices can trial shorter courses with reassessment before completion. Topical treatments should be preferred where possible to reduce systemic antibacterial impact on microbiomes.
• Treat effectively. Clinicians should always consider which bacteria are likely to be involved in a particular case when prescribing. It is also important to think which antibacterials will penetrate the affected tissues. As this information is not always available, clinicians can use guidelines (such as the PROTECT ME poster) to help them select effective drugs for specific infections. Conditions such as pyelonephritis and prostatitis require antibacterials that reach these sites, e.g., fluoroquinolones or potentiated sulfonamides. Proper administration is also key – resources like the International Cat Care website (14) offer guidance to owners on how to give oral medications correctly, potentially reducing reliance on long-acting injections. 
• Employ narrow spectrum antibiotics. Broad-spectrum antibacterials encourage resistance, whereas narrow-spectrum choices limit the effects on commensal bacteria and preserve future treatment options. In severe infections requiring immediate treatment, broad-spectrum antibacterials may be necessary initially, but culture results should guide refinement. Culturing justifies costs by enabling targeted treatment, often with cheaper antibacterials, and reduces multi-drug resistance risks.
• Conduct cytology and culture. Cytology and bacterial culture are essential for antibacterial stewardship; cytology quickly confirms bacterial involvement, while culture identifies resistance patterns. This is particularly critical for prolonged treatments, resistant infections, and life-threatening cases. First-line treatment failures should not lead to changes in antibacterial without culture results; “if at first you don’t succeed, try a different approach rather than a different drug.”
• Tailor the practice policy. A collaborative, evidence-based antibacterial policy in the clinic ensures responsible prescribing. Completing PROTECT ME posters helps establish first-line approaches. Policies should cover antibacterial choices, diagnostic tests and alternative treatments. The importance of stakeholder engagement to maximize the impact of antibacterial use guidelines has been recognized in both human and veterinary healthcare settings (15,16). 
• Monitor the local situation and performance. Track surgical site infections and adjust protocols as needed. Audit antibacterial use, particularly restricted antibacterials like fluoroquinolones and cefovecin.
• Educate and collaborate. Client pressure for antibacterials often stems from lack of awareness; explaining alternatives and risks reduces this pressure, and educating pet owners on hygiene and disease prevention supports responsible prescribing. Tools such as non-prescription forms can reinforce decisions not to prescribe antibacterials, a proven strategy in human medicine.

By implementing these practices, we can reduce unnecessary antibacterial use, improve treatment outcomes, and mitigate the rise of antibacterial resistance.

Rational parasiticide prescribing 

In contrast to the situation with antibacterial resistance, the principles of responsible parasiticide prescribing are less clearly defined and rely far more on local knowledge and understanding of risk. There has been a cultural shift in many countries over the last three decades from using parasiticides as treatments of confirmed infestations to routine preventative health care. This shift has occurred in response to the development of safer (to the animal), more convenient treatments and the spread of parasites such as Angiostrongylus that cause significant disease in pet populations (17). 

Clinicians should always take a risk-based approach to prescribing parasiticides, rather than simply using them routinely. In certain areas of some countries, the risks and hazards of parasites (e.g., the canine heartworm (Dirofilaria immitis)) are such that routine prophylaxis is required (18). However, this cannot be extended to all parasites in all countries. Even in those areas that do have recommendations for routine prophylaxis, it is important to use the narrowest spectrum products and use them properly. It is accepted that there are many gaps in evidence base in relation to parasites and parasiticides, which makes risk analysis difficult. The authors propose that clinicians and owners consider the “IMPACT” of parasiticides before they use them by doing the following listed in Table 1.

Table 1. How to estimate the IMPACT of parasiticides before they are used.

Veterinarians should ensure they have their client’s informed agreement and the support of well-established guidelines and/or practice protocols when prescribing parasiticides. In the UK this approach is based on the advice within the BVA, BSAVA and BVZS policy position on responsible use of parasiticides for cats and dogs (19) and sits alongside existing resources such as the 5-point plan poster (Figure 3). In other countries, there are national legal requirements, guidelines and policies that should be consulted and carefully considered. 

Testing for endoparasites may help to reduce unnecessary use of endoparasiticides, assess local and individual risk levels, and detect potential parasiticide resistance. However it is important to realize that different fecal flotation techniques can give different results, depending on the parasite and the method (20). Collated data from different laboratories can give an assessment of regional or national prevalence, but this may not be applicable locally (21). 

Good chemotherapeutic prescribing 

The use of chemotherapy agents in small animal practice is an occupational, animal and public health hazard (22). The use of these agents is rising, and they are being used in a wider range of practice settings. Developments in chemotherapy (such as metronomic therapy) may further reduce practice control, as clients will administer the drugs at home. Additionally, novel agents like small molecular c-kit inhibitors, though not conventional chemotherapy, may pose similar risks, especially during pregnancy, and should be handled as cytotoxic drugs. Some basic rules apply:

• The right indication: As there are considerable risks associated with chemotherapy exposure, both to the patient and those involved in handling the chemotherapeutics, these agents should only be prescribed when absolutely indicated. This indication requires the disease to be confirmed histologically or cytologically and that the disease is likely to respond. Investigational use should be confined to controlled clinical trials.
• Reducing exposure: Occupational exposure can occur during the handling of the agents, either from cleaning spills, or through contact with bodily fluids or excreta of patients treated with chemotherapy. Exposure may occur via direct skin contact, inhalation of aerosolized drug particles, ingestion, or needle stick injuries. The environment in which the patient is treated and housed after chemotherapy is at risk of contamination from feces, urine and other bodily fluids, therefore owners and the environment are all at risk of contamination (23). 
• Clinicians should assess the suitability of the environment and staffing (both level and training) for chemotherapy administration before attempting it, and should also assess an owner’s abilities to adhere to the protocols for waste management. All owners should be given written information about the potential hazards of cytotoxic drugs (to humans, treated pets and the environment). This should include the excretion period relevant to the drug(s) administered, and how to deal with the patient’s excreta (i.e., saliva, urine, vomit, feces). 
• Cost and chemotherapy safety: Undoubtedly some of the mitigating measures described above will increase the cost of chemotherapy and, unfortunately in some cases, may make treatment unaffordable. However, practices have legal responsibilities to safeguard their employees and the public, and veterinary professionals have a duty of care to their patients. Therefore, cost is not a reason for not following suitable safety procedures. For more information on specific handling protocols for chemotherapeutics, various resources are recommended (24). 

Conclusion

Inevitably in prescribing and using medicines to treat animal disease, veterinarians encounter dilemmas in balancing human, animal and environmental health whilst achieving the best outcome for their patients. Guidelines are useful points of reference, but are only of real value if they are independent, evidence-based, and followed by most of the profession. In the next article we will look at those factors that need to be in place for the development of robust guidelines and for veterinarians and owners to follow best practice. 

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