Neglected but Not Harmless: Characterising Nonantibiotic Antimicrobial Use in Small Animal Practices in Colombia

BACKGROUND: Antimicrobial resistance (AMR) is a growing global threat, yet stewardship efforts have largely overlooked nonantibiotic antimicrobials (NAAs), despite their widespread use and potential role in resistance selection and environmental persistence. Evidence on NAA use in small animal practice, particularly in low- and middle-income countries, remains scarce. OBJECTIVE: To characterise patterns of NAA use and assess prescription quality in dogs, cats, and other small animal species treated at a university veterinary hospital in Colombia. METHODS: A retrospective cross-sectional study was conducted using veterinary prescription records from January to December 2022. A systematic sampling approach (first four prescriptions per day) yielded 1460 prescriptions, of which 731 involved NAAs. Data on animal characteristics, consultation type, and prescription details were extracted, and NAAs were classified by pharmacological group, pharmaceutical form, and route of administration. Bivariate analyses were performed to identify stewardship-relevant patterns. RESULTS: NAAs accounted for a substantial proportion of prescriptions, predominantly in dogs (91.5%). Topical antiseptics (49.9%), external antiparasitics (21.3%), and internal antiparasitics (17.1%) were the most frequently used classes. Cutaneous (58.7%) and oral (41.3%) routes predominated, with chlorhexidine as the most common active ingredient (22%). Dermatology consultations were more likely to involve topical antiseptics (55.0% vs. 45.5%; OR = 1.47; 95% CI 1.06-2.02), whereas general consultations showed substantially higher odds of internal antiparasitic use (OR = 5.58; 95% CI 2.93-10.62). While 67.6% of treatments adhered to standard duration, only 38% matched recommended dosing, and key prescription elements were frequently missing, including International Nonproprietary Names (7%), concentration (12.2%), and complete administration instructions (5.5%). CONCLUSIONS: NAAs are widely used in small animal practice but are frequently prescribed with incomplete documentation and suboptimal dosing practices. These findings highlight a critical and underrecognised gap in antimicrobial stewardship and support the need to formally integrate NAAs into surveillance, regulatory frameworks, and stewardship interventions under a One Health approach.