Off-Label Use of Human Over-the-Counter (OTC) Products in Veterinary Medicine: A Literature Review on Effects, Risks, and Safety Precautions

Ida Fitriana; Antasiswa Windraningtyas Rosetyadewi; Ika Nindya Irianti; Agustina Dwi Wijayanti

doi:10.22146/ijvs.v4i2.106709

Off-Label Use of Human Over-the-Counter (OTC) Products in Veterinary Medicine: A Literature Review on Effects, Risks, and Safety Precautions

https://doi.org/10.22146/ijvs.v4i2.106709

Ida Fitriana^(1*), Antasiswa Windraningtyas Rosetyadewi⁽²⁾, Ika Nindya Irianti⁽³⁾, Agustina Dwi Wijayanti⁽⁴⁾

(1) Department of Pharmacology, Faculty of Veterinary Medicine, Universitas Gadjah Mada
(2)
(3)
(4)
(*) Corresponding Author

Abstract

The off-label use of human over-the-counter (OTC) medications in veterinary medicine is a common but potentially hazardous practice, particularly in regions where access to veterinary-approved drugs is limited. While some OTC agents, such as diphenhydramine or melatonin, may offer therapeutic benefits under veterinary supervision, many others pose significant risks due to species-specific differences in drug metabolism, narrow safety margins, and the presence of toxic excipients such as xylitol, pseudoephedrine, or acetaminophen. This literature review examines the rationale behind such practices, the most commonly used OTC drug classes, and the associated pharmacological and toxicological risks. It also highlights critical considerations in clinical decision-making, including appropriate dosing, contraindications, and alternative treatment options. Additionally, the role of veterinary pharmacists, interprofessional collaboration, and pharmacovigilance systems are discussed as essential components in mitigating risks and promoting safe usage. The review emphasizes the importance of client education and the need for veterinarians to rely on species-specific products whenever available. Ultimately, the off-label use of OTC medications in animals should be approached with caution, guided by evidence-based practice, and employed only when clinically justified and accompanied by rigorous safety monitoring.

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References

Allen, A. L. (2003). "The diagnosis of acetaminophen toxicosis in a cat." Can Vet J 44(6): 509-510.

Beckers, E., I. Casselman, E. Soudant, S. Daminet, D. Paepe, L. Peelman and B. J. G. Broeckx (2022). "The prevalence of the ABCB1-1Δ variant in a clinical veterinary setting: The risk of not genotyping." PLoS One 17(8): e0273706.

Borowy CS, M. P. (2023). Antihistamine Toxicity. Treasure Island (FL), StatPearls Publishing.

Borsani, B., R. De Santis, V. Perico, F. Penagini, E. Pendezza, D. Dilillo, A. Bosetti, G. V. Zuccotti and E. D'Auria (2021). "The Role of Carrageenan in Inflammatory Bowel Diseases and Allergic Reactions: Where Do We Stand?" Nutrients 13(10).

Brooks, W. (2024). "Kennel Cough in Dog."

Butty, E. M., S. E. Suter, N. V. Chalifoux, A. M. Lynch, K. D. Mauro, R. B. Moyle, C. M. Ehrhardt, J. B. Robertson, C. A. Culler, L. A. Londoño, A. Vigani, Y. Ueda and M. A. Labato (2022). "Outcomes of nonsteroidal anti-inflammatory drug toxicosis treated with therapeutic plasma exchange in 62 dogs." Journal of Veterinary Internal Medicine 36(5): 1641-1647.

C., W. (2012). "Toxicology brief: phenylephrine ingestion in dogs: what's the harm? ."

Cafer, S., B. Bilgiç and M. E. Or (2024). "Is acetylsalicylic acid use in cats contraindicated or limited indicated?" Journal of Toxicological Studies 2(2): 1486.

Church, D. S. and M. K. Church (2011). "Pharmacology of antihistamines." World Allergy Organ J 4(3 Suppl): S22-27.

Chyka, P. A., E. A. R., M. A. S., C. Gwenn, B. L. L., N. L. S., W. A. D., C. D. J., C. E. Martin, S. E. J. and W. G. and Troutman (2007). "Dextromethorphan poisoning: An evidence-based consensus guideline for out-of-hospital management." Clinical Toxicology 45(6): 662-677.

Court, M. H. (2013). "Feline drug metabolism and disposition: pharmacokinetic evidence for species differences and molecular mechanisms." Vet Clin North Am Small Anim Pract 43(5): 1039-1054.

Davies, H., G. Pinchbeck, P. M. Noble, G. Diesel, M. Pirmohamed, N. Anderson and D. R. Killick (2022). "UK veterinary professionals' perceptions and experiences of adverse drug reaction reporting." Vet Rec 191(6): e1796.

Dowling, P. M. (2022, 2022/01). "Antitussive Drugs in Animals." 2022, from https://www.msdvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-respiratory-system/antitussive-drugs-in-animals.

Dowling, P. M. (2022, 2022/01). "Expectorants and Mucolytic Drugs in Animals." 2022, from https://www.msdvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-respiratory-system/expectorants-and-mucolytic-drugs-in-animals.

Dowling, P. M. (2023, 2023/05). "Drugs Used to Treat Diarrhea in Monogastric Animals." 2023, from https://www.msdvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-digestive-system/drugs-used-to-treat-diarrhea-in-monogastric-animals.

Dresser, R. and J. Frader (2009). "Off-label prescribing: a call for heightened professional and government oversight." J Law Med Ethics 37(3): 476-486, 396.

Dunayer, E. (2004). "Ibuprofen toxicosis in dogs, cats, and ferrets." Toxicology Brief

FDA, U. (2023). "The Ins and Outs of Extra-Label Drug Use in Animals: A Resource for Veterinarians."

FDA, U. (2023). "Over-the-Counter OTC | Nonprescription Drugs."

Fecht, S. and O. Distl (2008). "Review of prevalence, genetic aspects and adverse effects of the mdr1-1Delta mutation in dogs." Dtsch Tierarztl Wochenschr 115(6): 212-219.

Finno, C. J. (2020). "Veterinary Pet Supplements and Nutraceuticals." Nutr Today 55(2): 97-101.

Gehring, R., R. E. Baynes and J. E. Riviere (2006). "Application of risk assessment and management principles to the extralabel use of drugs in food-producing animals." J Vet Pharmacol Ther 29(1): 5-14.

Griebsch, C., E. Hall and V. R. Barrs (2022). "Effectiveness of aspirin vs. clopidogrel in dogs with immune mediated haemolytic anaemia evaluated by serial thromboelastography and platelet mapping." Vet J 287: 105882.

Hobi, S., P. M. Bęczkowski, R. Mueller, M. Tse and V. R. Barrs (2024). "Malassezia dermatitis in dogs and cats." The Veterinary Journal 304: 106084.

Howe, S. (2023). "Imodium® For Dogs: Can You Give Dogs Imodium?".

Hsieh, B. M. and A. K. Beets (2020). "Coughing in Small Animal Patients." Frontiers in Veterinary Science Volume 6 - 2019.

Immonen, H., M. R. Raekallio and A. R. Holmström (2023). "Promoting veterinary medication safety - Exploring the competencies of community pharmacy professionals in veterinary pharmacotherapy." Vet Anim Sci 21: 100310.

James A. Budde, D. M. M. (2023). Plumb's Veterinary Drug Handbook, 10th Edition, Wiley-Blackwell.

Krista Williams, M. W., Lynn Buzhardt (2023). "Over-the-Counter (OTC) Medications That May Be Safe for Dogs."

Kuehn, N. F. (2018, 2018/06). "Tracheobronchitis (Bronchitis) in Dogs." 2018, from https://www.msdvetmanual.com/dog-owners/lung-and-airway-disorders-of-dogs/tracheobronchitis-bronchitis-in-dogs.

Lautz, L. S., M. Z. Jeddi, F. Girolami, C. Nebbia and J. L. C. M. Dorne (2021). "Metabolism and pharmacokinetics of pharmaceuticals in cats (Felix sylvestris catus) and implications for the risk assessment of feed additives and contaminants." Toxicology Letters 338: 114-127.

Long, W. M., V. B. Sinnott, K. Bracker and D. Thomas (2017). "Use of 20% intravenous lipid emulsion for the treatment of loperamide toxicosis in a Collie homozygous for the ABCB1-1∆ mutation." J Vet Emerg Crit Care (San Antonio) 27(3): 357-361.

Lynch, S. S. (2023, 2025/03). "Overview of Over-the-Counter Medications." 2023, from https://www.msdmanuals.com/home/drugs/over-the-counter-medications/overview-of-over-the-counter-medications.

Mealey, K. L., J. G. Owens and E. Freeman (2023). "Canine and feline P-glycoprotein deficiency: What we know and where we need to go." J Vet Pharmacol Ther 46(1): 1-16.

Mekasha, Y. T., S. Nigussie, A. W. Mekonen, K. Berrie, A. Mulaw and M. G. Feleke (2024). "A narrative review of veterinary pharmacovigilance situations and prospects in East African countries." Front Vet Sci 11: 1430587.

Miller, L. (2014). Assuring Quality Care for Animals – Youth Food Animal Quality Assurance Curriculum Guide The Ohio State University.

Minich, D. M., M. Henning, C. Darley, M. Fahoum, C. B. Schuler and J. Frame (2022). "Is Melatonin the "Next Vitamin D"?: A Review of Emerging Science, Clinical Uses, Safety, and Dietary Supplements." Nutrients 14(19).

Mueller, R. S., T. Nuttall, C. Prost, B. Schulz and P. Bizikova (2021). "Treatment of the feline atopic syndrome – a systematic review." Veterinary Dermatology 32(1): 43-e48.

Muñoz, J., A. Nasaré, B. Cruz, J. Sousa, J. Messanelli, L. Leoni, T. Oliveira, B. Lopes, F. Nascimento, S. Novais, B. Serrano, P. Waziry and A. Fukushima (2023). "Feline toxicology: quick guide for consultation." 12: 43-49.

Myers, J., M. Hennessey, J. C. Arnold, K. D. McCubbin, T. Lembo, A. Mateus, F. E. Kitutu, I. Samanta, E. Hutchinson, A. Davis, B. T. Mmbaga, F. Nasuwa, M. Gautham and S. E. Clarke (2022). "Crossover-Use of Human Antibiotics in Livestock in Agricultural Communities: A Qualitative Cross-Country Comparison between Uganda, Tanzania and India." Antibiotics (Basel) 11(10).

NIDA. (2017). "Over-the-Counter Medicines DrugFacts."

Osweiler, G., et al. (2011). Blackwell’s five-minute veterinary consult clinical companion. Small Animal Toxicolog.

Osweiler, G. D. (2011). Blackwell's five-minute veterinary consult clinical companion: Small animal toxicology. Oxford, Wiley-Blackwell.

Peano, A., M. Beccati, E. Chiavassa and M. Pasquetti (2012). "Evaluation of the antifungal susceptibility of Malassezia pachydermatis to clotrimazole, miconazole and thiabendazole using a modified CLSI M27-A3 microdilution method." Veterinary dermatology 23: 131-135, e129.

Pitz, A. M., G. W. Park, D. Lee, Y. L. Boissy and J. Vinjé (2015). "Antimicrobial activity of bismuth subsalicylate on Clostridium difficile, Escherichia coli O157:H7, norovirus, and other common enteric pathogens." Gut Microbes 6(2): 93-100.

Plaza, P. I., G. M. Wiemeyer and S. A. Lambertucci (2022). "Veterinary pharmaceuticals as a threat to endangered taxa: Mitigation action for vulture conservation." Science of The Total Environment 817: 152884.

Pottel, J., D. Armstrong, L. Zou, A. Fekete, X. P. Huang, H. Torosyan, D. Bednarczyk, S. Whitebread, B. Bhhatarai, G. Liang, H. Jin, S. N. Ghaemi, S. Slocum, K. V. Lukacs, J. J. Irwin, E. L. Berg, K. M. Giacomini, B. L. Roth, B. K. Shoichet and L. Urban (2020). "The activities of drug inactive ingredients on biological targets." Science 369(6502): 403-413.

Rogasch, N. C., C. Zipser, G. Darmani, T. P. Mutanen, M. Biabani, C. Zrenner, D. Desideri, P. Belardinelli, F. Müller-Dahlhaus and U. Ziemann (2020). "The effects of NMDA receptor blockade on TMS-evoked EEG potentials from prefrontal and parietal cortex." Sci Rep 10(1): 3168.

Rossbach, K., A. Strattner and D. Meurer (2016). "The use of H1-antihistamines in veterinary medicine." 97: 1012-1020.

Sartor, L. L., S. A. Bentjen, L. Trepanier and K. L. Mealey (2004). "Loperamide toxicity in a collie with the MDR1 mutation associated with ivermectin sensitivity." J Vet Intern Med 18(1): 117-118.

Schulz, J. A., A. M. S. Hartz and B. Bauer (2023). "ABCB1 and ABCG2 Regulation at the Blood-Brain Barrier: Potential New Targets to Improve Brain Drug Delivery." Pharmacol Rev 75(5): 815-853.

Shipstone, M. (2022, 2022/04). "Antihistamines for Integumentary Disease in Animals." 2022, from https://www.msdvetmanual.com/pharmacology/systemic-pharmacotherapeutics-of-the-integumentary-system/antihistamines-for-integumentary-disease-in-animals.

Shugg, R. (2022). "Which Over-the-Counter Human Medications Are Safe for Dogs?".

Siroká, Z. (2012). "[Important toxic and undesirable effects of medicaments in animals from the pharmacists viewpoint]." Ceska Slov Farm 61(5): 222-228.

Sobczak, M., M. Sałaga, M. A. Storr and J. Fichna (2014). "Physiology, signaling, and pharmacology of opioid receptors and their ligands in the gastrointestinal tract: current concepts and future perspectives." Journal of Gastroenterology 49(1): 24-45.

Taylor, C. P., S. F. Traynelis, J. Siffert, L. E. Pope and R. R. Matsumoto (2016). "Pharmacology of dextromethorphan: Relevance to dextromethorphan/quinidine (Nuedexta®) clinical use." Pharmacology & Therapeutics 164: 170-182.

Taylor, J. G., S. Ayosanmi and S. S. Sansgiry (2023). "Consumer Impressions of the Safety and Effectiveness of OTC Medicines." Pharmacy (Basel) 11(2).

Thomazini, V. C., G. M. da Cunha, N. M. Guimarães, S. D. Saleme, R. C. G. de Melo, G. A. de Paula, S. G. Carvalho, M. Chorilli, C. Dos Santos Giuberti and J. C. O. Villanova (2024). "Impact of concerning excipients on animal safety: insights for veterinary pharmacotherapy and regulatory considerations." Daru 32(1): 289-305.

Tomanic, D., D. Stojanovic, B. Belić, I. Davidov, N. Novakov, M. Radinovic, N. Kladar and Z. Kovacevic (2021). "Off label use of human approved drugs in treatment of dogs in the Republic of Serbia." Pol J Vet Sci 24(3): 399-407.

Torfs, E. and G. Brackman (2021). "A perspective on the safety of parabens as preservatives in wound care products." Int Wound J 18(2): 221-232.

Van Norman, G. A. (2023). "Off-Label Use vs Off-Label Marketing of Drugs: Part 1: Off-Label Use-Patient Harms and Prescriber Responsibilities." JACC Basic Transl Sci 8(2): 224-233.

Walden, L. A. (2021). "Cold and Flu Medications Dangerous for Pets."

Wiegand, T. J. (2024). Guaifenesin. Encyclopedia of Toxicology (Fourth Edition). P. Wexler. Oxford, Academic Press: 93-97.

DOI: https://doi.org/10.22146/ijvs.v4i2.106709