Update (June 19, 2026): Ondansetron Maintains Cardiovascular Stability and Avoids NT-proBNP Elevation Versus Atropine in Canine Anesthesia

TL;DR. A 2026 randomised controlled study found ondansetron maintained cardiovascular stability and prevented NT-proBNP elevation during canine anesthesia, suggesting it may serve as an antiemetic adjuvant that avoids the myocardial stress associated with atropine.

What just dropped

• Costa et al. 2026 (Vet Sci, open access; PMID 41745913) enrolled 66 female ASA I dogs in a randomised, controlled, observer-blinded study comparing atropine, ondansetron, or no autonomic-modulating drug during elective surgery under anesthesia. (https://europepmc.org/articles/PMC12944856)
• Dogs treated with ondansetron maintained stable cardiovascular values throughout the procedure, with no episodes of low heart rate or excessive increases in heart rate.
• Atropine induced marked and sustained elevation in heart rate and higher arterial pressures.
• NT-proBNP (cardiac biomarker) increased significantly 48 h post-surgery in the atropine group but remained unchanged in the ondansetron group, indicating the absence of additional myocardial stress.
• Authors suggest ondansetron could represent a useful component of multimodal anesthetic protocols, particularly in dogs where excessive cardiac stimulation should be avoided.

Context

Ondansetron is a selective 5-HT3 receptor antagonist used in human medicine primarily as an antiemetic and as a prevention of vagal bradycardia during surgery. In dogs, its antiemetic role has been established, but its utility as an anesthetic adjuvant to maintain autonomic balance has received less formal study. This study is the first prospective randomised study quantifying NT-proBNP as an objective cardiac stress indicator with ondansetron vs atropine in canine anesthesia.

The finding that atropine - routinely used to prevent vagally-induced bradycardia - is associated with significantly elevated NT-proBNP (reflecting myocardial wall stress) is clinically relevant. The mechanism is atropine's chronotropic/inotropic effects increasing myocardial oxygen demand. Ondansetron's ability to maintain heart rate stability without this signal may be particularly relevant in cardiac-compromised patients, though study participants were ASA I dogs; extrapolation to cardiac disease patients requires further study.

What this changes in maropitant-dogs-cats-vomiting (https://www.thevoyage.ai/forvets/knowledge/maropitant-dogs-cats-vomiting)

This study broadens the perianesthetic antiemetic discussion beyond maropitant. Maropitant (NK1 antagonism), ondansetron (5-HT3 antagonism), and metoclopramide represent distinct receptor targets. The Costa 2026 data position ondansetron as a dual-function agent - antiemetic and autonomic modulator - with a potential cardiac safety advantage over atropine as a vagolytic in surgical protocols. Multimodal antiemetic combinations and their drug interactions with other peri-anaesthetic agents warrant further study.

References

1. Costa GL, Iannelli NM, Bruno F, et al. Evaluation of the Cardiovascular and Serotonergic Modulatory Effects of Ondansetron in Healthy Dogs Under Anesthesia. Vet Sci. 2026;13(2):119. https://europepmc.org/articles/PMC12944856
2. Golbeli Bedir A, Yanmaz LE, Okur S, et al. The Effect of Maropitant, Ondansetron and Metoclopramide on Dexmedetomidine-Induced Vomiting in Cats. Vet Med Sci. 2025;11(1):e70152. https://europepmc.org/articles/PMC11720719

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