Dosage of Pimobendan in Domestic Cats.

Background: Available evidence suggests that pimobendan may provide clinical benefits in the treatment of heart diseases in cats. However, its dosage is based on studies conducted in dogs, raising concerns due to differences in plasma concentrations between species. Review Question: What is the dosage of pimobendan used in domestic cats, either healthy or with heart disease? Methods: Searches in the PubMed, Web of Science, Scopus, and ScienceDirect databases were conducted between October and November 2024, a period corresponding to the execution of the search strategy. Full-text articles were included without restrictions regarding language, country, or year of publication, while gray literature was excluded. Results: Out of 371 articles screened, 15 were excluded due to duplication or lack of relevance, resulting in 10 studies being included in the final review. Pimobendan dosages ranged from 0.125 mg/kg to 0.5 mg/kg, with oral administration being predominant, typically every 12 h. Some studies used single doses to evaluate the drug's pharmacodynamics. Beneficial effects observed included improved cardiac output, enhanced left ventricular function, and reduced risk of thrombi. Common adverse effects were anorexia, vomiting, lethargy, hypotension, and arrhythmias, particularly tachycardia (4/10). The studies showed some risk of bias, such as lack of detailed information on sex, weight, and adverse effects in cats, heterogeneity in study populations, variability in pimobendan doses, and insufficient control of cardiac disease conditions. Conclusion and Clinical Relevance: Pimobendan was well tolerated in cats, with only isolated and no clinically relevant adverse effects reported, at doses ranging from 0.24 to 0.5 mg/kg or 1.25 mg/cat, with oral administration every 12 h being the recommended regimen.