Herndon AK, Quimby JM, Sieberg LG, et al. Preliminary pharmacokinetics of intravenous and subcutaneous dolasetron and pharmacodynamics of subcutaneous dolasetron in healthy cats. J Feline Med Surg. 2018 Aug;20(8):721-727.
Medical management of vomiting in sick cats is an important part of veterinary care. Dolasetron is a 5-HT3 receptor antagonist that blocs nausea and vomiting in both the gastrointestinal tract and central nervous system. Dolasetron was developed to treat chemotherapy-induced vomiting in people and has been recommended as an anti-vomiting therapy in cats.
In this study, the authors’ objectives were to evaluate the pharmacokinetics (PK) of subcutaneous (SC) and intravenous (IV) dolasetron and the pharmacodynamics (PD) of SC dolasetron in healthy cats. An empirical dose has been described as 0.6-1.0 mg/kg IV once daily but PK and PD studies have not been done to determine the recommended therapeutic dosage.
In the PK portion of the study, dolasetron was administered at 0.8 mg/kg IV in five cats and 0.8 mg/kg SC in four cats. Dolasetron was quickly metabolized to the predominant active ingredient, hydrodolasetron, with only two cats for each route of administration having measurable concentrations beyond 2 hours. Looking at the PD part of the study, there was no statistical difference in number of vomiting events, time of onset of vomiting or visual nausea score compared to a control of saline.
The authors noted that the administration of 0.8 mg/kg dolasetron does not maintain overall serum concentrations of the active metabolite, hydrodolasetron, for 24 hours. Also, administration of dolasetron at 0.8 mg/kg and 1 mg/kg did not prevent vomiting in cats. The results show that additional feline studies are needed to determine if a higher dose is efficacious. Such studies are needed to determine if drugs are effective anti-vomiting drugs treating cat patients at the dose veterinarians frequently use in clinical practice. (VT)
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