Antiemetic agents

Vomiting is defined as the ejection of food and/or fluid from the digestive tract (mouth, oesophagus, or stomach) and is a common clinical sign in cats.

Vomiting in cats is of concern if it occurs more frequently than once every three or four days, contains blood (hematemesis), hair or parasites (esp Ollulanus tricuspis).

  • See Physiology of vomiting

Table 1. Antiemetic agents used in cats[1].

Drugs Mechanism of action Dosage Indications
Chlorpromazine Dopaminergic D2 receptor antagonism 0.5 mg/kg IM q 8 hrs Sedation, motion sickness
Cimetidine H2 receptor antagonism 2.5-5.0 mg/kg IV q 8 hrs Uremia-associated emesis
Cisapride 5HT4 receptor antagonism 0.1-0.5 mg/kg PO q 12-24 hrs Irritable bowel disease-associated emesis, gastroparesis, megacolon
Cyclizine H2 receptor antagonism 4 mg/kg IM q 8hrs vomiting associated with travel
Dextromethorphan NMDA receptor antagonist 0.5 – 2.0 mg/kg orally q 6 – 8 hours motion sickness
Dimenhydrinate H1 receptor antagonism 12.5 mg/kg PO q 8 hrs Chronic renal disease
Diphenhydramine H1 receptor antagonism 2-4 mg/kg PO, IM q 8 hrs CNS depression, xerostomia
Dolasetron 5HT3 receptor antagonism 0.6-10 mg/kg IV, PO q 24 hrs Chemotherapy-associated emesis
Famotidine H2 receptor antagonism 0.5 mg/kg IV, PO q 12 – 24 hrs Uremia-associated emesis, pancreatitis
Granisetron 5HT3 receptor antagonism 0.1-0.5 mg/kg IV, PO q 12-24 hrs Chemotherapy-associated emesis
Ketamine NMDA receptor antagonist 0.5 – 2.0 mg/kg orally q 6 – 8 hours cisplatin-induced emesis
Maropitant NK1 receptor antagonism 0.5-1.0 mg/kg SQ q 24 hrs Chemotherapy-associated emesis, pancreatitis
Meclizine H1 receptor antagonism 4 mg/kg PO q 24 hrs Uraemia-associated emesis
Metoclopramide Dopaminergic D2 receptor antagonism (CNS effects) 1-2 mg/kg IV infusion;
Adrenergic antagonist (Prokinetic effects) 0.2-0.5 mg/kg PO, SQ q 8 hrs Chemotherapy-associated emesis, pancreatitis
Mirtazepine 5HT3 receptor antagonism, H1 receptor antagonism 3-4 mg/cat PO q 72 hrs Uremia-associated emesis, pancreatitis
Omeprazole Proton pump inhibitor 0.5-1.0 mg/kg orally once daily gastritis, gastroesophageal reflux
Ondansetron 5HT3 receptor antagonism 0.1-1.0 mg/kg PO q 12-24 hrs Chemotherapy-associated emesis
Prochlorperazine Mixed α12 antagonism; dopaminergic D2 receptor antagonism 0.1 mg/kg IM q 6-12 hrs Pre-anaesthetic sedation, motion sickness
Promethazine H1 receptor antagonism 2 mg/kg PO or IM q 24 hrs Motion sickness
Ranitidine H2 receptor antagonism 2 mg/kg/day continuous rate infusion; 2.5 mg/kg IV q 8 hrs Gastritis- and uraemia-associated emesis


  1. ↑ Allenspach, K & Chan, DL (2010) Antiemetic therapy. In August, JR (Ed): COnsultations in feline internal medicine. Vol 6. Elsevier Saunders, Philadelphia. pp:232

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