Dolasetron: veterinary dose and monograph

At a glance

Drug class

Antiemetic

Also known as

Anzemet, Dolasetron mesylate

Species with doses

Dogs and Cats

General dose range

0.5–1 mg/kg IV q24h — check the species tables for the indication

Routes

IV

Last reviewed

1 October 2026

Indications

• Chemotherapy-induced nausea and vomiting
• Refractory vomiting — parvoviral enteritis, pancreatitis, gastroenteritis
• Peri-operative / drug-induced nausea and vomiting
• Antiemesis where a once-daily 5-HT3 antagonist is convenient

Dolasetron dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

Dogs

• Moderate–severe vomiting (incl. chemo/parvo): Papich 5e: prevention 0.6 mg/kg IV, SC or PO q12–24h (or 1.2 mg/kg once); treatment 1 mg/kg IV or PO once daily — oral absorption is low. Plumb’s p.434: 0.6 mg/kg IV once daily for chemotherapy (Dowling); 0.5 mg/kg PO, SC or IV q24h (Encarnacion); 0.6–1 mg/kg PO q12h (Washabau).

Cats

• Moderate–severe vomiting: Papich 5e (dogs and cats): prevention 0.6 mg/kg q12–24h; treatment 1 mg/kg once daily IV or PO. Plumb’s p.434: 0.6 mg/kg IV q12–24h; 0.6–1 mg/kg PO q12h (Encarnacion; Washabau).

Contraindications

Known hypersensitivity to 5-HT3 antagonists. Significant cardiac conduction disease / marked QT prolongation (high IV doses prolong QT). GI obstruction (treat the cause, not just the vomiting). Caution with other QT-prolonging or serotonergic drugs.

Adverse effects

• Generally well tolerated
• Constipation, mild sedation
• QT prolongation / cardiac conduction effects at high IV doses
• Injection-site discomfort

Drug interactions

• Other QT-prolonging drugs: additive QT prolongation (caution, especially high IV doses)
• Serotonergic drugs: theoretical serotonin-related interaction
• Maropitant/ondansetron: combined for refractory vomiting (different/overlapping mechanisms)

Pregnancy and lactation

Limited data; use if clearly needed for significant vomiting.

Monitoring

• Antiemetic response (control of vomiting)
• Constipation; ECG if high IV doses or cardiac risk
• Address the underlying cause of vomiting (not just symptom control)

Toxicity and overdose

Wide margin; overdose causes constipation and, at high IV doses, dose-related QT prolongation and cardiac-conduction effects (the reason the high-dose human formulation was restricted). Generally well tolerated at antiemetic doses.

Management: No specific antidote. Supportive care; ECG monitoring for QT/conduction effects at high doses; manage constipation. Effects are generally mild. Decontaminate large recent oral ingestions.

Clinical pearls

• A once-daily 5-HT3 antiemetic (ondansetron-class) — handy for chemotherapy- and GI-injury-induced vomiting (parvo, pancreatitis), often combined with maropitant for refractory cases
• Its long-acting active metabolite allows convenient once-daily dosing
• At high IV doses it can prolong QT — use cautiously in cardiac patients/with other QT-prolonging drugs
• Treat the underlying cause; 5-HT3 antagonists control the symptom

Mechanism of action

Dolasetron (via its active metabolite hydrodolasetron) selectively antagonises serotonin 5-HT3 receptors on vagal afferent nerves in the GI tract and in the chemoreceptor trigger zone/vomiting centre — blocking the serotonin-mediated emetic signalling that is especially important in chemotherapy- and GI-injury-induced vomiting. The long half-life of the active metabolite permits once-daily dosing.

Formulations and products

• Injection 20 mg/mL
• 50 / 100 mg tablet
• Anzemet / Dolasetron — 20 mg/mL injection; 50 / 100 mg tablet, Injection / tablet (human-label)

Storage

Injection/tablets: 15–30 °C, protect from light.

Before you use this dose

Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

Other antiemetics

• Maropitant
• Ondansetron

Frequently asked questions