Granisetron
Granisetron is a selective serotonin 5-HT3-receptor antagonist used as an antiemetic. Its principal veterinary application is prevention or treatment of severe vomiting, particularly around emetogenic chemotherapy in dogs and cats. Veterinary clinical experience is more limited than for some other antiemetics, and use for individual gastrointestinal disorders is often empirical.
Group
5-HT3 antagonist antiemetic
Mechanism of Action
Granisetron blocks 5-HT3 receptors on gastrointestinal vagal afferents and in central emetic pathways. Injury or stimulation of intestinal enterochromaffin cells can release serotonin, activating these receptors and relaying an emetic signal to the brainstem. Receptor blockade interrupts that signaling and reduces vomiting driven by susceptible peripheral and central triggers.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Antiemesis | 0.01 mg/kg | IV | ||
| Antiemesis | 0.02 mg/kg | PO | Oral regimen extrapolated; frequency not established in the source. | |
| Antiemesis | 0.1–0.5 mg/kg | PO, IV | Every 12 h | Alternative regimen in the additional source; not a unit conversion of the lower-dose regimen. |
Cat
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Antiemesis | 0.01 mg/kg | IV | ||
| Antiemesis | 0.02 mg/kg | PO | Oral regimen extrapolated; frequency not established in the source. | |
| Antiemesis | 0.1–0.5 mg/kg | PO, IV | Every 12 h | Alternative regimen in the additional source; not a unit conversion of the lower-dose regimen. |
| Pancreatitis-associated nausea | 0.1–0.5 mg/kg | PO, IV | Every 12–24 h |
Indications
- Prevention or treatment of chemotherapy-associated vomiting in dogs and cats.
- Adjunctive treatment of selected severe or persistent vomiting associated with gastrointestinal disease in small animals; granisetron-specific clinical evidence is limited.
Contraindications
- Veterinary safety data are limited.
Interactions
- May be combined with maropitant acting at a different receptor.
Adverse effects
- No specific animal adverse profile established in the supplied source.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Granisetron 1 mg | Tablet | 1 mg / tablet | PO |
| Granisetron injection 1 mg/mL | Injection | 1 mg / mL | IV |
| Granisetron oral solution 0.5 mg/mL | Oral Liquid | 0.5 mg / mL | PO |
| Granisetron oral solution 1 mg/5 mL Granisetron base-equivalent strength; corresponds to 1.12 mg hydrochloride per 5 mL. | Oral Liquid | 1 mg / 5 mL | PO |
| Granisetron injection 0.1 mg/mL Granisetron base-equivalent strength; corresponds to 0.112 mg hydrochloride/mL. | Injection | 0.1 mg / mL | IV |
Monitoring and Administration
Assess vomiting control and hydration. Veterinary doses are largely empirical.
Single-use and multidose vial handling differ; do not apply a universal 30-day opened-vial rule.