Prevention of chemotherapy-induced nausea and vomiting (CINV)
Prevention of radiotherapy-induced nausea and vomiting (RINV)
Postoperative nausea and vomiting (PONV)
Dosage
Adults: 1 mg IV or 2 mg orally once daily (CINV prevention)
Pediatric: 40 µg/kg IV (max 3 mg per dose) for children ≥2 years
Note: Adjust dosing in patients with severe hepatic impairment.
Route of Administration
Oral (tablet, solution), Intravenous (IV)
Mechanism of Action
Granisetron selectively blocks 5-HT3 receptors in the central nervous system (chemoreceptor trigger zone) and gastrointestinal tract, preventing serotonin-mediated stimulation of the vomiting reflex.
Common Adverse Effects
Headache
Constipation
Diarrhea
Fatigue
Serious Adverse Effects
QT prolongation and arrhythmias (rare)
Severe hypersensitivity reactions (rare)
Serotonin syndrome (rare, if combined with serotonergic drugs)
Contraindications
Hypersensitivity to granisetron or other 5-HT3 antagonists
Congenital long QT syndrome
Precautions
Monitor ECG in patients with risk factors for QT prolongation
Use caution in hepatic impairment
Avoid co-administration with other QT-prolonging drugs if possible
Drug Interactions
Other QT-prolonging drugs – additive risk of arrhythmia
Serotonergic drugs – caution for serotonin syndrome
CYP3A4 inhibitors/inducers – may alter granisetron metabolism
Pregnancy & Lactation
Use only if clearly needed; limited human data available. Excreted in breast milk – use caution.
Patient Counseling
Take oral dose 30–60 minutes before chemotherapy
Report palpitations, fainting, or severe dizziness
Follow all prescribed antiemetic regimens to prevent nausea and vomiting