Prevention of chemotherapy-induced nausea and vomiting (CINV)
Prevention of postoperative nausea and vomiting (PONV)
Dosage
Adults (CINV): 0.25 mg IV as a single dose before chemotherapy
Adults (PONV): 0.075 mg IV immediately before induction of anesthesia
Pediatric (≥1 month): 20 µg/kg IV, max 1.5 mg/dose (for CINV)
Note: Single dose is usually sufficient due to long half-life (~40 hours).
Route of Administration
Intravenous (IV)
Mechanism of Action
Palonosetron is a selective 5-HT3 receptor antagonist that blocks serotonin signaling in the chemoreceptor trigger zone and gastrointestinal tract, preventing nausea and vomiting. It has a longer half-life and higher receptor binding affinity compared to other 5-HT3 antagonists.
Common Adverse Effects
Headache
Constipation
Dizziness
Fatigue
Serious Adverse Effects
QT interval prolongation (rare)
Severe hypersensitivity reactions (rare)
Serotonin syndrome (very rare, if combined with other serotonergic drugs)
Contraindications
Hypersensitivity to palonosetron or other 5-HT3 antagonists
Congenital long QT syndrome
Precautions
Monitor ECG in patients at risk for QT prolongation
Use caution in severe hepatic impairment
Avoid co-administration with other QT-prolonging drugs if possible
Drug Interactions
Other QT-prolonging drugs – additive risk of arrhythmia
Serotonergic drugs – monitor for serotonin syndrome
CYP2D6, CYP3A4 substrates – monitor for altered metabolism
Pregnancy & Lactation
Use only if clearly needed; limited human data available. Excreted in small amounts in breast milk.
Patient Counseling
Single IV dose is usually sufficient; follow healthcare provider instructions
Report palpitations, dizziness, or allergic reactions
Do not self-administer additional doses without medical advice