Palonosetron is a 5-HT3 receptor antagonist with a strong binding affinity for this receptor and little or no affinity for other receptors. Cancer chemotherapy may be associated with a high incidence of nausea and vomiting, particularly when certain agents, such as cisplatin, are used. 5-HT3 receptors are located on the nerve terminals of the vagus in the periphery and centrally in the chemoreceptor trigger zone of the area postrema. It is thought that chemotherapeutic agents produce nausea and vomiting by releasing serotonin from the enterochromaffin cells of the small intestine and that the released serotonin then activates 5-HT3 receptors located on vagal afferents to initiate the vomiting reflex. See package insert for complete information.

Palonosetron Hydrochloride (HCl) Injection is a serotonin-3 (5-HT3) receptor antagonist indicated in adults for:
• Moderately emetogenic cancer chemotherapy: prevention of acute and delayed nausea and vomiting associated with initial and repeat courses.
• Highly emetogenic cancer chemotherapy: prevention of acute nausea and vomiting associated with initial and repeat courses.
• Prevention of postoperative nausea and vomiting (PONV) for up to 24 hours following surgery. Efficacy beyond 24 hours has not been demonstrated.
Palonosetron Hydrochloride Injection is indicated in pediatric patients aged 1 month to less than 17 years for:
• Prevention of acute nausea and vomiting associated with initial and repeat courses of emetogenic cancer chemotherapy, including highly emetogenic cancer chemotherapy.

Chemotherapy Induced Nausea and Vomiting
• Adult Dosage: a single 0.25 mg I.V. dose administered over 30 seconds. Dosing should occur approximately 30 minutes
before the start of chemotherapy.

Postoperative Nausea and Vomiting 
• Adult Dosage: a single 0.075 mg I.V. dose administered over 10 seconds immediately before the induction of anesthesia.

The most common adverse reactions in:
• chemotherapy-induced nausea and vomiting (≥5%) are: headache and constipation.
• postoperative nausea and vomiting (≥2%) are: QT prolongation, bradycardia, headache, and constipation.

Hypersensitivity to the drug or any of its components.

• Hypersensitivity reactions, including anaphylaxis, have been reported with or without known hypersensitivity to other selective 5-HT3 receptor antagonists.
• Serotonin syndrome has been reported with 5-HT3 receptor antagonists alone but particularly with concomitant use of serotonergic drugs.