Palonosetron is indicated for:
Palonosetron is a selective 5-HT3 receptor antagonist with high binding affinity for the receptor and minimal or no affinity for other receptors. Chemotherapy drugs are believed to cause nausea and vomiting by releasing serotonin from enterochromaffin cells in the small intestine. This serotonin activates 5-HT3 receptors located on vagal nerve terminals in the periphery and in the chemoreceptor trigger zone of the area postrema in the central nervous system, initiating the vomiting reflex. Postoperative nausea and vomiting is caused by multiple patient-related, surgical, and anesthetic factors and involves serotonin release and a cascade of neuronal events in both the central nervous system and gastrointestinal tract. The 5-HT3 receptor plays a key role in the emetic response. Palonosetron works by blocking serotonin action at 5-HT3 receptors, mainly in the gastrointestinal tract and possibly also in the brain.
Pharmacokinetics: Palonosetron shows linear dose-proportional pharmacokinetics over a dose range of 1–90 mcg/kg in both healthy subjects and cancer patients. After intravenous administration in cancer patients, the mean peak plasma concentration (Cmax) ranges from 0.89 to 336 ng/mL, and the area under the curve (AUC0–∞) ranges from 13.8 to 957 ng·h/mL. It has a volume of distribution of approximately 6.9–7.9 L/kg, with about 62% plasma protein binding. Around 50% is metabolized into two inactive metabolites with less than 1% 5-HT3 antagonist activity. Metabolism occurs via the liver mainly through CYP2D6, CYP3A4, and CYP1A2 enzymes, while about 40% is excreted unchanged in urine within 144 hours. Total body clearance is approximately 160 ± 35 mL/h/kg, and renal clearance is 66.5 ± 18.2 mL/h/kg in healthy individuals. Palonosetron has a long elimination half-life of about 40 hours and a strong receptor binding affinity.
Usual dosage: Adult tablet dosage: 0.5 mg daily. Adult IV dosage: A single IV dose of 0.075 mg should be administered over 10 seconds.
Chemotherapy-induced nausea and vomiting: Adult tablet dosage: 0.5 mg administered approximately 1 hour prior to the start of chemotherapy. Adult IV dosage: A single IV dose of 0.25 mg should be administered over 30 seconds approximately 30 minutes before the start of chemotherapy.
Radiotherapy-induced nausea and vomiting: A single IV dose of 0.25 mg should be administered over 30 seconds approximately 30 minutes before each week of radiation fraction.
Post-operative nausea and vomiting: A single IV dose of 0.075 mg should be administered over 10 seconds immediately before induction of anesthesia.
Children dosage: (1 month to 17 years): A single IV dose at 20 mcg/kg body weight. Which maximum dose is 1.5 mg.
In controlled clinical trials, Palonosetron injection has been safely used with corticosteroids, analgesics, antiemetics/antinauseants, antispasmodics, and anticholinergic agents. Palonosetron did not reduce the antitumor activity of cisplatin, cyclophosphamide, cytarabine, doxorubicin, or mitomycin C in animal tumor models. Co-administration with metoclopramide does not show significant pharmacokinetic interaction. In vitro studies show that palonosetron does not inhibit CYP1A2, CYP2A6, CYP2B6, CYP2C9, CYP2D6, CYP2E1, or CYP3A4/5 (CYP2C19 not evaluated), nor does it induce CYP1A2, CYP2D6, or CYP3A4/5. Therefore, clinically significant drug interactions are unlikely.
Palonosetron is contraindicated in patients with known hypersensitivity to the drug or any of its components.
The most common adverse effects are headache and constipation.
Pregnancy category B. It is not known whether Palonosetron is excreted in human breast milk.
Elderly: No dose adjustment is required in patients over 65 years.
Children (1 month to 10 years): Single IV dose of 20 mcg/kg body weight, maximum 1.5 mg.
Renal & Hepatic impairment: No dose adjustment required.
There is no known antidote. Overdose should be managed with supportive care.
Anti-emetic drugs
Store in a cool, dry place, protected from light.
What is Palonosetron for?
What does Palonosetron do?
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