Palonan (Palonosetron)

Palonosetron is used in the management of nausea and vomiting through its action on serotonin pathways.

• Chemotherapy‑induced nausea and vomiting (CINV): helps prevent the acute and delayed phases of CINV.
• Post‑operative nausea and vomiting (PONV): reduces the incidence of nausea and vomiting after surgery.
• Radiotherapy‑induced nausea and vomiting: assists in controlling the nausea associated with radiation treatment.
• Antiemetic prophylaxis for high‑risk patients: provides additional protection for patients identified as high‑risk for severe emesis.
• Adjunctive therapy in combination with other antiemetics: used alongside other agents to enhance overall anti‑emetic control.
• Support for patients receiving highly emetogenic chemotherapy regimens.

• Palonosetron selectively blocks the 5‑HT3 receptors in the central nervous system and peripheral vagal nerve terminals, inhibiting serotonin‑mediated signaling that triggers the vomiting reflex. By binding with high affinity and a prolonged half‑life, it provides extended protection against both acute and delayed emesis without activating the receptor.

Palonosetron is generally well‑tolerated, but adverse reactions can occur.

Common Side Effects

• Headache 
• Constipation 
• Fatigue 
• Dizziness 
• Injection site discomfort 
• Diarrhea 

Serious or Rare Side Effects

• Severe hypersensitivity reactions (anaphylaxis, angio‑edema) 
• QT‑interval prolongation 
• Cardiac arrhythmias 
• Serotonin syndrome (when combined with serotonergic agents) 
• Severe constipation or intestinal obstruction 
• Neuro‑muscular weakness or respiratory depression.

Palonan should be used with consideration of patient‑specific factors and monitoring requirements.

• Pregnancy: safety data are limited; use only if the potential benefit justifies the potential risk.
• Breastfeeding: it is unknown whether the drug passes into human milk; caution is advised.
• Cardiac risk: monitor patients with known QT‑prolongation or electrolyte disturbances.
• Concomitant serotonergic drugs: assess for additive serotonergic effects.
• Renal or hepatic impairment: dose adjustment may be needed based on clinical judgment.
• Store at 2-8°C: keep refrigerated ; protect from light ; do not freeze or shake.

Palonosetron may interact with several drug classes that affect cardiac rhythm or serotonin pathways.

Major Interactions (Avoid)

• Drugs that prolong the QT interval such as certain antiarrhythmics, macrolide antibiotics ; 
• Strong serotonergic agents (e.g., SSRIs, MAO‑inhibitors) that could increase serotonin syndrome risk.

Moderate Interaction (Monitor Closely):

• CYP enzyme inducers or the C c t t c C c t C c c C t C c c C C C C C C C C C C C C C C C C

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