Palonosetron Ribosepharm (Palonosetron)

Palonosetron is a selective 5‑HT3 receptor antagonist indicated for the prevention of nausea and vomiting in several clinical settings.

• Chemotherapy‑induced nausea and vomiting (CINV): Provides long‑lasting protection against acute and delayed episodes.
• Post‑operative nausea and vomiting (PONV): Reduces the incidence of nausea and vomiting after general anesthesia.
• Radiotherapy‑induced nausea and vomiting: Helps control nausea associated with radiation treatment.
• Antiemetic prophylaxis for highly emetogenic chemotherapy regimens: Offers enhanced control when used with other antiemetics.

• Palonosetron binds with high affinity to the serotonin 5‑HT3 receptor sites located on vagal afferent nerves in the gastrointestinal tract and the chemoreceptor trigger zone. By blocking these receptors, it prevents serotonin‑mediated activation of the vomiting centre in the brain, delivering a prolonged anti‑emetic effect that lasts up to 72 hours after a single dose.

Palonosetron may cause adverse reactions, most of which are mild to moderate in intensity.

Common Side Effects

• Headache: mild to moderate intensity.
• Constipation: occasional bowel habit changes.
• Fatigue: general tiredness.
• Dizziness: transient light‑headedness.
• Injection site erythema: mild redness at the administration site.

Serious or Rare Side Effects

• Allergic reaction: rash, itching, swelling, or anaphylaxis.
• Cardiac arrhythmia: QT‑interval prolongation in susceptible individuals.
• Severe constipation or bowel obstruction.
• Serotonin syndrome: rare when combined with other serotonergic agents.
• Hypotension: notable drop in blood pressure post‑administration.

When using Palonosetron, clinicians should consider several safety aspects.

• Cardiac monitoring: assess baseline ECG in patients with known QT prolongation risk.
• Concomitant serotonergic drugs: evaluate for potential serotonin syndrome.
• Renal or hepatic impairment: adjust monitoring as needed.
• Pregnancy and lactation: use only if clearly needed; weigh benefits against risks.
• Pediatric use: safety and efficacy not established in children.
• Store at ambient temperature: keep in original container, protect from moisture and light.

Palonosetron can interact with other medications, requiring attention to avoid reduced efficacy or increased toxicity.

Major Interactions (Avoid)

• QT‑prolonging agents: may compound risk of cardiac arrhythmias.
• Strong CYP3A4 inhibitors: may increase palonosetron plasma levels.

Moderate Interactions (Monitor Closely)

• Other antiemetics (e.g., dexamethasone, NK‑1 antagonists): may require dose adjustments.
• Serotonergic agents (e.g., SSRIs, SNRIs): monitor for serotonin syndrome signs.
• Diuretics: watch for electrolyte shifts that could affect cardiac rhythm.
• Antifungal azoles: potential CYP‑mediated interaction.
• Calcium channel blockers: may influence cardiac conduction.