Palonosetron Sala (Palonosetron)

Palonosetron is a selective 5‑HT3 receptor antagonist used in the management of chemotherapy‑induced and postoperative nausea and vomiting.

• Chemotherapy‑induced nausea and vomiting (CINV): helps prevent acute and delayed episodes in patients receiving highly emetogenic chemotherapy.
• Post‑operative nausea and vomiting (PONV): reduces the incidence of nausea and vomiting after general anesthesia.
• Radiotherapy‑induced nausea and vomiting: provides prophylaxis when radiotherapy involves the abdomen or pelvis.
• Antiemetic prophylaxis for pregnancy‑related hyperemesis: used off‑label in some regions for severe nausea when other treatments fail.

• Palonosetron binds with high affinity to the 5‑HT3 receptors located on vagal afferent nerves in the gastrointestinal tract and the chemoreceptor trigger zone of the brain. By blocking serotonin from activating these receptors, it inhibits the neural signaling cascade that triggers the vomiting reflex, providing prolonged anti‑emetic protection that can last up to 72 hours after a single dose.

Palonosetron is generally well tolerated, but adverse reactions have been reported.

Common Side Effects

• Headache: mild to moderate intensity.
• Constipation: occasional bowel movement changes.
• Fatigue: feeling of tiredness without exertion.
• Dizziness: transient light‑headed sensations.
• 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 intestinal obstruction.
• Serotonin syndrome: rare when combined with other serotonergic agents.
• Hypotension: notable drop in blood pressure post‑administration.

Palonosetron should be used with consideration of patient‑specific factors and proper handling.

• Cardiac assessment: evaluate QT interval in patients with known cardiac disease.
• Concomitant serotonergic drugs: avoid or monitor for serotonin syndrome.
• Renal impairment: adjust use in severe renal dysfunction.
• Pregnancy and lactation: use only if clearly needed; discuss risks with a healthcare professional.
• Storage: Store below 25°C: keep in the original pack, protect from moisture.

Palonosetron may interact with other medications that affect cardiac rhythm or serotonin pathways.

Major Interactions (Avoid)

• Drugs that prolong QT interval: may increase risk of cardiac arrhythmias.
• Strong CYP3A4 inhibitors: can raise palonosetron plasma levels.

Moderate Interactions (Monitor Closely)

• Serotonergic agents (e.g., SSRIs, SNRIs, triptans): monitor for serotonin syndrome.
• Anticholinergic medications: may enhance constipation risk.
• Diuretics: watch for additive blood pressure effects.
• Antihistamines: may alter perceived efficacy of anti‑emetic therapy.