Ondansetron Stada Stada (Ondansetron)

Ondansetron is a selective 5‑HT3 receptor antagonist used to prevent nausea and vomiting associated with several medical interventions.

• Chemotherapy‑induced nausea and vomiting: helps prevent and control nausea and vomiting in patients receiving cytotoxic chemotherapy.
• Postoperative nausea and vomiting: reduces the incidence of nausea and vomiting after surgical procedures.
• Radiotherapy‑induced nausea and vomiting: mitigates nausea and vomiting caused by radiation therapy.

• Ondansetron selectively blocks serotonin (5‑HT3) receptors located in the chemoreceptor trigger zone of the brain and on vagal afferents in the gastrointestinal tract. By inhibiting these receptors, it interrupts the signaling cascade that initiates the vomiting reflex, thereby reducing the perception of nausea and the act of vomiting.

Common Side Effects

• Headache: mild to moderate pain in the head region.
• Constipation: reduced bowel movements or hard stools.
• Diarrhoea: loose, watery stools.
• Fatigue: feeling unusually tired or weak.
• Dizziness: sensation of light‑headedness or unsteadiness.
• Abdominal pain: discomfort or cramping in the stomach area.

Serious or Rare Side Effects

• QT interval prolongation: potential cardiac arrhythmia risk.
• Severe allergic reaction: rash, swelling, or difficulty breathing.
• Serotonin syndrome: agitation, hyperthermia, and neuromuscular abnormalities when combined with other serotonergic agents.
• Hepatic dysfunction: elevated liver enzymes or jaundice.
• Neutropenia: reduced white blood cell count, increasing infection risk.
• Hypotension: sudden drop in blood pressure.

Before prescribing ondansetron, clinicians should consider patient‑specific factors and monitor for adverse events.

• Cardiac risk assessment: evaluate baseline QT interval and avoid use in patients with known prolonged QT.
• Concomitant serotonergic drugs: assess for potential serotonin syndrome when combined with other serotonergic agents.
• Hepatic impairment: adjust use in patients with severe liver disease.
• Pregnancy and lactation: weigh benefits against potential risks; use only if clearly needed.
• Store at room temperature below 25°C: keep in the original packaging, protect from moisture and light.

Ondansetron may interact with several medicines; careful review of the patient’s regimen is essential.

Major Interactions (Avoid)

• Apomorphine: concurrent use can cause severe hypotension and loss of consciousness.
• Other QT‑prolonging agents (e.g., quinidine, haloperidol): increased risk of cardiac arrhythmia.
• Potent CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may raise ondansetron plasma concentrations.

Moderate Interactions (Monitor Closely)

• Dexamethasone: may require dose adjustment due to pharmacodynamic synergy.
• Other antiemetics (e.g., metoclopramide, prochlorperazine): monitor for additive central nervous system effects.