Ondansetron Stada (Ondansetron Hydrochloride Dihydrate)

Ondansetron is a selective 5‑HT3 receptor antagonist used to control nausea and vomiting associated with several therapeutic contexts.

• Chemotherapy‑induced nausea and vomiting: prevents and treats nausea and vomiting caused by cytotoxic chemotherapy.
• Radiotherapy‑induced nausea and vomiting: reduces nausea and vomiting that occur during or after radiation treatment.
• Postoperative nausea and vomiting: helps control nausea and vomiting following surgical procedures.

• Ondansetron works by selectively blocking serotonin (5‑HT3) receptors located in the chemoreceptor trigger zone and gastrointestinal tract. By inhibiting these receptors, it interrupts the neural signaling pathway that initiates the vomiting reflex, thereby reducing nausea and vomiting associated with chemotherapy, radiotherapy, and surgery.

Ondansetron is generally well tolerated, but adverse reactions can occur.

Common Side Effects

• Headache: mild to moderate headache.
• Constipation: reduced bowel movements.
• Dizziness: sensation of light‑headedness.
• Fatigue: feeling unusually tired.
• Diarrhoea: loose stools.
• Injection site pain: discomfort at the site of administration.

Serious or Rare Side Effects

• QT interval prolongation: possible cardiac arrhythmia.
• Severe allergic reaction: rash, swelling, or anaphylaxis.
• Serotonin syndrome: agitation, hyperthermia, or neuromuscular abnormalities.
• Hepatic dysfunction: elevated liver enzymes.
• Vision changes: blurred vision or visual disturbances.

When using Ondansetron, several safety considerations should be observed.

• Cardiac risk assessment: monitor QT interval in patients with known cardiac disease or electrolyte abnormalities.
• Electrolyte balance: correct hypokalaemia, hypomagnesaemia, or hypocalcaemia before administration.
• Pregnancy and lactation: evaluate risk‑benefit ratio; use only if clearly needed.
• Drug interactions: review concomitant medications that may affect cardiac conduction or serotonin levels.
• Storage conditions: Store at 2-8°C: keep refrigerated, protect from light, do not freeze or shake.

Ondansetron may interact with other medicines, altering efficacy or safety.

Major Interactions (Avoid)

• Drugs that prolong QT interval (e.g., certain antiarrhythmics, antipsychotics): increase risk of cardiac arrhythmia.
• Serotonergic agents (e.g., SSRIs, MAO inhibitors): may precipitate serotonin syndrome.

Moderate Interactions (Monitor Closely)

• CYP3A4 inhibitors (e.g., ketoconazole, erythromycin): may raise ondansetron plasma levels.
• CYP3A4 inducers (e.g., rifampicin, carbamazepine): may reduce ondansetron effectiveness.
• Apomorphine: concomitant use can cause profound hypotension.