Ondansetron Teva (Ondansetron)

Ondansetron Teva is a 5‑HT3 receptor antagonist used to control nausea and vomiting across several clinical pathways.

• Chemotherapy‑induced nausea and vomiting: reduces frequency and severity of episodes in cancer patients.
• Radiation‑induced nausea and vomiting: provides relief during and after radiotherapy.
• Postoperative nausea and vomiting: helps prevent and treat nausea after surgical procedures.

• Ondansetron selectively blocks serotonin (5‑HT3) receptors located in the chemoreceptor trigger zone and gastrointestinal tract. By inhibiting these receptors, it prevents serotonin‑mediated stimulation of the vomiting centre in the brain, thereby reducing the initiation of nausea and emesis caused by chemotherapy, radiation, or surgical stress.

Common Side Effects

• Headache: mild to moderate intensity.
• Constipation: reduced bowel movements.
• Diarrhoea: loose stools.
• Dizziness: sensation of light‑headedness.
• Fatigue: feeling unusually tired.
• Abdominal pain: discomfort in the stomach area.

Serious or Rare Side Effects

• QT prolongation: potential cardiac rhythm disturbance.
• Anaphylaxis: severe allergic reaction requiring immediate medical attention.
• Serotonin syndrome: rare but life‑threatening condition when combined with other serotonergic agents.
• Cardiac arrhythmia: irregular heartbeats beyond QT changes.
• Severe skin reactions: such as Stevens‑Johnson syndrome or toxic epidermal necrolysis.

Before initiating therapy, consider the following precautions:

• Cardiac risk assessment: obtain ECG in patients with known QT prolongation or cardiac disease.
• Concomitant QT‑prolonging drugs: avoid or monitor use with other agents that affect cardiac repolarisation.
• Hepatic impairment: use caution and consider dose adjustment in severe liver dysfunction.
• Electrolyte balance: correct hypokalaemia or hypomagnesaemia to reduce cardiac risk.
• Store at room temperature: keep in the original container, protect from moisture and light.

Ondansetron may interact with several medicines; awareness of the interaction level guides clinical decisions.

Major Interactions (Avoid)

• Apomorphine: co‑administration can cause severe hypotension.
• Other QT‑prolonging agents (e.g., quinidine, erythromycin): increase risk of cardiac arrhythmia.
• Carbamazepine: induces metabolism, reducing ondansetron efficacy.
• Ritonavir: inhibits metabolism, raising ondansetron plasma levels.
• Aprepitant: may enhance QT prolongation risk.

Moderate Interactions (Monitor Closely)

• SSRIs and other serotonergic drugs: elevate risk of serotonin syndrome.
• Anticholinergics: may diminish antiemetic effect.
• Opioids: can mask nausea, complicating assessment of therapeutic response.