Ondansetron Syrup

Ondansetron Syrup – Full Introduction

Ondansetron syrup is an antiemetic medication used to prevent and treat nausea and vomiting in both children and adults. It is especially effective in vomiting associated with gastroenteritis, chemotherapy, radiotherapy, and postoperative states. The syrup formulation is commonly used in pediatric patients for ease of dosing.

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Drug Class

• Antiemetic

• Selective 5-HT₃ (serotonin) receptor antagonist

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Mechanism of Action

Ondansetron works by blocking 5-HT₃ receptors located:

• Peripherally on vagal nerve terminals in the gastrointestinal tract

• Centrally in the chemoreceptor trigger zone (CTZ) of the brain

By blocking serotonin-mediated stimulation, ondansetron effectively prevents the vomiting reflex.

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Therapeutic Uses

• Acute gastroenteritis–related nausea and vomiting

• Chemotherapy-induced nausea and vomiting (CINV)

• Radiation-induced nausea and vomiting

• Postoperative nausea and vomiting

• Vomiting due to acute illness in children

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Benefits

• Highly effective antiemetic

• Non-sedating (unlike older antiemetics)

• Safe and well tolerated in children

• Rapid onset of action

• Does not affect gastric motility significantly

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Common Side Effects

• Headache

• Constipation

• Dizziness

• Fatigue

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Serious but Rare Side Effects

• QT interval prolongation (risk of arrhythmias)

• Hypersensitivity reactions

• Serotonin syndrome (rare, when combined with serotonergic drugs)

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Contraindications & Precautions

• Known hypersensitivity to ondansetron

• Congenital long QT syndrome

• Use with caution in:

  • Electrolyte imbalance (hypokalemia, hypomagnesemia)

  • Cardiac disorders

  • Concomitant use of QT-prolonging drugs

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Dosage & Administration

• Children: Dose based on body weight (commonly 0.15 mg/kg per dose)

• Adults: As prescribed

• Common syrup strength: 4 mg/5 mL

• Can be given with or without food

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Conclusion

Ondansetron syrup is a safe, effective, and widely used antiemetic, especially in children with vomiting. When used at recommended doses, it provides excellent control of nausea and vomiting with minimal side effects. Caution is advised in patients with cardiac conditions.