Ondansetron (Burns/Procedural Antiemetic)

How it works

It blocks serotonin 5-HT3 receptors peripherally on vagal afferents and centrally in the chemoreceptor trigger zone, interrupting the emetic reflex.

Prescribing in practice

• It prolongs the QT interval, so review the ECG and electrolytes and avoid combining with other QT-prolonging drugs, which is relevant in critically ill burns patients with electrolyte shifts.
• It is well suited to opioid- and procedure-related nausea but does not treat the mechanical or obstructive causes of vomiting, which need separate assessment.
• Constipation is a recognised effect and adds to opioid-related constipation, so anticipate bowel care in burns patients on combined therapy.

Monitoring

Monitor the QT interval and electrolytes in at-risk or critically ill patients and review antiemetic efficacy and bowel function.

Counselling the patient

• This medicine helps prevent sickness from the injury, procedures or painkillers.
• Tell staff if you feel your heart racing or skipping, or if you feel faint.
• Let the team know if you become constipated.

Evidence & guidelines

Ondansetron is a standard perioperative and procedural antiemetic; the MHRA has warned about dose-related QT prolongation.