Ondansetron IV dose restriction

The maximum dose of intravenous ondansetron has been restricted to reduce the risk of QT prolongation.

Ondansetron should be avoided in patients with congenital long QT syndrome | SCIENCE PHOTO LIBRARY
Ondansetron should be avoided in patients with congenital long QT syndrome | SCIENCE PHOTO LIBRARY

For the management of chemotherapy-induced nausea and vomiting in adults, the new maximum single intravenous dose of ondansetron is 16mg infused over a minimum period of 15 minutes.

The results of a new study identified a dose-dependent prolongation of the electrocardiographic-corrected QT interval (QTc) in adults receiving intravenous ondansetron. QTc prolongation can lead to torsades de pointes, a potentially life-threatening cardiac arrhythmia.

Use with caution

Ondansetron should avoided in patient with congenital long QT syndrome and caution must be used in patients with risk factors for QT prolongation or cardiac arrhythmias. These include:

  • electrolyte abnormalities;
  • congestive heart failure;
  • bradyarrhythmias;
  • use of other medicines that prolong the QT interval (including cytotoxic drugs) or cause electrolyte abnormalities;
  • use of medicines that lower the heart rate.

Hypokalaemia and hypomagnesaemia should be corrected before administration of ondansetron.

View ondansetron drug records

View MHRA safety warning

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