NHS Greater Glasgow & Clyde Area Drug and Therapeutics Committee
Greater Glasgow and Clyde Medicines
Medicines Update

Hydroxyzine and heart rhythm abnormalities

The MHRA have updated prescribing advice for this antihistamine following concerns of heart rhythm abnormalities. A European review concluded that hydroxyzine is associated with a small risk of QT interval prolongation and Torsade de Pointes. Such events are most likely to occur in patients who already have risk factors for QT prolongation.


The recent Medicines Update Extra bulletin on drug induced QT prolongation has been revised to take account of this new information.


The main advice recommends that when using hydroxyzine:

  • do not prescribe hydroxyzine to people with a prolonged QT interval or who have risk factors for QT interval prolongation
  • avoid use in the elderly - they are more susceptible than younger patients to the side effects of hydroxyzine
  • consider the risks of QT interval prolongation and Torsade de Pointes before prescribing to patients taking medicines that lower heart rate, lower potassium levels or are known to prolong the QT interval

The maximum daily dose is now

  • 100mg for adults
  • 50mg for the elderly (if use cannot be avoided)
  • 2mg / kg body weight for children up to 40 kg in weight
  • prescribe the lowest effective dose for as short a time as possible


Continue to report any suspected side effects to hydroxyzine or any other medicine on a Yellow Card