Published: March 2012


Citalopram and Escitalopram - Similar Risk of QT Prolongation?

Information on this subject has been updated. Read the most recent information.

Prescriber Update 33(1): 3–4
March 2012

Citalopram and Escitalopram are selective serotonin reuptake inhibitors (SSRIs) used for the treatment of depressive illness.

A recent clinical study found that citalopram is associated with a dose dependent increase in the risk of QT prolongation1. QT prolongation is an established side effect of Class I and Class III antiarrhythmic medicines and a rare side effect of a wide range of other medicines that lead to cardiac dysrhythmia. For more information about drug-induced QT prolongation refer to the article published in the December 2010 edition of Prescriber Update2.

The New Zealand data sheets for citalopram have been updated to describe the risk of QT prolongation, contraindicate its use in patients with congenital long QT syndrome and recommend a new maximum dose of 40 mg daily. Information on prescribing citalopram safely has recently been published by the Best Practice Advocacy Centre (BPAC)3.

To assess if this risk extended to escitalopram, a second clinical study was conducted4. The study determined that escitalopram was associated with substantially less QT prolongation than citalopram and was only seen at supratherapeutic doses (30 mg daily). In New Zealand the recommended dose is 10 mg once daily, which can be increased to a maximum of 20 mg daily depending on the patient’s response4-6.

Although other SSRIs are available in New Zealand, the relative risk of QT prolongation associated with the use of these medicines is not yet clearly defined. Medsafe is in the process of reviewing this risk for all SSRIs and will provide further information when it is available.

Prescribers are reminded to consider the risks and benefits of SSRI treatment, particularly before prescribing in patients with congenital long QT syndrome or those with multiple risk factors.

Prescribers are advised to seek specialist cardiological and/or psychiatric advice if necessary.

Key Messages

  • Citalopram is associated with a risk of QT prolongation at therapeutic doses.
  • Escitalopram is associated with an increased risk of QT prolongation at supratherapeutic doses.
  • Citalopram and escitalopram should be used with caution in patients with multiple risk factors for QT prolongation.
  1. Food and Drug Administration. 2011. Abnormal heart rhythms associated with high doses of Celexa (citalopram hydrobromide). Drug Safety Communication, 24 August 2011
  2. Medsafe. 2010. Drug-induced QT prolongation and Torsades de Pointes – the facts. Prescriber Update, 31(4): 27-29
  3. Best Practice Advocacy Centre. 2012. Prescribing citalopram safely: an update. Best Practice Journal, 42: 38-41
  4. Healthcare Logistics. 2011. Lexapro data sheet
  5. Mylan New Zealand Ltd. 2011. Loxalate data sheet
  6. Apotex NZ Ltd. 2011. Apo-Escitalopram data sheet


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