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Aetiology and risk factors

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

In individual cases of torsades de pointes there are often multiple risk factors present (1,2):

  • electrolyte disturbances (in particular, hypokalaemia, hypomagnesaemia and more rarely hypocalcaemia). Consider the risk of electrolyte disturbance if the patient has gastrointestinal upset
  • bradycardia
  • concomitant use of more than one drug that may prolong the QT interval for example (and not an exhaustive list) (1,2):
    • procainamide
    • quinidine
    • citalopram
    • ondansetron
    • quinine
    • amiodarone
    • methadone
  • Congenital long QT syndrome.
  • cardiac disease (of multiple origins, including congestive heart failure, ventricular hypertrophy, myocardial infarction, recent conversion from atrial fibrillation).
  • impaired hepatic/renal function (due to effects on drug metabolism/excretion).
  • thyroid disease (more common with hypothyroidism and usually normalises with treatment)
  • female sex.
  • age over 65 years
  • hypothermia


  1. Current Problems in Pharmacovigilance (2006);31:1-12.
  2. NHS Specialist Pharmacy Service (January 2020). What issues should be considered regarding drug-induced QT prolongation?

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