SAQ 153 – Toxicology – prolonged QT in overdose

Question 5. prolonged QT in overdose.

a. Major abnormality

• Prolonged QT.

b. Drugs

• Antiarrhythmics such as quinidine, procainamide, disopyramide, sotalol, or amiodarone.
• Macrolides such as erythromycin.
• Antihistamines such as diphenhydramine, loratadine, astemizole, or terfenadine.
• Organophosphates.
• Antipsychotics such as chlorpromazine, droperidol, haloperidol, thioridazine, quetiapine, olanzapine, or amisulpride.
• Tricyclic antidepressants such as amitriptyline, doxepin, imipramine, or nortriptyline.
• Other antidepressants such as citalopram, escitalopram, venlafaxine, bupropion, moclobemide, or mianserin.
• Chloroquine, hydroxychloroquine, or quinine.

c. Non-medication causes

• Congenital long QT syndromes such as Romano-Ward or Jervell-Lange-Nielsen.
• Hypokalaemia.
• Hypocalcaemia.
• Hypomagnesaemia.
• IHD / AMI, LVF, bradycardia, or complete heart block.
• Acute rheumatic carditis, mitral valve prolapse, or myocarditis.
• Stroke or intracranial haemorrhage, especially SAH.
• Hypothermia.
• Extreme bradycardia from any cause.