Reckless administration of QT interval-prolonging agents in elderly patients with drug-induced torsade de pointes.

Abstract

Asystematic review was conducted for all published case reports on drug-induced torsade de pointes (TdP) in elderly (≥80years) patients to study if the administration of the offending agent was reckless. Overall, 61reports on drug-induced TdP in patients aged 80-97years were included in the analysis. Non-modifiable risk factors for drug-induced TdP (e.g. acute coronary syndrome, female gender and congestive heart failure), modifiable risk factors (e.g. hypokalemia, severe hypomagnesemia and digitalis toxicity) and reckless administration of aQT interval-prolonging agent (e.g. despite aknown QT interval prolongation or ahistory of TdP, together with other QT interval prolonging agents in higher than recommended doses) were recorded in each case. Overall, 54(88.5%) patients had non-modifiable risk factors for drug-induced TdP and 21(34.4%) patients had modifiable risk factors. The administration of the offending agent was reckless in one half (n= 31; 50.8%) of the patients. The most prevalent reckless administration of aQT interval-prolonging agent was together with other QT interval-prolonging agents (n= 16; 51.6%) or despite QT interval prolongation (n= 8; 25.8%). In conclusion, although risk factors for drug-induced TdP are prevalent in elderly patients with drug-induced TdP, in approximately 50% of patients it appeared following areckless administration of aQT interval-prolonging agent. In this population physicians should particularly avoid administration of two or more QT interval-prolonging agents simultaneously or administration of aQT interval-prolonging agent despite QT interval prolongation.