Prescribing pattern of antipsychotic drugs during the years 1996-2010: a population-based database study in Europe with a focus on torsadogenic drugs.

INTRODUCTION: Antipsychotic drugs (APDs) are used to treat several mental illnesses. Some APDs have been known since long to be associated with QT prolongation, potentially leading to Torsades de Pointes (TdP) and Sudden Cardiac Death (SCD). In 2005, thioridazine was withdrawn because of the risk of SCD, raising further attention about the arrhythmogenic potential of APDs. AIM: To evaluate the use of APDs in 5 European Countries during the years 1996-2010.

METHODS: A cohort study was conducted using prescription/dispensing data from seven healthcare databases (AARHUS [Denmark], GEPARD [Germany], Health Search/Thales (HSD) and Emilia Romagna Regional Database (ERD) [Italy], PHARMO and IPCI [Netherlands], and THIN [UK]), covering a population of 27 million individuals. The annual prescription rate of APDs was measured overall and for individual medications. APDs were classified as torsadogenic by Arizona-CERT list. All analyses were stratified by age, gender, and calendar year.

RESULTS: A total amount of 559,276 PYs of exposure to APDs was captured. The crude annual prescription rate of APD use ranged from 3.0/1,000 PYs in ERD to 7.7/1,000 PYs in AARHUS. Among APDs with established torsadogenic liability, thioridazine was the most frequently used medication in UK. Haloperidol was commonly prescribed in Italy and the Netherlands. The use of APDs with torsadogenic liability was much higher in elderly patients.

CONCLUSIONS: Substantial use of APDs with torsadogenic liability was reported in the last years in Europe, despite increasing concerns about their arrhythmogenic potential. This use was even greater in elderly patients who are at higher risk of SCD.

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