Cardiac arrest and ventricular arrhythmia in patients taking antipsychotic drugs: cohort study using administrative data.
OBJECTIVE
To examine the rates of cardiac arrest and ventricular arrhythmia in patients with treated schizophrenia and in non-schizophrenic controls.


METHODS
Cohort study of outpatients using administrative data.


METHODS
3 US Medicaid programmes.


METHODS
Patients with schizophrenia treated with clozapine, haloperidol, risperidone, or thioridazine; a control group of patients with glaucoma; and a control group of patients with psoriasis.


METHODS
Diagnosis of cardiac arrest or ventricular arrhythmia.


RESULTS
Patients with treated schizophrenia had higher rates of cardiac arrest and ventricular arrhythmia than controls, with rate ratios ranging from 1.7 to 3.2. Overall, thioridazine was not associated with an increased risk compared with haloperidol (rate ratio 0.9, 95% confidence interval 0.7 to 1.2). However, thioridazine showed an increased risk of events at doses > or =600 mg (2.6, 1.0 to 6.6; P=0.049) and a linear dose-response relation (P=0.038).


CONCLUSIONS
The increased risk of cardiac arrest and ventricular arrhythmia in patients with treated schizophrenia could be due to the disease or its treatment. Overall, the risk with thioridazine was no worse than that with haloperidol. Thioridazine may, however, have a higher risk at high doses, although this finding could be due to chance. To reduce cardiac risk, thioridazine should be prescribed at the lowest dose needed to obtain an optimal therapeutic effect.
Hennessy
Sean
S
Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA. shenness@cceb.med.upenn.edu
Bilker
Warren B
WB
Knauss
Jill S
JS
Margolis
David J
DJ
Kimmel
Stephen E
SE
Reynolds
Robert F
RF
Glasser
Dale B
DB
Morrison
Mary F
MF
Strom
Brian L
BL
D000328:Adult; D000368:Aged; D014150:Antipsychotic Agents / Q000009:adverse effects*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced*; D003024:Clozapine / Q000009:adverse effects; D015331:Cohort Studies; D016001:Confidence Intervals; D016757:Death, Sudden, Cardiac / Q000209:etiology; D005260:Female; D006220:Haloperidol / Q000009:adverse effects; D006323:Heart Arrest / Q000139:chemically induced*; D006801:Humans; D008297:Male; D008484:Medicaid / Q000706:statistics & numerical data; D008875:Middle Aged; D018967:Risperidone / Q000009:adverse effects; D012559:Schizophrenia / Q000188:drug therapy*; D013881:Thioridazine / Q000009:adverse effects; D014481:United States
D014150:Antipsychotic Agents; D003024:Clozapine; D006220:Haloperidol; D018967:Risperidone; D013881:Thioridazine