Fatal poisoning with antipsychotic drugs, England and Wales 1993-2002

Abstract

Prescription of atypical antipsychotics has increased in recent years. There have also been changes in the guidance on using older drugs, particularly the restriction in the use of thioridazine. We analysed deaths due to poisoning involving antipsychotics in England and Wales, 1993-2002, by age, sex, intent, and agents involved. We also studied antipsychotic prescribing in the community and poisoning deaths in England. Deaths attributed to adverse reactions in the course of normal treatment were not studied because these deaths are not classified as ‘poisonings’. The number of deaths involving antipsychotics increased from around 55 per year 1993-1998 to 74 in 2000, and then fell to 53 in 2002. Around 25% of deaths had a verdict of accidental death and in about 60% of deaths a verdict of suicide or an open verdict was recorded. There were no deaths involving thioridazine in 2002, following its removal from use in 2001. However, the number of deaths associated with atypicals, most notably olanzapine and clozapine, has increased. Age-specific death rates were highest in those aged 30-39 and 40-49 years, and were very low in those aged under 20 and 70 or over. Death rates in males were greater than in females. For many drugs the proportion mentions either alone or with ethanol, was 25-45%, but for clozapine and olanzapine such mentions totalled 65-69%. Deaths per million prescriptions (clozapine excluded) were highest for quetiapine (31.3 per million), chlorpromazine (29.4 per million) and thioridazine (15.5 per million).