Characteristics and toxicology of adult deaths due to quetiapine toxicity in Australia, 2000-2024.

Quetiapine is an atypical antipsychotic that has been associated with both intentional and unintentional deaths. We aimed to determine, stratified by intentionality: (1) The characteristics and circumstances of adult deaths attributed solely to quetiapine toxicity in Australia, 2000-2024; (2) The blood toxicology of cases for quetiapine and other drugs; and (3) The major autopsy findings for cardiovascular, lung, kidney, and liver disease. All cases of death aged ≥15 years attributed solely to quetiapine toxicity in Australia, 2000-2024, were retrieved from the National Coronial Information System. We identified 136 adult cases attributed solely to quetiapine toxicity. In 64.7% (n = 88), the fatal poisoning was deemed intentional, unintentional in 19.9% (n = 27), and of undetermined intent in 15.4% (n = 21). The mean age was 42.4 years (range 15-69) and 58.1% (n = 79) were male. A history of mental health problems was documented in 92.6% (n = 126). The median quetiapine concentration was 12.0 mg/L (range 1.2-600.0), with that of intentional cases being twice that of unintentional cases (13.0 vs. 6.3 mg/L). Other psychotropic drugs not considered contributory to death were present in 73.0% (n = 92) of cases, most commonly hypnosedatives (34.1%, n = 43) and antidepressants (33.3%, n = 42). Hearts were examined in 87 cases, of which 31.0% (n = 27) were diagnosed with cardiovascular disease. Given these findings, screening patients prescribed quetiapine for suicide histories and ideation is prudent, as is monitoring cardiovascular disease. For forensic pathologists, the extent and nature of cardiovascular disease appear important for the formulation of death, and suicide should be borne in mind.