Aripiprazole overdose in Hong Kong: A 10‐year retrospective cohort

Abstract Introduction Aripiprazole is considered to have a favourable safety profile in overdose, with low risks of cardiovascular and neurological toxicity. However, local data are limited, and the impact of co‐ingestants remains insufficiently studied. Methods This was a retrospective cohort of aripiprazole overdose cases reported to the Hong Kong Poison Information Centre between 2014 and 2023. Cases were stratified into single‐drug and mixed‐drug exposure groups. The primary outcome was to compare the toxicity profile between the groups; secondary outcomes included evaluating the relationship of aripiprazole ingested dose and clinical presentation and the effect of different co‐ingestants. Results Of the 211 cases included, 44 were single‐drug and 167 were mixed‐drug overdoses. In single‐drug group, 75% developed clinical features, most commonly tachycardia (39%), dizziness (36%), and nausea/vomiting (18%); seizures (2.3%) and dystonia (4.5%) were rare. QRS widening (14%) and QTc prolongation (36%) were observed. Mixed‐drug group had more frequent clinical features (87% vs 75%, p  = 0.041) with diverse co‐ingestion patterns (48% involving ≥3 substances). No dose‐dependent toxicity was observed in single‐drug cases up to 450 mg of aripiprazole. Adverse outcome (defined as inotrope use, mechanical ventilation, or intensive care unit admission) occurred exclusively in mixed‐drug group (17%, p  = 0.003), and was associated with antihypertensives (RR 2.99, 95% CI: 1.37–6.52) especially beta‐blockers (RR 2.63, 95%: 1.31–5.27; p  = 0.019) and antidiabetic agents ( p  = 0.029). No mortality was recorded. Conclusion Isolated aripiprazole overdose showed a benign clinical course, although neurological features and ECG abnormalities could occur. Mixed‐drug ingestions were associated with greater toxicity. Clinicians should actively examine for co‐ingestants when presentation is inconsistent.