Parenteral clomipramine in inpatient depression: a retrospective cohort study of treatment patterns and patient characteristics.

BACKGROUND: Parenteral clomipramine (PARCL) is used as a rapidly acting antidepressant in inpatients with severe depression and is sometimes positioned as an alternative to electroconvulsive therapy (ECT), despite limited comparative data. OBJECTIVES: To describe real-world PARCL use at a large university hospital, including patient characteristics, treatment patterns, discontinuation and side effect rates, and circumstances under which PARCL was documented in patient records as an alternative to ECT. METHODS: We conducted a retrospective cohort study using electronic medical records at Sahlgrenska University Hospital, Sweden, 2016-2023. Eligible admissions included patients with depression, aged 18-65 years, with a hospital stay of ≥7 days; admissions involving bipolar disorder, non-affective psychotic disorder, withdrawal syndromes, dementia, or brain injury were excluded. RESULTS: Of 11,250 admissions with depression, 5953 met the inclusion criteria, and 242 admissions (204 unique patients) received PARCL (utilization 4.1%), compared with 10.3% for ECT and 0.8% for newly initiated oral clomipramine. PARCL was used in a clinically severe population, with active suicidal ideation or recent suicide attempt in 63.7% of admissions. Treatment was generally well tolerated; 11.9% of admissions discontinued, mainly due to adverse events (7.0%). In 45.5% of PARCL admissions, treatment was recorded as an alternative to ECT, mainly selected because of patient preference or prior negative ECT outcomes. CONCLUSIONS: PARCL was mainly used for severe depression and was frequently positioned as an alternative to ECT. Prospective controlled studies are needed to clarify its comparative effectiveness, safety, and role in inpatient depression management in general hospital psychiatry.