A case series of inpatient ketamine infusion for treatment-resistant depression in Taiwan

Treatment-resistant depression (TRD) represents a major clinical challenge, particularly in patients requiring psychiatric hospitalization. Intravenous ketamine has demonstrated rapid antidepressant effects; however, its real-world application in acute inpatient psychiatric settings remains limited and insufficiently described. Ketamine remains an off-label and regulated substance in many jurisdictions, posing a clinical dilemma between the urgent need for rapid symptom relief and concerns regarding safety, misuse, and institutional governance. We report a case series of four inpatients with TRD who received low-dose intravenous ketamine infusion as part of routine clinical care in a Taiwanese medical center. The clinical context, treatment course, and short-term outcomes are described, with particular attention to inpatient-specific considerations such as safety monitoring, ethical approval, and concerns regarding misuse. Short-term reductions in depressive symptoms were observed within hours of infusion, with adverse effects that were transient under inpatient monitoring. This case series highlights practical clinical considerations relevant to inpatient ketamine use and underscores the need for further systematic investigation of its role in real-world psychiatric care.