Intravenous Ketamine in the Depressed Medically Ill: A Case Series of Hospitalized Patients on the Consultation-Liaison Psychiatry Service

Abstract:

Background: While intravenous ketamine and its role in treatment-resistant depression has been increasingly studied, there is a gap in literature regarding the role of ketamine in treating acutely medically ill patients with comorbid depressive symptoms. This case series presents a novel approach of utilizing intravenous ketamine in the depressed medically ill to promote increased patient engagement in medical care as otherwise impaired by comorbid psychiatric presentation.

Method: We present a case series of four patients hospitalized within a community-based hospital in the South Bay Area for acute medical illnesses between June 2022 and January 2024. Patients who required psychiatric consultation for evaluation of mood interfering with care delivery were included. All four patients met criteria for Major Depressive Disorder (MDD) but were unable to tolerate oral antidepressants secondary to impaired GI absorption, poor oral intake, or lack of robust response. Indications for inpatient intravenous ketamine treatment were identified and after meeting inclusion criteria for novel treatment protocol, intravenous ketamine was administered at 0.5mg/kg for 3-4 sessions on average during hospital stay. Primary outcome was identified as increased patient engagement with medical care, such as participation with services such as physical/occupational therapy, and adherence with medications/nursing care. Secondary outcomes included improvement in mood as measured by MADRS, PHQ9, and GAD7.

Results: Of the four patients, three achieved 100% medication and care adherence by discharge. Psychometric data is available on two out of four patients, which found an average decrease in MADRS by 19.5 points, PHQ9 by 8 points, and GAD7 by 5.7 points. Three patients with chronic pain reported subjective improvement in pain and demonstrated reduced pain medication utilization due to ketamine treatment. One patient demonstrated mild improvement in mood during hospital stay, however continued to refuse medical care and discharged AMA with poor outpatient follow-up. One geriatric patient benefitted from treatment such that he was able to eventually be discharged on hospice home care to his family with improved mood.

Discussion: These observations suggest that inpatient ketamine treatment may be considered as a reasonable treatment for acute psychiatric stabilization for patients who otherwise would be unable to receive mental health care in an inpatient psychiatric facility given acuity of medical needs. The goal of inpatient ketamine treatment is not the complete resolution of depressive symptoms but rather the attenuation of symptom severity such that there is an improvement in motivation and engagement with the medical treatment team as physical and mental relief is rapidly provided.

Conclusion: These findings may inform future consultation-liaison practices to promote collaborative care with primary hospital services to mitigate prolonged hospital stays, improve hospital resource utilization, facilitate pain management for complex pain patients, and offer a potential adjunctive palliative treatment modality for end-of-life care.