Ketamine for treatment-resistant depression found to be efficacious and well tolerated.
An evaluation of ketamine for treatment-resistant depression (TRD) in clinical practice demonstrated that the intervention was efficacious and well tolerated whether patients had suicidal ideation, comorbid psychiatric conditions, or continued medication treatments.
"We believe this to be the first report of ketamine infusion treatment for treatment-resistant depression (TRD) patients participating in a clinical practice rather than prospective research," David Feifel, MD, Kadima Neuropsychiatry Institute, La Jolla, California, wrote in the published study.
Feifel and colleagues contrast their study to clinical trials that apply strict inclusion and exclusion criteria which, they indicate, "are not representative of patient selection criteria in real-word clinical practice."
They point out, for example, that most previous trials have excluded patients with comorbid psychiatric conditions other than anxiety and "severely limited" use of psychotropic medications, and that earlier trials excluded patients with suicidal ideation.
This study population consisted of 41 patients (26 male, 63.4%) receiving ketamine for TRD in an outpatient setting affiliated with an academic center. Thirty-four (82.9%) were treated for severe unipolar depression and 7 (17.1%) were treated for bipolar depression which had significantly reduced their quality of life or placed them at risk of suicide, and who had also failed to respond to medications.
Anxiety disorder was the most prevalent psychiatric comorbidity (58.5%), followed by substance-use disorder (12.2%), borderline personality disorder (9.8%), posttraumatic stress disorder (4.9%), and attention-deficit hyperactivity disorder (4.9%).
Hypertension was the most common cardiovascular comorbidity, found in 10 patients (24.4%).
Antidepressant medication was used by 21 patients (51.2%), with 5 (12.2%) taking more than 1 antidepressant concurrently. Twelve patients (29.3%) were taking an antipsychotic, 8 (19.5%) were taking a mood stabilizer, and others were taking medications ranging from stimulants to sedatives.
The investigators conducted a retrospective chart review after the patients received a single subanesthetic dose (0.5 mg/kg) of ketamine infused intravenously over 40 minutes. The primary outcome was the percentage of patients experiencing a ≥50% reduction in their Beck Depression Inventory (BDI) score from baseline after 24 hours. In addition, they assessed BDI scores at 1 hour after the infusion, and again 7 days later. Hemodynamic parameters were also monitored.
The mean baseline BDI score of 32.6 ± 8.43 (Standard Deviation) was improved by 51% to a mean of 16.0 ± 11.4 at 24 hours. Patients with bipolar depression had a comparable mean 49% reduction. Sixteen of 22 patients who were responders at 24 hours had a recorded BDI score at 7 days, and of these 12 (75%) continued to meet response criteria. Adverse effects were mild and infrequent, with 3 patients (7.3%) requiring an antiemetic while still at the infusion center.
Although the investigators acknowledge that the concurrent use of psychiatric medications complicated the assessment of ketamine efficacy and that the study was not sufficiently powered to rule out such confounders, their analysis using contingency tables did not reveal apparent differences in response or remission rates by such factors as medication use, comorbid anxiety, or gender.
"Our results generally show that a single infusion of low-dose ketamine is efficacious and generally well tolerated in the sample population treated in a 'naturalistic' clinical context," Feifel and colleagues indicated.
The evaluation of ketamine in a clinical practice setting was posted online June 17 in the Journal of Affective Disorders.