Is ketamine effective and safe for treatment-resistant depression?
EVIDENCE-BASED ANSWER:
MAYBE, but it’s too soon to tell. There is limited evidence that ketamine by itself is effective in the very short term. Single-dose intravenous (IV) ketamine is more likely than placebo (odds ratio = 11-13) to produce improvement (> 50%) in standardized depression scores in 1 to 3 days, lasting up to a week. Twice- or thrice-weekly IV ketamine improves symptom scores by 20%-25% over 2 weeks (strength of recommendation [SOR]: B, meta-analysis of small, low-quality, randomized controlled trials [RCTs] and a single small RCT).
Augmentation of sertraline with daily oral ketamine moderately improves symptom scores for 6 weeks in patients with moderate depression (SOR: B, small, low-quality RCTs).
Augmentation of oral antidepressants (duloxetine, escitalopram, sertraline, venlafaxine) with intranasal esketamine spray improves response and remission rates at 4 weeks (16% for both outcomes) in patients with predominantly treatment-resistant major depression (SOR: A, meta-analysis of RCTs).
Ketamine therapy is associated with confusion, emotional blunting, headache, dizziness, and blurred vision (SOR: A, meta-analyses).
Nasal esketamine spray produces the adverse effects of dizziness, vertigo, and blurred vision severe enough to cause discontinuation in 4% of patients; it also can produce transient elevation of blood pressure (SOR: A, meta-analyses).
Nasal esketamine produced more AEs causing discontinuation than did placebo (5.8% vs 1.5%; RR = 3.5; 95% CI, 1.34-8.9; number needed to harm [NNH] = 23), including blurred vision, dizziness, sedation, nausea, and dysphoria.5A review (5 RCTs and 1 open-label trial; N = 1708) analyzing the cardiac safety profile of intranasal esketamine adjuvant therapy found that it produced transient and asymptomatic blood pressure elevations (OR = 3.2; 95% CI, 1.9-5.8; NNH = 13).7
Recommendations from others
A clinical practice guideline from the US Veterans Administration lists IV ketamine as 1 of the therapeutic options for patients with treatment-resistant depression and suicidal ideation.8 However, a Department of Veterans Affairs Panel restricted its use to a pre-approved case-by-case basis.8
Editor’s takeaway
Physicians with patients facing the all-too-common problem of treatment-resistant major depression will be wondering if ketamine, either by itself or as an augmentation therapy, can help. Unfortunately, the outcomes we report here are too short term to answer that question, and we must await the results of further studies. Augmentation with intranasal esketamine, at a cost of $370/month, might offer some promise.
