Rationale
Depressed patients presenting to emergency departments with acute suicidal ideation are a major public health concern. Ketamine, a rapidly acting antidepressant with antisuicidal properties, might offer relief.

Objective
Evaluation of single, fixed-dosed intranasal ketamine for acute suicidal ideation in the emergency department.

Methods
In a randomized, double-blind, placebo-controlled, proof-of-concept trial, 18 depressed subjects with acute suicidal ideation, who required hospitalization, were randomized to either an intravenous ketamine 0.2 mg/kg group or a saline placebo group. Safety and efficacy evaluations were scheduled for 15, 30, 60, 90, 120, 180, and 240 min, and on Days 1, 2, 3, 7, and 14 after infusion. The main outcome measure was suicidal ideation with secondary measures of depression.
Results
Nine subjects were randomized to each group. There were no differences between groups at baseline in any demographic or assessment scales. A reduction in suicidal ideation was noted at 90-180 min (p < .05). Ninety minutes after infusion, 88% of the ketamine group had achieved remission of suicidal ideation compared with 33% in the placebo group (p < .05). No serious adverse events were noted. Conclusion Ketamine was safe and effective for rapid reduction in suicidal ideation in depressed, highly suicidal subjects presenting to the emergency department. Our results support further study of ketamine for acute suicidal ideation.