A single intravenous infusion of arketamine (0.5 mg/kg) rapidly reduced depression severity in seven people with treatment-resistant depression. The Montgomery–Åsberg Depression Rating Scale score fell from an average of 30.7 before infusion to 10.4 after one day, a mean drop of 20.3 points. Dissociative side effects were nearly absent. The findings suggest arketamine may produce fast-onset and sustained antidepressant effects with a favorable safety profile, as previously observed in animals, but controlled trials are needed to confirm.
In adults with treatment-resistant depression, a single intravenous infusion of esketamine (0.25 mg/kg) was non-inferior to ketamine (0.5 mg/kg) for achieving remission 24 hours later. Among 63 participants, 29.4% in the esketamine group and 24.1% in the ketamine group showed remission, a difference of 5.3% that fell within the predefined non-inferiority margin. Depression scores on the Montgomery-Åsberg Depression Rating Scale improved similarly in both groups, and side effects were mild and comparable. The findings suggest that esketamine at half the dose of ketamine offers equivalent short-term efficacy and safety.