In adults with treatment-resistant depression, intranasal esketamine at doses of 28 mg, 56 mg, and 84 mg produced a rapid, dose-related reduction in depressive symptoms compared to placebo, as measured by the Montgomery-Åsberg Depression Rating Scale. The improvement appeared to persist for more than two months even when dosing frequency was reduced. Adverse events leading to discontinuation occurred in 5% of esketamine-treated participants during the double-blind phase and in 2% during the open-label phase, with no such events in the placebo group.
A single 40-minute intravenous infusion of esketamine at either 0.20 mg/kg or 0.40 mg/kg produced a rapid and robust antidepressant effect in patients with treatment-resistant depression, with significant improvement in depression scores within two hours. The higher and lower doses were similarly effective, but the lower dose may offer better tolerability. Common side effects included headache, nausea, and transient dissociation that resolved within four hours.