Open-label pilot trial (UMIN000038347; Correia-Melo FS et al.; Federal University of Bahia / University Hospital, Salvador, Brazil; Eur Arch Psychiatry Clin Neurosci 2020, DOI 10.1007/s00406-020-01110-5). Participants: 7 adults (ages 18–65) with DSM-5 MDD, MADRS ≥25, failure to respond to ≥2 adequate antidepressant trials in current episode. No control arm, no randomisation. Intervention: single IV infusion of arketamine (R-ketamine, >99.0% enantiomeric purity, R/S ratio >99.5:0.5) at 0.5 mg/kg over 40 minutes; concomitant antidepressants continued. Primary outcome: MADRS change from baseline to 24 hours post-infusion. Results: mean MADRS dropped from 30.7 to 10.4 (mean difference 20.3 points; 95% CI 13.6–27.0; p<0.001); dissociation near-absent. Registry: UMIN (WHO ICTRP-listed Japanese registry).
Single intravenous infusion of arketamine (R-ketamine)
delivered over 40 min