D-cycloserine for Relapse Prevention Following Intravenous Ketamine in Treatment-resistant Depression

This study first administers six IV sub-anesthetic ketamine infusions (0.5 mg/kg over 40 minutes) over three weeks; responders (≥25% MADRS reduction) enter a randomised, triple-blind, placebo-controlled maintenance phase.

Responders are randomised to oral D-cycloserine or matched placebo, titrated 250→500→750→1000 mg/day and continued for eight weeks to evaluate relapse prevention; outcomes include MADRS, CGI, safety and vitals.