Racemic ketamine in the treatment of resistant depressive disorder. From the research to clinical off-label aplication
Abstract
The article summarizes the findings on the efficacy and safety profile of racemic ketamine added to conventional antidepressant treatment in patients with resistant depressive disorder (TRD). Racemic ketamine (intravenous doses 0.5-1 mg/kg 40 minute infusion) has higher antidepressant and antisuicidal effect than placebo or midazolam after 24 h in patients with TRD (unipolar or bipolar).
Four or six ketamine infusions (i.v. doses 0.5-1 mg/kg 40 minute infusion) per 2 weeks has the same antidepressant effect, that was higher than placebo after 15 days. Four or six ketamine infusions per 2 weeks doubled the chance to reach response than single ketamine infusion.
The two week antidepressant and antisuicidal effect of racemic ketamine was sustained after next 4 weeks of ketamine maintence infusions. In addition to intravenous administration, intramuscular, subcutaneous, intranasal and oral applications of ketamine have been studied.
Side effects after intravenous ketamine like increase of blood pressure, pulse, dissociation, nausea and dizziness are transient and spontaneously dissapeared 1 to 2 hours after the aplication. These side effects are slighter after per os aplication.
There are no long-term placebo controlled studies lasting longer than 6 weeks. There are retrospective chart reports from the clinical practice of maintenance treatment and safety of racemic ketamine over months or years.
The racemic ketamine is not registered for the treatment of treatment resistant depression or suicidal thought and its aplication is possible only in off-label regime.