title: Repeated intravenous ketamine therapy in a patient with treatment-resistant major depression.
abstract: BACKGROUND
  The intravenous administration of ketamine, an N-methyl-D-aspartate receptor antagonist, results in a great improvement of depression symptoms, but it is not clear for how long. This single-case trial was conducted to explore the duration of improvement and the effects of a second administration on the clinical outcome.
  
  
  METHODS
  In an open label trial, a 55-year-old male patient with treatment-resistant major depression and a co-occurring alcohol and benzodiazepine dependence received two intravenous infusions of 0.5 mg/kg ketamine over the course of 6 weeks. Depression severity was assessed by means of a weekly clinical interview, the 21-item Hamilton Depression Rating Scale (HDRS), and the 21-item Beck Depression Inventory (BDI).
  
  
  RESULTS
  The first ketamine infusion lead to a pronounced improvement of symptoms, peaking on the second day post infusion (HDRS -56.6%, BDI -65.4%). Positive effects started fading by day 7, reaching baseline by day 35. The second infusion was less efficacious: HDRS and BDI were reduced by 43 and 35%, respectively, and returned to baseline by day 7.
  
  
  CONCLUSIONS
  In this patient with a co-occurring substance use disorder, repeated administrations of ketamine produced positive results. Since the second application has been less efficacious, doses and schedule of administrations need to be further investigated.
authors.affiliation: Psychiatric University Hospital, Research Group on Substance Use Disorders, Zurich, Switzerland. Michael.Liebrenz@puk.zh.ch
authors.forename: Michael
authors.initials: M
authors.lastname: Liebrenz
authors.forename: Rudolf
authors.initials: R
authors.lastname: Stohler
authors.forename: Alain
authors.initials: A
authors.lastname: Borgeat
mesh_terms: D000778:Anesthetics, Dissociative / Q000008:administration & dosage*; D000928:Antidepressive Agents / Q000009:adverse effects / Q000627:therapeutic use; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology; D004334:Drug Administration Schedule; D004351:Drug Resistance; D004359:Drug Therapy, Combination; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage*; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010555:Personality Inventory / Q000706:statistics & numerical data; D011594:Psychometrics; D012008:Recurrence; D019233:Retreatment
chemical_list: D000778:Anesthetics, Dissociative; D000928:Antidepressive Agents; D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine