title: Intravenous ketamine for subacute treatment of refractory chronic migraine: a case series.
abstract: BACKGROUND
  Refractory migraine is a challenging condition with great impact on health related quality of life. Intravenous (IV) ketamine has been previously used to treat various refractory pain conditions. We present a series of patients with refractory migraine treated with intravenous ketamine in the hospital setting.
  
  
  METHODS
  Based on retrospective chart review, we identified six patients with refractory migraine admitted from 2010 through 2014 for treatment with intravenous ketamine. Ketamine was administered using a standard protocol starting with a dose of 0.1 mg/kg/hr and increased by 0.1 mg/kg/hr every 3 to 4 h as tolerated until the target pain score of 3/10 was achieved and maintained for at least 8 h. Visual Analogue Scale (VAS) scores at time of hospital admission were obtained as well as average baseline VAS scores prior to ketamine infusion. A phone interview was conducted for follow-up of migraine response in the 3 to 6 months following ketamine infusion.
  
  
  RESULTS
  The study sample had a median age of 36.5 years (range 29-54) and 83% were women. Pre-treatment pain scores ranged from 9 to 10. All patients achieved a target pain level of 3 or less for 8 h; the average ketamine infusion rate at target was 0.34 mg/kg/hour (range 0.12-0.42 mg/kg/hr). One patient reported a transient out-of-body hallucination following an increase in the infusion rate, which resolved after decreasing the rate. There were no other significant side effects.
  
  
  CONCLUSIONS
  IV ketamine was safely administered in the hospital setting to patients with refractory chronic migraine. Treatment was associated with short term improvement in pain severity in 6 of 6 patients with refractory chronic migraine. Prospective placebo-controlled trials are needed to assess short term and long-term efficacy of IV ketamine in refractory chronic migraine.
authors.affiliation: Department of Neurology, Thomas Jefferson University, Jefferson Headache Center, Philadelphia, PA, USA. Clinton.Lauritsen@jefferson.edu.
authors.forename: Clinton
authors.identifier: http://orcid.org/0000-0003-3225-4446
authors.initials: C
authors.lastname: Lauritsen
authors.affiliation: Department of Neurology, Thomas Jefferson University, Jefferson Headache Center, Philadelphia, PA, USA.
authors.forename: Santiago
authors.initials: S
authors.lastname: Mazuera
authors.affiliation: Department of Neurology, Montefiore Headache Center, Albert Einstein College of Medicine, Bronx, NY, USA.
authors.forename: Richard B
authors.initials: RB
authors.lastname: Lipton
authors.affiliation: Department of Neurology, New York University School of Medicine, NYU Langone Medical Center, NYU Lutheran Headache Center, New York, NY, USA.
authors.forename: Sait
authors.initials: S
authors.lastname: Ashina
mesh_terms: D000328:Adult; D002908:Chronic Disease; D018691:Excitatory Amino Acid Antagonists / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007649:Ketamine / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000188:drug therapy*; D010147:Pain Measurement; D010148:Intractable Pain / Q000188:drug therapy*; D011788:Quality of Life; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D018691:Excitatory Amino Acid Antagonists; D007649:Ketamine