title: Ginkgo biloba and acetazolamide prophylaxis for acute mountain sickness: a randomized, placebo-controlled trial.
abstract: BACKGROUND
  Acute mountain sickness (AMS) commonly occurs when unacclimatized individuals ascend to altitudes above 2000 m. Acetazolamide and Ginkgo biloba have both been recommended for AMS prophylaxis; however, there is conflicting evidence regarding the efficacy of Ginkgo biloba use. We performed a randomized, placebo-controlled trial of acetazolamide vs Ginkgo biloba for AMS prophylaxis.
  
  
  METHODS
  We randomized unacclimatized adults to receive acetazolamide, Ginkgo biloba, or placebo in double-blind fashion and took them to an elevation of 3800 m for 24 hours. We graded AMS symptoms using the Lake Louise Acute Mountain Sickness Scoring System (LLS) and compared the incidence of AMS (defined as LLS score > or =3 and headache).
  
  
  RESULTS
  Fifty-seven subjects completed the trial (20 received acetazolamide; 17, Ginkgo biloba, and 20, placebo). The LLS scores were significantly different between groups; the median score of the acetazolamide group was significantly lower than that of the placebo group (P=.01; effect size, 2; and 95% confidence interval [CI], 0 to 3), unlike that of the Ginkgo biloba group (P=.89; effect size, 0; and 95% CI, -2 to 2). Acute mountain sickness occurred less frequently in the acetazolamide group than in the placebo group (effect size, 30%; 95% CI, 61% to -15%), and the frequency of occurrence was similar between the Ginkgo biloba group and the placebo group (effect size, -5%; 95% CI, -37% to 28%).
  
  
  CONCLUSIONS
  In this study, prophylactic acetazolamide therapy decreased the symptoms of AMS and trended toward reducing its incidence. We found no evidence of similar efficacy for Ginkgo biloba.
authors.affiliation: Department of Emergency Medicine, Loma Linda University Medical Center and Children's Hospital, Loma Linda, CA 92354, USA. Drtkchow@aol.com
authors.forename: Tony
authors.initials: T
authors.lastname: Chow
authors.forename: Vaughn
authors.initials: V
authors.lastname: Browne
authors.forename: Heather L
authors.initials: HL
authors.lastname: Heileson
authors.forename: Desiree
authors.initials: D
authors.lastname: Wallace
authors.forename: James
authors.initials: J
authors.lastname: Anholm
authors.forename: Steven M
authors.initials: SM
authors.lastname: Green
mesh_terms: D000086:Acetazolamide / Q000627:therapeutic use*; D000328:Adult; D000532:Altitude Sickness / Q000453:epidemiology / Q000517:prevention & control*; D002257:Carbonic Anhydrase Inhibitors / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D020441:Ginkgo biloba; D006801:Humans; D008297:Male; D008875:Middle Aged; D008517:Phytotherapy; D028321:Plant Preparations / Q000627:therapeutic use*; D018709:Statistics, Nonparametric
chemical_list: D002257:Carbonic Anhydrase Inhibitors; D028321:Plant Preparations; D000086:Acetazolamide