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Clinical Trial
. 2004 Apr 3;328(7443):797.
doi: 10.1136/bmj.38043.501690.7C. Epub 2004 Mar 11.

Randomised, double blind, placebo controlled comparison of ginkgo biloba and acetazolamide for prevention of acute mountain sickness among Himalayan trekkers: the prevention of high altitude illness trial (PHAIT)

Jeffrey H Gertsch  1 , Buddha Basnyat, E William Johnson, Janet Onopa, Peter S Holck
Affiliations
Clinical Trial

Randomised, double blind, placebo controlled comparison of ginkgo biloba and acetazolamide for prevention of acute mountain sickness among Himalayan trekkers: the prevention of high altitude illness trial (PHAIT)

Jeffrey H Gertsch et al. BMJ. .

Abstract

Objective: To evaluate the efficacy of ginkgo biloba, acetazolamide, and their combination as prophylaxis against acute mountain sickness.

Design: Prospective, double blind, randomised, placebo controlled trial.

Setting: Approach to Mount Everest base camp in the Nepal Himalayas at 4280 m or 4358 m and study end point at 4928 m during October and November 2002.

Participants: 614 healthy western trekkers (487 completed the trial) assigned to receive ginkgo, acetazolamide, combined acetazolamide and ginkgo, or placebo, initially taking at least three or four doses before continued ascent.

Main outcome measures: Incidence measured by Lake Louise acute mountain sickness score > or = 3 with headache and one other symptom. Secondary outcome measures included blood oxygen content, severity of syndrome (Lake Louise scores > or = 5), incidence of headache, and severity of headache.

Results: Ginkgo was not significantly different from placebo for any outcome; however participants in the acetazolamide group showed significant levels of protection. The incidence of acute mountain sickness was 34% for placebo, 12% for acetazolamide (odds ratio 3.76, 95% confidence interval 1.91 to 7.39, number needed to treat 4), 35% for ginkgo (0.95, 0.56 to 1.62), and 14% for combined ginkgo and acetazolamide (3.04, 1.62 to 5.69). The proportion of patients with increased severity of acute mountain sickness was 18% for placebo, 3% for acetazoalmide (6.46, 2.15 to 19.40, number needed to treat 7), 18% for ginkgo (1, 0.52 to 1.90), and 7% for combined ginkgo and acetazolamide (2.95, 1.30 to 6.70).

Conclusions: When compared with placebo, ginkgo is not effective at preventing acute mountain sickness. Acetazolamide 250 mg twice daily afforded robust protection against symptoms of acute mountain sickness.

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Figures

Figure 1
Figure 1
Flow of participants through trial
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References

    1. Hackett PH, Roach RC. High altitude illness. N Engl J Med 2001;345: 107-14. - PubMed
    1. Basnyat B. Altitude sickness. In: Rakel RE, Bope ET, eds. Conn's current therapy. Philadelphia: WB Saunders, 2001: 1166-9.
    1. Roncin JP, Schwartz F, D'Arbigny P. EGb 761 in control of acute mountain sickness and vascular reactivity to cold exposure. Aviat Space Environ Med 1996;67: 445-52. - PubMed
    1. Gertsch JH, Seto TB, Mor J, Onopa J. Ginkgo biloba for the prevention of severe acute mountain sickness starting one day before rapid ascent. High Alt Med Biol 2002;2: 110. - PubMed
    1. Leadbetter GW, Maakestad K, Olson S, Hackett PH. Ginkgo biloba reduces incidence and severity of acute mountain sickness. Abstracts from the 12th international hypoxia symposium, Jasper, Alberta, Canada, March 10-14, 2001. High Alt Med Biol 2001;2: 110.

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