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Ondansetron for the Treatment of Nausea Associated with Altitude Sickness

      To the Editor:
      Nausea and anorexia are common problems at high altitude. While the sedating side effect of antiemetic agents such as prochlorperazine and promethazine could be beneficial at times, there are other situations in which this effect could be quite detrimental. Ondansetron (Zofran) is a selective blocking agent of serotonin 5-HT3 receptors and has rapid onset of action. Since it lacks muscarinic and histaminic effects with receptors in the solitary tract nucleus and the chemoreceptor trigger zone (area postrema),
      it possesses neither sedating nor respiratory depressant effects. It is available as an injection, oral tablets, and oral solution, but the orally disintegrating tablets (ODT) are particularly convenient.
      I would like to report the use of ondansetron for treatment of nausea associated with acute altitude illness. One episode occurred above Berlin Camp on Aconcagua at about 7000 m in elevation. Four milligrams of ondansetron orally disintegrating tablets alone ameliorated the nausea without impeding the progress of 1 climber, a 60-year-old male with a history of acute mountain sickness who felt generally well acclimatized prior to the onset of nausea. On another occasion, 2 people, a 58-year-old male and a 51-year-old female, both novice climbers, were overcome with acute altitude-related nausea and vomiting above the Shira Plateau near the Lava Tower on Kilimanjaro at approximately 4200 m. They each received 4 mg of ondansetron (orally disintegrating tablets) in addition to 8 mg (by mouth) of dexamethasone (Decadron). They had been taking acetazolamide (Diamox) for altitude-related sleeplessness and headache. After a brief rest of approximately 30 minutes both trekkers were able to eat, rehydrate, and eventually summit. While these incidents are anecdotal, the rapidity of relief in the absence of side effects indicates that further investigation is warranted regarding the use of this medication for altitude-related nausea and vomiting.

      Reference

      1. Brunton L.L. Goodman & Gillman: The Pharmacological Basis of Therapeutics. 11th ed. Mc-Graw-Hill, New York, NY2005