Acetaminophen: a viable alternative for preventing acute mountain sickness

Available without prescription and with fewer side effects than acetazolamide and ibuprofen, acetaminophen is effective, according to the latest issue of Wilderness & Environmental Medicine


Philadelphia, PA June 19, 2017

Trekking and mountain climbing are quickly growing in popularity, but.one of the challenges that climbers face is acute mountain sickness (AMS). Previous studies have shown that ibuprofen is an effective way to reduce the risk of AMS. Investigators wanted to find out if acetaminophen, a commonly used anti-pain medicine like ibuprofen, would have a comparable effect. They found almost no difference in the performance of both drugs, suggesting that acetaminophen may be another effective prophylactic treatment for AMS. Their results are published in Wilderness & Environmental Medicine.

AMS occurs when the body does not properly acclimatize to increasing elevation. The gold standard of prophylactic medication for AMS is acetazolamide, a prescription medication with distressing side effects like tingling and burning sensation (paresthesia), especially in the fingers and toes, and the risk of an allergic reaction. While ibuprofen had been shown to reduce the risk of AMS, it may have common unwanted side effects. Therefore, investigators wanted to assess whether acetaminophen, a popular and readily available drug similar in action to ibuprofen with fewer gastrointestinal side effects might also reduce the risk of AMS.

“The results of this study found no significant difference in the incidence and severity of AMS between prophylactic dosing of acetaminophen and ibuprofen,” noted the study’s lead investigator Buddha Basnyat, MD, from the Oxford University Clinical Research Unit, Kathmandu, Nepal, and the Himalayan Rescue Association and the Centre for Tropical Medicine and Global Health, University of Oxford, UK, and his co-investigators. “These results suggest that acetaminophen performs similar to ibuprofen in the prevention of AMS in partially-acclimatized subjects.”

AMS is potentially deadly. The condition can often start out with symptoms normally associated with altitude sickness: headache, dizziness, fatigue, upset stomach, and poor sleep. If left untreated, AMS can progress and cause fatal neurologic or pulmonary conditions. “The best prevention of altitude illness is a slow ascent,” explained Dr. Basnyat and his co-investigators. “However, proper acclimatization might be ignored or deemed impractical by mountain climbers, hikers, local pilgrims, rescue teams, or military operations.”

A double-blind randomized trial followed 332 non-Nepali participants along the Everest trekking route. Subjects were recruited in both Pheriche (4371 m elevation) and Dingboche (4410 m) and instructed to take either acetaminophen or ibuprofen three times a day until they reached Lobuche (4940 m) where they were assessed using the Lake Louise Questionnaire, a well-established tool, to determine whether or not they had AMS. While some of the climbers did present with AMS at Lobuche, investigators found no statistically significant difference in the incidence and severity of AMS between the two groups.

Trekkers on the way to Everest Base Camp. Credit: Buddha Basnyat

“This finding suggests that the pathophysiology of AMS may not only be dependent on arachidonic-acid pathway and inflammation triggered by ibuprofen, but also other mechanisms that mediate nociception influenced by acetaminophen,” concluded Dr. Basnyat and his co-investigators. “More studies need to be done, but this study clearly shows acetaminophen may be effective in the prevention of AMS and could be potentially useful for people who want an alternative drug to acetazolamide for the prevention of AMS.”

"We appreciate the efforts of these investigators to evaluate questions that can impact the health and safety of many who journey into the high-altitude realm," stated Neal Pollock, PhD, editor-in-chief of Wilderness & Environmental Medicine, "and we are pleased to share the results with the community through the journal."

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Notes for editors
The article is “Prophylactic Acetaminophen or Ibuprofen Result in Equivalent Acute Mountain Sickness Incidence at High Altitude: A Prospective Randomized Trial,” by Nicholas C. Kanaan, MD; Alicia L. Peterson, MD; Matiram Pun, MD; Peter S. Holck, PhD; Jennifer Starling, MD; Bikash Basyal, MD; Thomas F. Freeman, MD; Jessica R. Gehner, MD; Linda Keyes, MD; Dana R. Levin, MD; Catherine J. O’Leary, MD; Katherine E. Stuart, MD; Ghan B. Thapa, MD; Aditya Tiwari, MD; Jared L. Velgersdyk, MD; Ken Zafren, MD; and Buddha Basnyat, MD (https://doi.org/10.1016/j.wem.2016.12.011). It appears in Wilderness & Environmental Medicine, volume 28, issue 2 (June 2017) published by Elsevier.

Full text of this article is available to credentialed journalists upon request. Contact Theresa Monturano at +1 215-239-3711 or hmsmedia@elsevier.com to obtain copies. Journalists wishing to interview the authors should contact Buddha Basnyat, MD, at buddhabasnyat@gmail.com.

About Wilderness & Environmental Medicine
Wilderness & Environmental Medicine (WEM), the official journal of the Wilderness Medical Society, is a peer-reviewed international journal for physicians practicing medicine in austere environments. It is devoted to original scientific and technical contributions on the practice of medicine defined by isolation, extreme natural environments, and limited access to medical help and equipment. Examples of topics covered include high altitude and climbing; hypothermia and cold-induced injuries; drowning and near-drowning; hazardous plants, reptiles, insects, and marine animals; animal attacks; search and rescue. www.wemjournal.org

About the Wilderness Medical Society
Founded in 1983, the Wilderness Medical Society (WMS) is the world's leading organization devoted to wilderness medical challenges. Wilderness medicine topics include expedition and disaster medicine, dive medicine, search and rescue, altitude illness, cold- and heat-related illness, wilderness trauma, and wild animal attacks. WMS explores health risks and safety issues in extreme situations such as mountains, jungles, deserts, caves, marine environments, and space. For more information on the WMS, or to become a member, please visit us at www.wms.org .

About Elsevier
Elsevier is a global information analytics business that helps institutions and professionals progress science, advance healthcare and improve performance for the benefit of humanity. Elsevier provides digital solutions and tools in the areas of strategic research management, R&D performance, clinical decision support, and professional education; including ScienceDirect, Scopus, SciVal, ClinicalKey and Sherpath. Elsevier publishes over 2,500 digitized journals, including The Lancet and Cell, more than 35,000 e-book titles and many iconic reference works, including Gray's Anatomy. Elsevier is part of RELX Group, a global provider of information and analytics for professionals and business customers across industries. www.elsevier.com

Media contact
Theresa Monturano, Publisher
Elsevier
+1 215-239-3711
hmsmedia@elsevier.com