Altitude, Acute Mountain Sickness, and Acetazolamide: Recommendations for Rapid Ascent

Abstract

Background: Sea level natives ascending rapidly to altitudes above 1,500 m often develop acute mountain sickness (AMS), including nausea, headaches, fatigue, and lightheadedness. Acetazolamide (AZ), a carbonic anhydrase inhibitor, is a commonly used medication for the prevention and treatment of AMS. However, there is continued debate about appropriate dosing, particularly when considering rapid and physically demanding ascents to elevations above 3,500 m by emergency medical and military personnel. Aims: Our goal in the present analysis was to evaluate and synthesize the current literature regarding the use of AZ to determine the most effective dosing for prophylaxis and treatment of AMS for rapid ascents to elevations >3,500 m. These circumstances are specifically relevant to military and emergency medical personnel who often need to ascend rapidly and perform physically demanding tasks upon arrival at altitude. Methods: We conducted a literature search from April 2018 to February 2020 using PubMed, Google Scholar, and Web of Science to identify randomized controlled trials that compared AZ with placebo or other treatment with the primary endpoint of AMS incidence and severity. We included only research articles/studies that focused on evaluation of AZ use during rapid ascent. Results: Four doses of AZ (125, 250, 500, and 750 mg daily) were identified as efficacious in decreasing the incidence and/or severity of AMS during rapid ascents, with evidence of enhanced effectiveness with higher doses. Conclusions: For military, emergency medical, or other activities involving rapid ascent to altitudes >3,500 m, doses 500-750 mg/day within 24 hours of altitude exposure appear to be the most effective for minimizing symptoms of AMS.

High Altitude Pregnancies and Vascular Dysfunction: Observations From Latin American Studies

“…However, several therapies are available for adults (men and non-pregnant women), with acetazolamide and dexamethasone (Dex) being the two best-tested drugs used as preventive medication during HA exposure (Joyce et al, 2018 ; Sydykov et al, 2021 ). Acetazolamide, a potent carbonic anhydrase inhibitor, induces metabolic acidosis leading to the activation of peripheral chemoreceptors and increased ventilatory drive during exposure to low oxygen pressure (Toussaint et al, 2021 ). On the other hand, Dex blocks the arachidonic acid pathway, decreasing inflammatory mediators like systemic prostaglandins (O'Hara et al, 2014 ).…”

Proteomic and Morphological Profiling of Mice Ocular Tissue During High-altitude Acclimatization Process: An Animal Study at Lhasa

“…High-altitude environment is complicated and hostile, it is a great challenge for those who rush entry into plateau from lowland. 43 As we know that body weight reflected the total stress level of the body, 44 we found an obvious body weight decreasing in mice at the acute phase of 3 days exposure. As for the components of the ocular tissue, we focused on the morphological changes of cornea, retina and choroid.…”

The Protective Effect of a Novel Cross-Linked Hemoglobin-Based Oxygen Carrier on Hypoxia Injury of Acute Mountain Sickness in Rabbits and Goats

“…Acute mountain sickness is an anoxic reaction symptom that can endanger life seriously if not treated ( Rolla et al, 2002 ). Currently, the major prevention and treatment measures for AMS included oxygen inhalation, glucocorticoid, and Acetazolamide ( Tang et al, 2014 ; Ou et al, 2020 ; Toussaint et al, 2020 ). Oxygen inhalation is most effective for AMS.…”

“…Besides, the effect of oxygen inhalation is short. Other preventive measures for severe AMS include Rhodiola rosea (RhRo), acetazolamide, and dexamethasone ( Tang et al, 2014 ; Ou et al, 2020 ; Toussaint et al, 2020 ). However, these measures are unable to improve tissue hypoxia fundamentally and are unsuitable for emergencies since they take a long time to take effect.…”