Acetylsalicylic Acid (Aspirin) Analog versus Acetazolamide for Acute Mountain Sickness

In Volume 9, Number 1 (2008) of the journal High Altitude Medicine & Biology, published by the International Society for Mountain Medicine, Bengt Kayser, Ronald Hulsebosch, and Frank Bosch report a randomized controlled study of the acetylsalicylic acid (aspirin) analog, calcium carbasalate, compared with a placebo and acetazolamide (Diamox) during a rapid ascent of Mount Kilimanjaro (5896 meters or 19,344 feet). The dose of calcium carbasalate used was 380 mg per day; the dose of acetazolamide was 500 mg per day. Ascent of Mt. Kilimanjaro is typical of a rapid ascent that does not require technical mountaineering skills, and is undertaken by numerous persons who are neither experienced in high altitude travel nor particularly knowledgeable about high altitude illness.

The results showed that calcium carbasalate did not prevent acute mountain sickness (AMS) or headache. A very interesting finding was that more than half the individuals taking acetazolamide developed AMS. This may indicate that the dose taken is not sufficient in general, or perhaps only that the ascent rate was too fast for this (or any) dose of acetazolamide to be effective in prevention of AMS. This is even more intriguing, and deserves further investigation, because the trend in recent clinical recommendations has been to use lower doses (e.g., 250 mg per day) of acetazolamide for the purpose of high altitude acclimatization, in order to achieve a beneficial effect while minimizing the side effects. So, it is very important to understand which circumstances of ascent call for a higher dosing regimen.

AMS is a very debilitating disorder, and is likely the harbinger of high altitude cerebral edema (brain swelling). At the very least, it causes headache, poor appetite, fatigue, nausea, and soft tissue swelling, and is markedly disruptive for adventures and recreation at high altitude. This particular study supports our current understanding that non-steroidal antiinflammatory drugs and common analgesics, such as aspirin, ibuprofen, and acetaminophen, are not useful to prevent AMS, and may only serve to mask an important symptom (headache) that indicates when a person is entering a dangerous physiological situation. Of course, if the patient and observers are confident that the headache is mild and that AMS is not progressing, it is reasonable to treat the headache with an analgesic.

photo courtesy of www.7summits.com

Tags: acetazolamide, acute mountain sickness, AMS, wilderness medicine, outdoor medicine, healthline

Labels: acetazolamide, acute mountain sickness, AMS, calcium carbasalate, high altitude, high altitude medicine

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Ginkgo biloba for Prevention of Acute Mountain Sickness

The fourth issue of Volume 18 of the journal Wilderness & Environmental Medicine has recently been published. The lead article is entitled "Ginkgo biloba Decreases Acute Mountain Sickness in People Ascending to High Altitude at Ollague (3696 m) in Northern Chile," authored by Fernando A. Moraga and his associates.

The article describes a study, the objective of which was to determine the effect of Ginkgo biloba in preventing acute mountain sickness (AMS) at an altitude of 3696 meters (12,126 feet) in participants without high-altitude experience. Thirty-six persons who reside at sea level were transported by ground transportation over 8.5 hours to an altitude of 3696 meters. The study participants were divided into three equal groups of 12 persons each. One group received Ginkgo biloba in a dose of 80 milligrams every 12 hours by mouth, one group received acetazolamide (Diamox, a drug commonly used to hasten acclimatization to altitude or to treat AMS) in a dose of 250 milligrams every 12 hours by mouth, and the final group received a placebo (e.g., no active drug). Each group began its treatment 24 hours before ascending and continued treatment during the 3-day stay at altitude. A standard Lake Louise Questionnaire was administered to determine the Self-Report Score, which is an accepted method for determining the presence and degree of AMS. In addition, selected physiological measurements were taken.

The results are the most compelling data to date supporting the efficacy of Ginkgo biloba in prevention of AMS. The group taking the Ginkgo biloba had no increase in their AMS score (which is remarkable), while the acetazolamide and placebo groups showed increases of 36% and 54%, respectively. The authors concluded that their study provides evidence supporting the use of Gingko biloba in the prevention of AMS, demonstrating that 24 hours of pretreatment with Gingko biloba and subsequent maintenance during exposure to high altitude are sufficient to reduce the incidence of AMS in participants with no previous high-altitude experience.

No doubt, others will attempt to replicate this investigation. If the results are corroborated, then Ginkgo biloba may prove to be a very useful adjunct in the prevention and treament of AMS.

Ginkgo biloba plant image courtesy of www.artofbonsai.org

Tags: Ginkgo biloba ,AMS, altitude, acetazolamide, high altitude, wilderness medicine, outdoor medicine, healthline

Labels: acetazolamide, acute mountain sickness, AMS, Ginkgo, Ginkgo biloba, high altitude, high altitude medicine

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