Ibuprofen Decreases Likelihood of Altitude Sickness

Ricki Lewis, PhD

March 20, 2012

March 20, 2012 — Ibuprofen appears to lower the risk of developing acute altitude sickness, according to a report from Grant S. Lipman, MD, from Stanford University School of Medicine in California, and colleagues, published online March 20 in the Annals of Emergency Medicine.

Approximately 25% of the people who travel to altitudes of 8250 feet or higher suffer from acute mountain sickness, which includes headaches, nausea, dizziness, fatigue, and vomiting> If left untreated, altitude sickness may progress to high-altitude cerebral edema, a potentially fatal condition. Symptoms typically start 6 to 12 hours after reaching the high altitude. Gradual ascent lowers the risk of developing acute mountain sickness.

Dr. Lipman and colleagues propose that an anti-inflammatory drug could counter the brain inflammation that is a response to decreased atmospheric pressure at higher elevations. Although this connection is intuitive, the researchers write, evidence for efficacy has been inconclusive.

To test the hypothesis in a double-blind, placebo-controlled study, the investigators enrolled 58 men and 28 women, all of whom were healthy and who live at low altitudes. The study was conducted over the course of 4 weekends in July and August 2010. Study participants and researchers gathered for the first night at 4100 feet in an area of the White Mountains of California. The next morning, each participant received either 600 mg of ibuprofen or placebo. They were driven to a staging area at 11,700 feet, received a second dose at 2 pm, hiked to 12,570 feet, and received the third dose before spending the night at that elevation.

The participants completed questionnaires asking about symptoms and demographics and had their oxygen saturation measured before receiving the first dose at 4100 feet, and before and after the final ascent.

Nineteen of the 44 participants (43%) given ibuprofen suffered altitude sickness, as did 29 of the 42 control participants (69%). The absolute reduction in incidence was 26% (odds ratio, 0.3; 95% confidence interval, 0.1 - 0.8). The researchers observed a non–statistically significant lower symptom severity in the hikers who took the ibuprofen.

Ibuprofen offers advantages over other medications available to prevent mountain sickness (acetazolamide and dexamethasone), the researchers write. It does not have the adverse effects associated with the other 2 drugs (nausea, dizziness, and fatigue for acetazolamide; delirium depression, insomnia, mania, adrenal suppression, and hyperglycemia for dexamethasone). Moreover, ibuprofen is easily obtained, and can be effective if taken 6 hours before ascension compared with acetazolamide, which must be taken the day before the ascent.

"We found that ibuprofen was effective in reducing the incidence of acute mountain sickness compared with placebo, with the odds of experiencing acute mountain sickness about 3 times greater in participants receiving placebo rather than prophylactic ibuprofen," the researchers conclude.

A possible limitation of the study is acclimatization at 4100 feet, although this is unlikely because of the high incidence of symptoms in the control group. Possible confounders include variability in diet, unreported relevant physiological conditions, and the fact that the participants self-selected and may not represent other groups of hikers.

The researchers caution that they chose the study conditions to represent experiences of recreational hikers, so extrapolation to those hiking at higher altitudes may not be valid.

The authors have disclosed no relevant financial relationships.

Ann Emerg Med. Published online March 20, 2012.