Study at Mt. Everest finds acetaminophen as effective as ibuprofen for high-altitude headache
Fewer side effects suggest acetaminophen could be drug of choice

BOSTON - May 14, 2003 - In a study conducted near the Mt. Everest Base Camp in Nepal, a Massachusetts General Hospital (MGH) resident physician and his colleagues have found that acetaminophen is as effective as ibuprofen in treating high-altitude headache. Because acetaminophen has fewer side effects than medications like ibuprofen, this finding suggests that acetaminophen may be the best choice for those who experience headaches when they travel to altitudes of more than 2,000 meters (about 6,600 feet). The report appears in the Journal of Emergency Medicine.

"If you have two equally effective drugs for a condition, it makes sense to use the one with the fewest probable side effects," says study leader N. Stuart Harris, MD, MFA, who is currently completing his residency in the Harvard-Affiliated Emergency Residency Program at MGH and Brigham and Women's Hospital. Working with two colleagues, he spent three months in Nepal in the Spring of 1999, investigating whether acetaminophen might be as effective as ibuprofen, which previous research had shown was effective for high-altitude headache.

A severe, throbbing headache is the primary symptom of acute mountain sickness, a syndrome that also can include nausea, sleeplessness, loss of appetite and fatigue. Caused by reduced levels of oxygen at high altitudes, mountain sickness can lead to serious, even fatal complications characterized by edema - a buildup of fluid - in the lungs or brain.

Harris and his colleagues wanted to investigate acetaminophen's potential role in treating high-altitude headache because the medication does not cause gastrointestinal problems, which ibuprofen and other non-steroidal anti-inflammatory drugs (NSAIDS) sometimes can. In addition, one previous study showed that patients with high-altitude pulmonary edema were more likely to have taken NSAIDS, suggesting a possible association of those drugs with the dangerous complication.

Conducting the first prospective, randomized, double-blind study of acetaminophen for high-altitude headache, Harris surveyed hikers arriving at a Nepal camp at 4,200 meters (13,400 feet), a day's hike below the established Everest Base Camp. Over a period of six weeks, he enrolled 74 hikers who reported symptoms of high-altitude headache. Study participants were asked to complete questionnaires about their medical history and a standard survey for headache symptoms and severity. Then they received identical-appearing capsules containing either acetaminophen or ibuprofen. At 30, 60 and 120 minutes after taking the capsules, they again completed the headache survey.

Analysis of the results showed that both groups reported similar levels of pain relief during the two-hour study period. Both groups also reported slightly decreased levels of nausea during the study period, and there were no reports of more serious altitude sickness symptoms.

"Although many factors are involved in the development of HAPE [high-altitude pulmonary edema], one of the most significant is a constriction of the blood vessels in the lungs," says Harris. "There have been animal studies suggesting that NSAIDS could contribute to this constriction. HAPE is extremely rare, and our study was too small to find any impact of the drugs on HAPE. But the condition's potential seriousness suggests that any possible increase in risk should be avoided."

Harris's coauthors are Richard Wenzel, MD, MSc, of Medical College of Virginia; and Stephen Thomas, MD, of the MGH Department of Emergency Medicine. The study was supported by an unrestricted grant from McNeil Pharmaceuticals, makers of Tylenol, but the authors had complete and exclusive control of the study and its reporting.

Massachusetts General Hospital, established in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH conducts the largest hospital-based research program in the United States, with an annual research budget of more than $350 million and major research centers in AIDS, cardiovascular research, cancer, cutaneous biology, neurodegenerative disorders, transplantation biology and photomedicine. In 1994, MGH and Brigham and Women's Hospital joined to form Partners HealthCare System, an integrated health care delivery system comprising the two academic medical centers, specialty and community hospitals, a network of physician groups, and nonacute and home health services.

Media Contact: Sue McGreevey, MGH Public Affairs

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