Clinical Trial: Ibuprofen vs Acetaminophen for AMS Prevention

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Ibuprofen vs Acetaminophen in the Prevention of Acute Mountain Sickness: A Double Blind, Randomized Controlled Trial

Brief Summary: AMS (acute mountain sickness) affects those who ascend too high (>2000m) too fast. Acetazolamide is an effective drug for the prevention of AMS where proper acclimatization with gradual ascent may not be an option. AMS presents with headache and other non-specific symptoms such as nausea, tiredness, and dizziness. Because of the side effects of acetazolamide such as a tingling sensation, other drugs have been investigated to see if they will prevent AMS. Ibuprofen has recently been shown to prevent AMS. In this present study the investigators want to see if acetaminophen can also prevent AMS as acetaminophen unlike ibuprofen does not have gastric side effects. Second, because acetaminophen has much less anti-inflammatory component than ibuprofen, it may also provide some insight into the pathophysiology of AMS if acetaminophen were found to be effective in the prevention of AMS.

Detailed Summary:

Acute mountain sickness (AMS) is a well-known disorder in sojourners to high altitude (>2000m) characterized by headache, nausea and tiredness, akin to hangover-like symptoms. The Lake Louise criteria for AMS was primarily developed to allow uniformity in comparing the prevalence of AMS in different high altitude regions.

Proper acclimatization by gradual ascent to high altitude is the best means of prevention of AMS. However there may be instances when rapid ascents may be necessary. Acetazolamide is the best known drug for the prevention of AMS. Because of its well-known side effects like tingling sensation in the fingers and toes and its potential sulpha allergy (acetazolamide is a sulpha-based drug) problems, alternative drugs in the prevention of AMS have been sought. Recently two randomized controlled trials have shown the usefulness of ibuprofen 600 mg tid orally in the prevention of AMS.

The exact mechanism causing AMS is unknown although evidence points to a process in the central nervous system. The mechanism of headache, the main feature in most AMS patients, is probably multifactorial with various chemical and mechanical factors activating a final common pathway, the trigeminovascular system. Triggering factors associated with high altitude hypoxia leading to AMS may include arachidonic acid metabolites amongst others such as serotonin, histamine, and nitric oxide. The response in AMS prevention to non-steroidal anti-inflammatory drugs (NSAIDs) and steroids provides indirect evidence of arachidonic acid pathway and inflammation in the genesis of AMS.

But in contrast, the role of drugs such as acetaminophen which primarily provide analgesia by blunting the meningovascular receptors known to mediate nociception is unknown in the prevention of AMS. Crucially if
Sponsor: Mountain Medicine Society of Nepal

Current Primary Outcome: Diagnosis of Acute Mountain Sickness (AMS) [ Time Frame: Upon reaching 5000m altitude (Lobuche) of Nepal Himalaya. Average stay of the trekkers at this altitude is expected about a day or more. The assessment of the participants will be done next day (after spending overnight) upon their arrival. ]

AMS diagnosis will be done using Lake Louise Questionnaire (LLQ) which requires a score of three or greater with the mandatory presence of headache and at least one of the following symptoms: dizziness or light-headedness, fatigue, gastrointestinal (GI) symptoms (nausea/vomiting), or difficulty sleeping.

LLQ is a self-report symptom questionnaire and it will be assessed among all the study participants upon arrival to the study end point i.e. 5000m altitude (Lobuche) as specified above.



Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Blood Oxygen Saturation (SPO2) [ Time Frame: Upon reaching 5000m altitude (Lobuche) of Nepal Himalaya. Average stay of the trekkers at this altitude is expected about a day or more. The assessment of the participants will be done next day (after spending overnight) upon their arrival. ]
    Blood oxygen saturation (percentage of oxygen in the blood) among all the study participants will be measured using Pulse Oximetry. The percentage of oxygen in the blood measured will be abbreviated as SPO2 in the spreadsheet.
  • Heart Rate (HR) [ Time Frame: Upon reaching 5000m altitude (Lobuche) of Nepal Himalaya. Average stay of the trekkers at this altitude is expected about a day or more. The assessment of the participants will be done next day (after spending overnight) upon their arrival. ]
    Heart rate (HR) will be assessed among all the study participants using Pulse Oximetry. The heart rate measured in the study will be abbreviated as HR in the spreadsheet.
  • High Altitude Headache (HAH) [ Time Frame: Upon reaching 5000m altitude (Lobuche) of Nepal Himalaya. Average stay of the trekkers at this altitude is expected about a day or more. The assessment of the participants will be done next day (after spending overnight) upon their arrival. ]
    High altitude headache (HAH) and its severity will be scored based on a Visual Analog Scale (VAS) and the headache score identified on the designated LLQ score upon arrival to the study end point i.e. 5000m altitude (Lobuche).


Original Secondary Outcome: Same as current

Information By: Mountain Medicine Society of Nepal

Dates:
Date Received: September 14, 2014
Date Started: October 2014
Date Completion:
Last Updated: March 16, 2016
Last Verified: March 2016