View clinical trials related to Altitude Sickness.
Filter by:This study is aimed to assess the efficacy of combined treatment with two antihypertensive agents (telmisartan and nifedipine) in subjects with mild hypertension exposed to high altitude.
The aim of this investigation is to determine the incidence of silent interstitial pulmonary edema by chest ultrasound at moderate altitude (3905m). Secondary endpoints are to detect a suspected association with acute mountain sickness (AMS), co-morbidities and endothelial dysfunction (marker of hypoxia responses, endothelial damage and inflammation).
Acute exposure of the unacclimatized human body to high altitude leads to health complications, such as loss of exercise performance capacity and fatigue. The investigators have found that the combination of the xanthine drug theophylline and the endothelin receptor antagonist ambrisentan improves the exercise performance capacity of rats under simulated high altitude. In young, healthy human volunteers, this combination of drugs has not increase toxicity over the single compounds under sea-level conditions. The aim of this study is to test whether the combination of theophylline, supplied as its more soluble formulation aminophylline, and ambrisentan, are also safe to take under simulated high altitude of 4,267 meters, under both resting and exercising conditions. The study also aims to test whether this drug combination improves exercise capacity in humans. In this study, human subjects will be randomized to one of four treatment sequences and receive the same study drug(s) throughout all procedures. The study consists of an initial exercise test, followed by two cycles of drug testing at simulated high altitude: Cycle 1 - resting subjects receiving study drug at simulated altitude and continually monitored for safety with pharmacodynamic and pharmacokinetic assessments; and Cycle 2, the same as Cycle 1, with the addition of exercise testing. It is hypothesized that the combination of aminophylline and ambrisentan is not only safe under simulated high altitude, but also improves exercise performance capacity, in comparison with placebo.
Acute mountain sickness (AMS) is a syndrome of nonspecific symptoms and is therefore subjective. The Lake Louise Consensus Group defined acute mountain sickness as the presence of headache in an unacclimatized person who has recently arrived at an altitude above 2,500 m plus the presence of one or more of the following: gastrointestinal symptoms (anorexia, nausea, or vomiting), insomnia, dizziness, and lassitude or fatigue. An increase in RBC mass is a natural feature of altitude acclimatization. Hypoxia-induced erythropoietin (EPO) secretion begins hours after ascent and stimulates bone marrow production of red blood cells, but this takes weeks to effect an increase in red cell mass . Therefore, it is feasible that EPO therapy weeks before altitude exposure decrease high altitude illness. In 1996, Young et al in U.S. Army Research Institute of Environmental Medicine (USARIEM) reported that autologous erythrocyte infusion did not ameliorate the decrement in maximal oxygen uptake at 4,300m altitude despite increasing arterial oxygen carrying capacity. On the basis of this report, USARIEM did not recommend use of recombinant EPO for altitude acclimatization. However, increases in erythrocyte count, hematocrit and hemoglobin associated with EPO therapy have been shown to decrease fatigue and increase work capacity and exercise tolerance. In addition, improvement in CNS function and cognitive ability has been noted with EPO therapy. Subjective benefits include improvement in sleep habits, tolerance to cold; decreased dyspnea, anginal symptoms and tachycardia and improved appetite, all of which are symptoms associated with high altitude illness. The investigators also reported improved muscle energy metabolism with EPO in dialysis patients, but not with RBC transfusion. In this study, the investigators will conduct a randomised controlled trial to assess the effect of EPO administration on AMS at an altitude of 4,130 m.
High altitude pulmonary hypertension, a form of altitude illness that occurs in long-term residents at altitudes >2500 m, is characterized by dyspnea, hypoxemia, impaired exercise performance and hypertension in the pulmonary circulation. Whether sleep related breathing disturbances, common causes of nocturnal hypoxemia in lowlanders, are also prevalent in highlanders and promote pulmonary hypertension in highlanders is unknown. Therefore, the current study will investigate whether highlanders with high altitude pulmonary hypertension have a greater prevalence of sleep apnea than healthy highlanders and lowlanders.
This safety study is the first in a series of studies testing the application of the combination of aminophylline and methazolamide.
This is a Phase I, three period, two sequence, open-label, randomized, crossover study, with the primary objective of testing the safety and tolerability of combined oral doses of theophylline and bambuterol in healthy human subjects. The secondary objective is to assess the pharmacokinetic profiles of theophylline and bambuterol when administered alone or in combination. It is hypothesized that the combination of these drugs is generally safe, and that no drug interaction can be observed.
Traditional folk medicine in the Arctic and Himalayan areas used Rhodiola species to enhance physical endurance, prevent aging, resist acute mountain sickness (AMS), and to treat fatigue, depression, anemia, impotence and respiratory infections. Rhodiola crenulata are widely used to prevent AMS in Himalayan areas and Lhasa in Tibet but none was examined by human study. The investigators conducted a randomized, double blind, placebo controlled, crossover study to investigate the efficacy of Rhodiola crenulata in preventing AMS.
This is a Phase I, three period, two sequence, open-label, randomized, crossover study, with the primary objective of testing the safety and tolerability of combined oral doses of aminophylline and ambrisentan in healthy human subjects. The secondary objective is to assess the pharmacokinetic profiles of theophylline (aminophylline) and ambrisentan when administered alone or in combination. It is hypothesized that the combination of these drugs is generally safe, and that no drug interaction can be observed.
The objective of this study is to determine the efficacy of metoclopramide in relieving the symptoms of Acute Mountain Sickness (AMS). It is our hypothesis that the combined antiemetic and analgesic effects of metoclopramide (which has been study-proven to be effective in relieving symptoms of migraine headache) will prove to be more efficacious in relieving symptoms of acute mountain sickness than the standard, previously-studied analgesic medication, ibuprofen.