26 Sep - 2 Oct 2014 #726

Step by step

Travellers to altitudes need to be encouraged to go up gradually without the use of drugs
Dhanvantari by Buddha Basnyat, MD

Now that the trekking season is here, it may be worthwhile to go over some important points about Diamox, the most commonly used drug for prevention of acute mountain sickness (AMS). Trekkers and high-altitude pilgrims take Diamox for both prevention and treatment of AMS.

AMS is a common problem at high altitude(> 2500m) and usually presents with headache, nausea tiredness, and fatigue. More than altitude, it is the speed at which travellers make their ascents that determine the severeness of AMS. The best way to prevent acute mountain sickness is thus by planning an itinerary that allows for gradual acclimatisaton.

As far as possible, it is best to avoid use of drugs while in the mountains. The Himalayan Rescue Association strongly recommends travellers to make gradual ascent without using any drugs. However there are situations where it may not be possible to ascend slowly.

Rescuers are required to go up rapidly to high altitudes. For logistic reasons, it may not be possible for trekkers and climbers to spend the night at an optimal altitude. Furthermore, airports in places like Lhasa, Tibet (3,490 m), La Paz, Bolivia (4,058m), Leh,Ladak (3500m) may cause travellers to arrive at a high altitude without the chance to acclimatise en route.

In case of such circumstances, travellers who do not take diamox before the trip, are susceptible to AMS which can sometimes progress to life-threatening high altitude pulmonary edema ( HAPE) or high altitude cerebral edema ( HACE). Many travellers like pilgrims often forget to ascend gradually in their fervour of reaching the ‘divine land’.

Sudden military deployment to high altitude regions of the world, such as the HinduKush in Afghanistan, may necessitate drugprophylaxis for prevention of AMS. A fast-growing population of climbers are also incorrectly being advised by physicians to use prophylactic medicine to both improve performance and achieve their summit dream.

In a publication in the British Medical Journal in 2000, Dumont and colleagues had stated that only 750 mg/day of Diamox (acetazolamide) would prevent AMS. However, recent articles, which include studies done after 2000 (many of which were conducted in the Himalayas), have shown that a much lowerdose (250 mg/day) of diamox is adequate.

For travellers without sulpha allergy, it is recommended to take Diamox a day before the trip at a dosage of 125 mg in the morning and evening and continue for 2 to 3 days in the mountains. Other drugs including Gingko Biloba and Ibuprofen have been found to prevent AMS. But due to its proven efficacy over the years in a large number of trials with an acceptable side-effect profile, Diamox continues to be the most commonly used drug.

Diamox causes a tingling sensation of the fingers and toes, which for many is very bothersome. It also makes carbonated beverages taste flat.

Diamox also helps prevent periodic breathing (literally, trying to “catch your breath” while sleeping) at high altitude. This is a very common problem which sometimes triggers anxiety attacks. Diamox decreases the hypoxemic (low oxygen) spells during sleep and successfully treats this problem.

In conclusion, travellers to altitudes need to be encouraged to go up gradually without the use of drugs, including Diamox to enhance acclimatisation. However, in certain instances,chemoprophylaxis may be useful. In those cases, low-dose ( 250 mg\day) of Diamox is the drug of choice.

Read also:

Altitude illness awareness, Buddha Basnyat

Conquering heights, Buddha Basnyat

Mountain warning, Buddha Basnyat

Killer Climbs, Buddha Basnyat

Making safety a high priority, Buddha Basnyat