Lower dose of Acetazolamide not effective for Mountain Sickness, finds study

Acetazolamide is a carbonic anhydrase inhibitor commonly prescribed for Acute mountain sickness. It is generally prescribed at 125mg twice a day dosing on the day or an evening prior to the ascent.

Lower doses of Acetazolamide of 62.5mg twice a day failed to demonstrate equal effectiveness as 125mg twice a day dose for the prevention of acute mountain sickness, according to a recent trial published in the journal ' The American Journal of Medicine' 2020.

The trial was carried out in 2019 at California. The study was a double-blind, randomized, controlled noninferiority trial. Healthy, eligible participants were recruited and were given acetazolamide twice daily starting the evening prior to ascent from 1240 m (4100 ft) to 3810 m (12,570 ft) over 4 hours. A total of 106 participants were analysed in the trial. Participants were randomly divided into 2 groups of 1:1 with 62.5mg twice a day dosing given to 1 group and standard 125mg twice a day given to another group.

The primary outcome of measurements was acute mountain sickness incidence which included headache, Lake Louise Questionnaire ≥3, and any other symptom.

Out of 106 participants who were analysed, 51 (48%) were randomized to 125 mg group and 55 (52%) to 62.5 mg group. They had a combined acute mountain sickness incidence of 53 (50%) and mean severity of 3 (± 2.1).

Key findings of the study were:

• The 62.5-mg group failed to fall within the prespecified 26% noninferiority margin for acute mountain sickness incidence (62.5 mg = 30 [55%] vs 125 mg = 23 [45%].

• Participants in the 62.5-mg group had a higher risk and moderate risk of acute mountain sickness and number need to harm was 9.

• Participants in the 125mg group had a number to treat of 4.8

• Increased acute mountain sickness incidence and symptom severity corresponded to lower weight-based and body mass index dosing, with similar side effects between groups.

By this study, the researchers concluded that Acetazolamide 62.5 mg twice daily failed to demonstrate equal effectiveness to 125 mg twice daily for prevention of acute mountain sickness. With increased risk and no demonstrable symptomatic or physiologic benefits, acetazolamide 62.5 mg twice daily should not be recommended for acute mountain sickness prevention.

To read more about the study, Click the following link: 

https://doi.org/10.1016/j.amjmed.2020.05.003