From the Guidelines
For preventing altitude sickness, Diamox (acetazolamide) is recommended at a dosage of 125 mg twice daily, starting 24-48 hours before ascending to high altitude and continuing for at least 48 hours after reaching the highest altitude or until descent begins. This dosage is based on recent studies, including a 2021 European Respiratory Society guideline on non-cpap therapies for obstructive sleep apnoea 1, which highlights the benefits of acetazolamide in improving nocturnal oxygen saturation and reducing residual sleep apnoea at high altitudes.
The medication works by causing the kidneys to excrete bicarbonate, creating a mild metabolic acidosis that stimulates breathing and improves oxygen uptake, essentially pre-acclimatizing the body. Key benefits of using Diamox for altitude sickness prevention include:
- Improved nocturnal oxygen saturation
- Reduced residual sleep apnoea
- Reduced nocturnal transcutaneous carbon dioxide partial pressure
- Reduced excessive blood pressure increases
Common side effects of Diamox include:
- Increased urination
- Tingling sensations in the fingers and toes
- Altered taste of carbonated beverages
- Rarely, nausea or drowsiness
- Paraesthaesia, vertigo, and unpleasant taste, as reported in the study 1
It is essential to note that Diamox should be avoided by those allergic to sulfa drugs, and patients with kidney disease or severe liver disease should consult their doctor before use. While taking Diamox, it's crucial to stay well-hydrated to prevent dehydration and potential kidney stone formation. Additionally, medication is just one component of altitude sickness prevention; gradual ascent, proper hydration, and avoiding alcohol and sedatives are equally important measures.
From the Research
Recommended Dosage and Usage of Diamox (Acetazolamide)
The recommended dosage and usage of Diamox (acetazolamide) for preventing altitude sickness are as follows:
- The use of prophylactic acetazolamide in a dosage of 125 mg every 12 hours is highly effective at diminishing the risk of high-altitude illness (HAI) 2.
- A study found that 125 mg bd of acetazolamide is not significantly different from 375 mg bd in the prevention of acute mountain sickness (AMS) 3.
- It is suggested that the beginning of pre-treatment with low-dose acetazolamide at least two days before arrival at high altitude would be of greater beneficial effect on AMS development 4.
Prevention of Altitude Sickness
The prevention of altitude sickness using acetazolamide is supported by several studies:
- Acetazolamide has been shown to be an effective way to help prevent HAI on rapid arrival to altitudes over 3350 m (11 000 feet) 2.
- The risk of HAI on rapid arrival to altitudes over 3350 m (11 000 feet) has been shown to range from 35% to nearly 50% 2.
- Acetazolamide prevents acute mountain sickness (AMS) by inhibition of carbonic anhydrase 5.
Side Effects and Comparisons
The side effects and comparisons of acetazolamide with other drugs are as follows:
- There was more paresthesia in the 375-mg bd group compared to the 125-mg bd group 3.
- Dexamethasone, used prophylactically, also reduces the symptoms of acute mountain sickness partly due to its euphoric effect 6.
- There is no comparison of the effectiveness of acetazolamide with other drugs used for treating acute mountain sickness such as steroids and calcium channel blocking drugs 6.