From the Guidelines
Azetazolamide, also known as acetazolamide, is a carbonic anhydrase inhibitor that can be used to treat various conditions, including glaucoma, altitude sickness, and certain types of seizures, with a typical dosage ranging from 125-1000mg daily, depending on the condition being treated. The medication works by inhibiting the enzyme carbonic anhydrase, which reduces fluid production in the eye, increases urination of bicarbonate, and alters brain electrical activity 1.
Key Uses and Dosages
- For altitude sickness prevention, the typical dosage is 125-250mg twice daily, starting 1-2 days before ascent and continuing for 2-3 days at high altitude.
- For glaucoma, doses range from 250-1000mg daily, often divided.
- As a diuretic for conditions like edema, 250-375mg once daily is common.
Mechanism of Action and Side Effects
The medication's mechanism of action involves inhibiting carbonic anhydrase, which has various effects depending on the condition being treated 1. Common side effects include:
- Tingling in hands and feet
- Altered taste (especially making carbonated beverages taste flat)
- Increased urination
- Fatigue
Precautions and Contraindications
Azetazolamide should be used cautiously in patients with kidney or liver disease, and those allergic to sulfa drugs should avoid it 1. Adequate hydration is important while taking this medication to prevent kidney stones.
Use in Obstructive Sleep Apnea
There is limited evidence on the use of azetazolamide in obstructive sleep apnea (OSA), but studies suggest that carbonic anhydrase inhibitors like acetazolamide may reduce sleep apnea intensity and improve oxygenation 1. However, more research is needed to fully understand the effects of azetazolamide on OSA.
From the FDA Drug Label
DESCRIPTION Acetazolamide, an inhibitor of the enzyme carbonic anhydrase, is a white to faintly yellowish white crystalline, odorless powder, weakly acidic, very slightly soluble in water and slightly soluble in alcohol. The chemical name for acetazolamide is N-(5-Sulfamoyl-1,3,4-thiadiazol-2yl)-acetamide and has the following structural formula: Acetazolamide is available for intravenous use, and is supplied as a sterile powder requiring reconstitution. Each vial contains acetazolamide sodium equivalent to 500 mg of acetazolamide. The bulk solution is adjusted to pH 9.6 using sodium hydroxide and, if necessary, hydrochloric acid prior to lyophilization. The drug azetazolamide is actually referred to as acetazolamide in the provided text. Key points about acetazolamide include:
- It is an inhibitor of the enzyme carbonic anhydrase
- It is available for intravenous use
- Each vial contains acetazolamide sodium equivalent to 500 mg of acetazolamide 2
From the Research
Azetazolamide Overview
- Azetazolamide is not directly mentioned in the provided studies, however, the studies discuss acetazolamide and methazolamide, which are related compounds.
- Acetazolamide is a carbonic anhydrase inhibitor used for various conditions, including altitude sickness, sleep apnea, and glaucoma 3.
- Methazolamide is a methylated lipophilic analogue of acetazolamide, with higher lipid solubility and fewer side effects 4.
Side Effects
- Acetazolamide increases the risk of side effects such as paraesthesias, taste disturbances, polyuria, and fatigue 3.
- The risk of these side effects is dose-dependent, with higher doses increasing the risk of paraesthesias and taste disturbances 3.
- Methazolamide causes less fatigue side effects than acetazolamide and may be an alternative for high-altitude illnesses prophylaxis and treatment 4.
High-Altitude Illnesses
- Acetazolamide is a useful prophylactic for acute mountain sickness, causing marked reduction in headache, nausea, vomiting, and weakness 5.
- Methazolamide has similar efficacy to acetazolamide in preventing symptoms of acute mountain sickness, but with fewer side effects 6.
- Acetazolamide dosing for rapid ascent to elevations above 3,500m is recommended to be 500-750mg/day within 24 hours of altitude exposure 7.
Comparison of Acetazolamide and Methazolamide
- Methazolamide has higher lipid solubility and fewer side effects than acetazolamide 4.
- Methazolamide may be an alternative to acetazolamide for high-altitude illnesses prophylaxis and treatment, but more in-depth clinical trials are needed to fully evaluate its efficacy 4.
- A lower dose of methazolamide may have similar prophylaxis and treatment efficacy to a higher dose of acetazolamide 4, 6.