Acetazolamide, often recognized by its brand name Diamox, is a medication classified as a carbonic anhydrase inhibitor. It is available in various forms, including oral tablets, extended-release capsules, and solutions for injection. This medication influences the body’s fluid balance and is used to manage a range of medical conditions. Its actions extend to the kidneys, eyes, and central nervous system, producing several therapeutic effects.
What Acetazolamide Treats
Acetazolamide is prescribed for several medical conditions, most notably glaucoma, which involves elevated pressure within the eye that can lead to vision loss. It works to reduce intraocular pressure, making it a common treatment option for both chronic open-angle glaucoma and acute angle-closure glaucoma, often used short-term until surgery can be performed.
The medication also plays a role in treating and preventing symptoms of altitude sickness, also known as acute mountain sickness. When ascending to high altitudes quickly, acetazolamide can help alleviate symptoms such as headaches, fatigue, nausea, and shortness of breath. It aids in acclimatization to lower oxygen environments.
Acetazolamide acts as a diuretic, helping the body expel excess salt and water. This makes it useful for treating certain types of edema, including fluid retention caused by heart failure or other medications. It is also used as an add-on treatment for certain types of seizures. Acetazolamide also treats idiopathic intracranial hypertension, a condition characterized by raised brain pressure of unclear cause.
How Acetazolamide Works
Acetazolamide functions by inhibiting an enzyme called carbonic anhydrase, which is present in various tissues throughout the body, including red blood cells and the kidneys. This enzyme typically facilitates a reaction that forms carbonic acid from carbon dioxide and water. By blocking carbonic anhydrase, acetazolamide causes carbonic acid to accumulate.
This accumulation leads to a decrease in blood pH, making the blood more acidic. In the kidneys, this inhibition prevents the reabsorption of bicarbonate, sodium, and chloride, leading to their increased excretion in urine along with water. This diuretic effect helps reduce fluid volume and can lower blood pressure. In the eyes, acetazolamide decreases the production of aqueous humor, the fluid that fills the front part of the eye, thereby reducing intraocular pressure.
Common Experiences and Side Effects
Patients taking acetazolamide often report common side effects. Tingling sensations, often described as “pins and needles,” are common, typically affecting the hands, feet, or around the mouth. These sensations, known as paresthesias, may be dose-dependent and can sometimes be managed by adjusting the dosage.
An altered sense of taste, including a metallic or bitter taste, which can sometimes lead to a decreased appetite, is another side effect. Gastrointestinal disturbances such as nausea, vomiting, or diarrhea also occur. Drowsiness and fatigue are common, potentially affecting concentration or tasks requiring alertness, such as driving. Increased urination is expected due to the medication’s diuretic properties, and increased thirst may also occur.
More serious side effects, though less common, warrant immediate medical attention. These include:
- Signs of a severe allergic reaction, such as hives, swelling of the face, lips, tongue, or throat, and difficulty breathing.
- Electrolyte imbalances like low potassium or sodium levels, and metabolic acidosis (where the blood becomes too acidic). Symptoms may include muscle cramps, weakness, rapid breathing, or confusion.
- Kidney stones, characterized by pain in the side or lower back, blood in the urine, or painful urination.
- Severe skin reactions, such as Stevens-Johnson syndrome, which can present with flu-like symptoms, fever, and a spreading red or purple rash that may blister and peel.
Important Considerations for Use
When taking acetazolamide, follow the specific dosage instructions provided by a healthcare provider, as the dose depends on the condition being treated. For instance, doses vary significantly by condition. Take the medication with a full glass of water and maintain adequate hydration to prevent dehydration due to its diuretic effect.
Acetazolamide can interact with various other medications, potentially altering their effectiveness or increasing the risk of side effects. For example, concomitant use with high-dose aspirin can lead to severe adverse effects, including metabolic acidosis, lethargy, or even coma. It can also interact with other diuretics, lithium, phenytoin, primidone, and certain diabetes medications. Informing your doctor about all medications, including over-the-counter drugs and supplements, is important to prevent adverse interactions.
Acetazolamide is not suitable for everyone. It is contraindicated in individuals with severe kidney or liver disease. It should also be avoided in those with low blood sodium or potassium levels, or hyperchloremic acidosis. Patients with a history of severe allergic reactions to sulfonamide drugs should use acetazolamide with caution. Regular monitoring of blood and urine tests, including electrolyte levels, is often recommended to check for unwanted effects and ensure the medication is working properly.