Diamox

Diamox (acetazolamide) is a carbonic anhydrase inhibitor prescription medication primarily indicated for the treatment of open-angle glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma. It is also a well-established prophylactic and therapeutic agent for acute mountain sickness (AMS), aiding in acclimatization at high altitudes. Its mechanism of action reduces intraocular pressure and corrects metabolic alkalosis, making it a versatile tool in specific neurological and respiratory conditions as well.

Features

• Active Ingredient: Acetazolamide
• Drug Class: Carbonic anhydrase inhibitor
• Available Forms: Oral tablets (125 mg, 250 mg) and extended-release capsules (500 mg)
• Prescription Status: Requires a prescription from a licensed healthcare provider
• Mechanism: Inhibits the enzyme carbonic anhydrase, reducing aqueous humor secretion in the eye and promoting diuresis and metabolic acidosis

Benefits

• Effectively lowers elevated intraocular pressure (IOP), helping to prevent optic nerve damage and preserve vision in glaucoma patients.
• Significantly reduces the incidence and severity of symptoms associated with acute mountain sickness, such as headache, nausea, and dizziness, when used prophylactically.
• Can be used as an adjunctive therapy for certain types of seizures, particularly absence seizures.
• Promotes diuresis in cases of heart failure when other therapies are unsuitable or insufficient.
• Aids in the correction of metabolic alkalosis by increasing renal excretion of bicarbonate.
• Provides a non-surgical option for managing pressure-related ophthalmic conditions.

Common use

Diamox is commonly prescribed for the management of various forms of glaucoma, including chronic open-angle glaucoma and secondary glaucoma. It is a standard prophylactic medication for individuals ascending to high altitudes (>3,000 meters or ~10,000 feet) rapidly, such as mountain climbers, skiers, and hikers. It is also used as an adjunctive treatment for certain seizure disorders (e.g., absence seizures, myoclonic seizures) and for the reduction of edema due to congestive heart failure. Off-label uses may include the treatment of idiopathic intracranial hypertension (pseudotumor cerebri) and central sleep apnea.

Dosage and direction

Dosage is highly individualized and must be determined by a physician based on the condition being treated, patient response, and renal function.

• Glaucoma:
  • Adults: 250 mg to 1 gram per 24 hours, usually in divided doses (e.g., 125 mg to 250 mg two to four times daily). The sustained-release capsule (500 mg) may be taken twice daily.
  • Children: 8 to 30 mg/kg per 24 hours in divided doses every 6 to 8 hours.
• Altitude Sickness Prophylaxis:
  • Adults: 125 mg twice daily, starting 24 to 48 hours before ascent and continuing for 48 hours after reaching the target altitude or longer if symptoms persist.
  • Children: Not typically recommended; consult a pediatric specialist.
• Edema in Heart Failure:
  • Adults: 250 mg to 375 mg once daily in the morning for optimal diuretic effect.
• Seizures:
  • Adults: 8 to 30 mg/kg per day in divided doses.
  • Children: 8 to 30 mg/kg per day in divided doses.

Direction: Tablets should be swallowed whole with a full glass of water. Sustained-release capsules should not be crushed or chewed. It is best taken with or after food to minimize gastrointestinal upset. Adherence to the prescribed schedule is critical for efficacy.

Precautions

Patients should inform their doctor of any history of kidney disease, liver disease, adrenal gland failure, electrolyte imbalances (e.g., low sodium, potassium), diabetes, gout, or chronic respiratory conditions (e.g., COPD, emphysema). Diamox can cause photosensitivity; use sunscreen and protective clothing when outdoors. It may cause drowsiness, dizziness, or blurred vision; patients should exercise caution before driving or operating machinery until they know how the drug affects them. Regular monitoring of electrolytes (especially potassium and bicarbonate), complete blood counts, and renal function is advised during long-term therapy. This medication is a sulfonamide and should be used with caution in patients with sulfa allergies, though cross-reactivity is not absolute.

Contraindications

Diamox is contraindicated in patients with:

• Hypersensitivity to acetazolamide or any sulfonamides.
• Significant renal impairment (e.g., renal failure, hyperchloremic acidosis).
• Severe hepatic disease or cirrhosis.
• Adrenocortical insufficiency, hypokalemia, hyponatremia.
• Long-term use in chronic non-congestive angle-closure glaucoma.

Possible side effect

Common side effects are often dose-related and may include:

• Paresthesia (tingling/numbness in fingers, toes, and around the mouth)
• Polyuria (increased urination) and thirst
• Loss of appetite, altered taste (particularly a metallic taste when drinking carbonated beverages)
• Nausea, vomiting, diarrhea
• Drowsiness, fatigue, confusion
• Photosensitivity

Serious side effects requiring immediate medical attention are rare but include:

• Signs of electrolyte imbalance (muscle cramps/weakness, irregular heartbeat, seizures)
• Signs of kidney problems (painful urination, blood in urine, lower back pain, change in urine amount)
• Signs of liver problems (persistent nausea/vomiting, severe stomach/abdominal pain, dark urine, yellowing eyes/skin)
• Signs of a severe allergic reaction (rash, itching/swelling, severe dizziness, trouble breathing)
• Stevens-Johnson syndrome (blistering, peeling skin rash)

Drug interaction

Diamox can interact with several medications, potentially altering their effects or increasing the risk of side effects.

• Other Diuretics: May potentiate effects and increase the risk of severe dehydration and electrolyte depletion.
• Salicylates (e.g., Aspirin, high doses): Increase the risk of central nervous system toxicity, including lethargy and metabolic acidosis.
• Anticonvulsants (e.g., Phenytoin, Primidone): Acetazolamide may alter their levels; monitoring is recommended.
• Methenamine: Diamox may reduce its effectiveness.
• Cyclosporine: Acetazolamide may increase cyclosporine levels and risk of toxicity.
• Sodium Bicarbonate: May counteract the metabolic acidosis induced by Diamox.
• Amphetamines, Quinidine, Procainamide: Acetazolamide alkalinizes the urine, which can decrease the renal excretion of these drugs, potentially increasing their blood levels and toxicity.
• Hypoglycemic Agents: May potentiate their effect; blood glucose should be monitored.

Patients must provide their doctor with a complete list of all medications, including prescription, over-the-counter, and herbal products.

Missed dose

If a dose is missed, it should be taken as soon as it is remembered. However, if it is almost time for the next scheduled dose, the missed dose should be skipped. Patients should never take a double dose to make up for a missed one, as this increases the risk of side effects. Maintaining a consistent dosing schedule is important for the drug’s effectiveness, especially in managing glaucoma.

Overdose

Symptoms of an acetazolamide overdose are primarily an extension of its side effects and may include severe electrolyte imbalances (leading to muscle spasms, weakness, cardiac arrhythmias), severe drowsiness, confusion, tinnitus, gastrointestinal distress (nausea, vomiting), and respiratory depression. In case of suspected overdose, immediate medical attention should be sought. Treatment is supportive and symptomatic, focusing on correcting electrolyte and acid-base imbalances. There is no specific antidote.

Storage

Store Diamox tablets and capsules at room temperature (15°-30°C or 59°-86°F) in a tightly closed container. The medication must be kept away from light, excess moisture (do not store in a bathroom), and heat. Keep all medications out of the reach of children and pets. Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard any expired or no-longer-needed medication through a medicine take-back program.

Disclaimer

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition or before starting any new treatment. Never disregard professional medical advice or delay in seeking it because of something you have read here. The content has not been evaluated by all regulatory agencies.

Reviews

• “As an ophthalmologist, I’ve prescribed Diamox for decades. It remains a cornerstone for managing acute glaucoma presentations and is invaluable for bridging patients to definitive surgical treatment. The side effect profile is manageable in most, and its efficacy in lowering IOP is reliable.” – Dr. E. Lawson, MD
• “Used it for a high-altitude trek to Everest Base Camp. Started taking it 36 hours before the flight. Experienced the expected tingling and frequent urination, but had zero symptoms of AMS while others in my group struggled significantly. A vital tool for safe ascent.” – Mark T., Mountaineer
• “Prescribed for IIH. The side effects were challenging at first (fatigue, taste changes), but they subsided after a few weeks. The reduction in my intracranial pressure and debilitating headaches has been life-changing. Requires careful monitoring by my neurologist.” – Sarah J., Patient
• “The metabolic acidosis it induces can be a useful therapeutic effect in specific ICU scenarios, such as metabolic alkalosis refractory to other treatments. It’s a drug with a narrow but powerful set of indications.” – Dr. A. Chen, Critical Care Specialist