Acetazolamide (Tablets) Instructions for Use

ATC Code

S01EC01 (Acetazolamide)

Active Substance

Acetazolamide (Rec.INN registered by WHO)

Clinical-Pharmacological Group

Diuretic. Carbonic anhydrase inhibitor

Pharmacotherapeutic Group

Diuretic agent

Pharmacological Action

A diuretic with a weakly expressed diuretic effect. It inhibits the enzyme carbonic anhydrase in the proximal convoluted tubule of the nephron.

It increases the urinary excretion of sodium, potassium, and bicarbonate ions, does not affect the excretion of chloride ions; it causes an increase in urine pH.

With prolonged and/or frequent use, it can cause metabolic acidosis. It reduces intraocular pressure. It decreases the production of cerebrospinal fluid.

Pharmacokinetics

After oral administration, Acetazolamide is well absorbed from the gastrointestinal tract.

After a dose of 500 mg, the C_max of the active substance is 12-27 µg/ml and is achieved in 1-3 hours.

A detectable concentration of acetazolamide in plasma persists for 24 hours after administration.

It is distributed mainly in erythrocytes, kidneys, muscles, eye tissues, and the central nervous system.

It binds to plasma proteins to a high degree. It crosses the placental barrier.

Acetazolamide is not biotransformed in the body.

It is excreted by the kidneys unchanged. About 90% of the dose is excreted in the urine within 24 hours.

Indications

Edematous syndrome, especially in combination with alkalosis, in chronic heart and cardiopulmonary failure (as part of complex therapy); increased intracranial pressure; primary and secondary glaucoma, acute attack of glaucoma; minor epileptic seizures.

ICD codes

Dosage Regimen

For edematous syndrome, administer 250 mg once or twice daily. Limit treatment courses to 2-4 days. Separate courses with drug-free intervals of several days.

For epilepsy, administer 250 mg three to four times daily.

For an acute glaucoma attack, use an initial dose of 250-500 mg. Follow with a maintenance dose of 250 mg every 6 hours.

After initial control, gradually reduce the dose to the lowest effective level for long-term management.

In pediatric patients, adjust the dose based on the child’s age and body weight. Do not exceed recommended pediatric dosages.

For all indications, do not exceed a maximum daily dose of 1 gram.

For chronic open-angle glaucoma, administer 250 mg once or twice daily or 500 mg in a sustained-release form twice daily.

For benign intracranial hypertension), administer 250 mg twice daily.

Administer tablets with a full glass of water. Take with or after meals to minimize gastrointestinal upset.

Monitor serum electrolytes, particularly potassium and bicarbonate, during therapy. Avoid continuous administration for more than 5 days without monitoring due to the risk of metabolic acidosis.

Adverse Reactions

Possible hypokalemia, muscle weakness, convulsions, skin redness, loss of appetite, metabolic acidosis, skin itching.

With long-term use cases of nephrolithiasis, transient hematuria and glucosuria, hemolytic anemia, leukopenia, agranulocytosis, paresthesia, disorientation have been described.

Contraindications

Acute renal failure, severe liver function disorders, hypokalemia, metabolic acidosis, hypocorticism, diabetes mellitus, first trimester of pregnancy.

Use in Pregnancy and Lactation

Acetazolamide is contraindicated in the first trimester; in the second and third trimesters, it is used with caution and only in cases where the potential benefit to the mother outweighs the potential risk to the fetus.

Acetazolamide is excreted in small amounts in breast milk, so if it is necessary to use during lactation, breastfeeding should be discontinued.

Use in Hepatic Impairment

Contraindicated: severe liver function disorders,

Use in Renal Impairment

Contraindicated: acute renal failure. Use with caution in patients with impaired renal function.

Geriatric Use

Use with caution in elderly patients.

Special Precautions

Acetazolamide should not be used for more than 5 days in a row due to the increased risk of developing metabolic acidosis.

Use with caution in elderly patients and/or patients with impaired renal function due to an increased risk of developing metabolic acidosis. Acetazolamide may enhance the manifestations of osteomalacia caused by anticonvulsant drugs, increase the risk of manifestation of toxic effects of salicylates, digitalis preparations, carbamazepine, ephedrine, non-depolarizing muscle relaxants. At the same time, Acetazolamide increases the clinical efficacy of insulin and oral hypoglycemic agents.

Drug Interactions

With simultaneous use with anticholinesterase drugs, muscle weakness increases in patients with myasthenia gravis.

With simultaneous use, the risk of developing toxic effects of salicylates, digitalis preparations, carbamazepine, ephedrine, non-depolarizing muscle relaxants increases.

With simultaneous use with diuretics, theophylline, the diuretic effect is potentiated.

With simultaneous use with lithium preparations, an increase in the excretion of lithium in the urine is possible. A case of lithium intoxication (with a significant increase in its plasma concentration) after therapy with acetazolamide for 1 month has been described.

Ammonium chloride causes acidosis and weakens the effect of acetazolamide (should not be used simultaneously).

With simultaneous use with acetazolamide, the clinical efficacy of insulin and oral hypoglycemic agents increases.

With simultaneous use with primidone, a decrease in the concentration of primidone in the blood serum, a decrease in its anticonvulsant action, and pronounced osteomalacia are possible; with phenytoin, phenobarbital – pronounced osteomalacia.

There are reports that with simultaneous use, the concentration of cyclosporine in the blood plasma increases significantly and rapidly, which may be accompanied by a toxic effect on the kidneys.

Storage Conditions

Store at 2°C (36°F) to 25°C (77°F). Keep in original packaging, protected from light. Keep out of reach of children.

Dispensing Status

Rx Only

Important Safety Information

This information is for educational purposes only and does not replace professional medical advice. Always consult your doctor before use. Dosage and side effects may vary. Use only as prescribed.