• Glaucoma

Methazolamide Generic Name & Formulations

General Description

Methazolamide 25mg, 50mg; tabs.

Pharmacological Class

Carbonic anhydrase inhibitor.

How Supplied

Contact supplier

Methazolamide Indications


Ocular conditions where lowering intraocular pressure would be of therapeutic benefit (eg, chronic open-angle glaucoma, secondary glaucoma, pre-op in acute angle-closure glaucoma).

Methazolamide Dosage and Administration


50–100mg 2–3 times daily.


Not recommended.

Methazolamide Contraindications


Hypokalemia. Hyponatremia. Severe renal, hepatic, or adrenocortical impairment. Hyperchloremic acidosis. Cirrhosis. Long-term use in angle-closure glaucoma.

Methazolamide Boxed Warnings

Not Applicable

Methazolamide Warnings/Precautions


Sulfonamide allergy. Respiratory impairment (eg, pulmonary obstruction or emphysema). Do baseline CBC and platelet counts before starting and during therapy. Monitor serum electrolytes periodically. Pregnancy (Cat.C). Nursing mothers: not recommended.


  • Severe reactions to sulfonamides may occur including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. 

  • Discontinue use if hypersensitivity or other serious reactions occur.

  • Use caution for patients receiving high-dose aspirin and methazolamide concomitantly.

  • Upon initial administration of methazolamide, potassium excretion is increased which could result in hepatic coma in patients with cirrhosis or hepatic insufficiency.

  • Use caution in patients with pulmonary obstruction or emphysema because methazolamide may precipitate or aggravate acidosis.

Pregnancy Considerations

Teratogenic effects

  • Pregnancy Category C: No adequate and well controlled studies in pregnant women. Only use during pregnancy if the potential benefit justifies the potential risk to the fetus.

Nursing Mother Considerations

  • Not known whether this drug is excreted in human milk.
  • Due to the potential for serious adverse reactions in nursing infants, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother.

Pediatric Considerations

Safety and effectiveness of methazolamide in children have not been established.

Methazolamide Pharmacokinetics


Renal. Half-life: ~14 hours.

Methazolamide Interactions


May inhibit renal excretion of basic drugs and promote excretion of acidic drugs. Caution with high-dose aspirin; may increase salicylate toxicity. Caution with corticosteroids; may develop hypokalemia.

Methazolamide Adverse Reactions

Adverse Reactions

Paresthesias, tinnitus, fatigue, malaise, anorexia, GI upset, dysguesia, drowsiness, confusion, metabolic acidosis, electrolyte imbalance, transient myopia; hepatic insufficiency, blood dyscrasias, anaphylaxis, urticaria, melena, hematuria, glycosuria, flaccid paralysis, photosensitivity, convulsions; rare: crystalluria, renal calculi.

Methazolamide Clinical Trials

See Literature

Methazolamide Note


Formerly known under the brand name Neptazane.

Methazolamide Patient Counseling

Patient Counseling

  • Use caution for patients receiving high-dose aspirin and methazolamide concomitantly.

  • Advise patients to detect adverse reactions common to all sulfonamide derivatives, and discontinue methazolamide if it develops and institute appropriate therapy.