Methazolamide is used only in the adjunctive treatment of open-angle (noncongestive, chronic simple) or secondary glaucoma and for short-term preoperative therapy in angle-closure (obstructive, narrow-angle) glaucoma when delay of surgery is desired in order to lower intraocular pressure.
Dosage and Administration
Methazolamide is administered orally.
Dosage of methazolamide must be adjusted according to the patient's requirements and response. The usual adult dosage of methazolamide is 50-100 mg 2 or 3 times daily.
Methazolamide shares the pharmacologic actions and toxic potentials of the carbonic anhydrase inhibitors, and the usual precautions of carbonic anhydrase inhibitor therapy should be observed. The manufacturers state that methazolamide is contraindicated in patients with severe or absolute glaucoma.
Methazolamide is absorbed more slowly from the GI tract and disappears more slowly from the plasma than does acetazolamide.
Methazolamide is distributed into plasma, erythrocytes, extracellular fluid, bile, the aqueous humor of the eye, and CSF. The drug crosses the placenta in unknown quantities. It is not known whether methazolamide is distributed into the milk of nursing women.
Methazolamide is partially metabolized in the liver. About 20-30% of a dose is excreted in urine as substances with carbonic anhydrase inhibitor activity. The fate of the remainder of the dose has not been determined.