Methazolamide 25 mg Tablet, 100-count
🆔 Identity & classification
Where does this data come from?
🏷️ RxNorm drug class
This medicine belongs to the Carbonic anhydrase inhibitors class.
Where does this data come from?
🏭 Manufacturer & labeler
Where does this data come from?
🩺 Clinical
- It's reducing the pressure inside your eye. Your eye constantly makes a fluid called aqueous humor, and methazolamide slows down how much of that fluid is produced. Less fluid mean...
- What is methazolamide actually doing for my eyes?
- The most common one people notice is a tingling or 'pins and needles' feeling in their hands and feet — it can be a little odd but it's well known with this type of drug. You might...
- What side effects should I actually expect when I start taking it?
Patient education
Supplement & herbal interactions
Some supplements/herbs that may interact with Methazolamide — tap one for details:
Methazolamide may be associated with lower levels of 7 nutrients — worth a chat with your pharmacist, not a cause for alarm.
Where does this data come from?
Ask a licensed pharmacist directly — free, answered by our team.
💊 What it looks like
Where does this data come from?
🧪 Inactive Ingredients / Excipients
Inactive ingredients, also called excipients, are components of the drug product other than the active ingredient. They may include fillers, dyes, coatings, preservatives, flavors, or other formulation ingredients.
Where does this data come from?
IACT rows and label-wide narrative are kept separate; availability and product-level specificity depend on the submitted label.Inactive ingredient FAQ
Are inactive ingredients the same for every manufacturer?
Why might an inactive ingredient be missing?
Can inactive ingredients matter?
💲 Pricing
A drug doesn't have one price. Each row is a different public payment system, and none is what you'd pay at the counter — that depends on your insurance. The ⓘ on each row explains what it measures.
| Price system | Per ea | Per package |
|---|---|---|
| Retail pharmacies payNADAC · weekly | $0.628 | $62.75 / 100 tablets |
| Medicaid paysCMS SDUD · 12 mo | No recent Medicaid claims on file for this NDC — rare and low-volume NDCs are suppressed in the public data. | |
| Medicare drug plans payPart D · Q2 2026 | $1.59 | $159.26 / 100 tablets |
Where does this data come from?
🔁 Therapeutic equivalents
| Product | Labeler | Pack | NADAC/unit | TE | Status | Price vs. this |
|---|---|---|---|---|---|---|
| methazolamide 25 mg 00574-0790-01 | Padagis | 100 tablets | $0.627 | AB | Availability likely | — |
| Methazolamide 25 mg 62559-0240-01 | ANI | 100 tablets | $0.627 | AB | Availability likely | — |
| Methazolamide 25 mgthis 68094-0908-50 | Precision | 100 tablets | $0.627 | AB | Availability likely | — |
| Methazolamide 25 mg 72603-0166-01 | NorthStar | 100 tablets | $0.627 | AB | Availability likely | — |
| Methazolamide 25 mg 24208-0022-01 | Bausch | 1000 tablets | — | AB | FDA listed | — |
| Methazolamide 25 mg 27241-0246-01 | Ajanta | 100 tablets | — | AB | FDA listed | — |
| Methazolamide 25 mg 42571-0239-05 | Micro | 500 tablets | — | AB | FDA listed | — |
| Methazolamide 25 mg 51407-0026-01 | Golden | 100 tablets | — | AB | FDA listed | — |
| Methazolamide 25 mg 63629-1986-01 | Bryant | 100 tablets | — | AB | FDA listed | — |
| Methazolamide 25 mg 72162-1754-01 | Bryant | 100 tablets | — | AB | FDA listed | — |
Where does this data come from?
⏳ Availability & generic status
This product is an FDA-approved generic. Other versions of the same drug are listed under Therapeutic equivalents, least expensive first.
Where does this data come from?
📊 Medicare Part D spend CMS · PART D · 2026 (Q1)
🔬 Reported adverse events (FAERS)
Top reported reactions
Age at onset
Reporter sex
Serious outcomes
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📦 Packaging — all sizes for this product
| Package NDC | Description | Marketing start | Status |
|---|---|---|---|
| 68094-0908-50 You're viewing this | 100 TABLET in 1 BOTTLE (68094-908-50) | 2023-11-30 | Active |
📄 Full prescribing information FDA SPL
🎯 Indications and Usage ▾
INDICATIONS AND USAGE Methazolamide Tablets, USP is indicated in the treatment of ocular conditions where lowering intraocular pressure is likely to be of therapeutic benefit, such as chronic open-angle glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where lowering the intraocular pressure is desired before surgery.
⏱️ Dosage and Administration ▾
DOSAGE AND ADMINISTRATION The effective therapeutic dose administered varies from 50 mg to 100 mg two or three times daily. The drug may be used concomitantly with miotic and osmotic agents.
⛔ Contraindications ▾
CONTRAINDICATIONS Methazolamide therapy is contraindicated in situations in which sodium and/or potassium serum levels are depressed, in cases of marked kidney or liver disease or dysfunction, in adrenal gland failure, and in hyperchloremic acidosis. In patients with cirrhosis, use may precipitate the development of hepatic encephalopathy. Long-term administration of methazolamide is contraindicated in patients with angle-closure glaucoma, since organic closure of the angle may occur in spite of lowered intraocular pressure.
⚠️ Warnings ▾
WARNINGS Fatalities have occurred, although rarely, due to severe reactions to sulfonamides including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias. Hypersensitivity reactions may recur when a sulfonamide is readministered, irrespective of the route of administration. If hypersensitivity or other serious reactions occur, the use of this drug should be discontinued.
Caution is advised for patients receiving high-dose aspirin and methazolamide concomitantly, as anorexia, tachypnea, lethargy, coma, and death have been reported with concomitant use of high-dose aspirin and carbonic anhydrase inhibitors.
🤒 Adverse Reactions ▾
ADVERSE REACTIONS Adverse reactions, occurring most often early in therapy, include paresthesias, particularly a "tingling" feeling in the extremities; hearing dysfunction or tinnitus; fatigue; malaise; loss of appetite; taste alteration; gastrointestinal disturbances such as nausea, vomiting, and diarrhea; polyuria; and occasional instances of drowsiness and confusion. Metabolic acidosis and electrolyte imbalance may occur. Transient myopia has been reported.
This condition invariably subsides upon diminution or discontinuance of the medication. Other occasional adverse reactions include urticaria, melena, hematuria, glycosuria, hepatic insufficiency, flaccid paralysis, photosensitivity, convulsions, and, rarely, crystalluria and renal calculi. Also see PRECAUTIONS: Information for Patients for possible reactions common to sulfonamide derivatives.
Fatalities have occurred, although rarely, due to severe reactions to sulfonamides including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias (see WARNINGS ).
🔄 Drug Interactions ▾
Drug Interactions Methazolamide should be used with caution in patients on steroid therapy because of the potential for developing hypokalemia. Caution is advised for patients receiving high-dose aspirin and methazolamide concomitantly, as anorexia, tachypnea, lethargy, coma and death have been reported with concomitant use of high-dose aspirin and carbonic anhydrase inhibitors (see WARNINGS ).
🤰 Pregnancy ▾
Pregnancy Teratogenic effects Methazolamide has been shown to be teratogenic (skeletal anomalies) in rats when given in doses approximately 40 times the human dose. There are no adequate and well controlled studies in pregnant women. Methazolamide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
🧒 Pediatric Use ▾
Pediatric Use The safety and effectiveness of methazolamide in pediatric patients have not been established.
🆘 Overdosage ▾
OVERDOSAGE No data are available regarding methazolamide overdosage in humans as no cases of acute poisoning with this drug have been reported. Animal data suggest that even a high dose of methazolamide is nontoxic. No specific antidote is known.
Treatment should be symptomatic and supportive. Electrolyte imbalance, development of an acidotic state, and central nervous system effects might be expected to occur. Serum electrolyte levels (particularly potassium) and blood pH levels should be monitored.
Supportive measures may be required to restore electrolyte and pH balance.
🧬 Clinical Pharmacology ▾
CLINICAL PHARMACOLOGY Methazolamide is a potent inhibitor of carbonic anhydrase. Methazolamide is well absorbed from the gastrointestinal tract. Peak plasma concentrations are observed 1 to 2 hours after dosing.
In a multiple-dose, pharmacokinetic study, administration of methazolamide 25 mg BID, 50 mg BID, and 100 mg BID demonstrated a linear relationship between plasma methazolamide levels and methazolamide dose. Peak plasma concentrations (Cmax) for the 25 mg, 50 mg and 100 mg BID regimens were 2.5 mcg/mL, 5.1 mcg/mL, and 10.7 mcg/mL, respectively. The area under the plasma concentration-time curves (AUC) were 1130 mcg.min/mL, 2571 mcg.min/mL, and 5418 mcg.min/mL for the 25 mg, 50 mg, and 100 mg dosage regimens, respectively.
Methazolamide is distributed throughout the body including the plasma, cerebrospinal fluid, aqueous humor of the eye, red blood cells, bile and extracellular fluid. The mean apparent volume of distribution (V area /F) ranges from 17 L to 23 L. Approximately 55% is bound to plasma proteins.
The steady-state methazolamide red blood cell:plasma ratio varies with dose and were found to be 27:1, 16:1, and 10:1 following the administration of methazolamide 25 mg BID, 50 mg BID, and 100 mg BID, respectively. The mean steady-state plasma elimination half-life for methazolamide is approximately 14 hours. At steady-state, approximately 25% of the dose is recovered unchanged in the urine over the dosing interval.
Renal clearance accounts for 20% to 25% of the total clearance of drug. After repeated BID- lid dosing, methazolamide accumulates to steady-state concentrations in 7 days. Methazolamide's inhibitory action on carbonic anhydrase decreases the secretion of aqueous humor and results in a decrease in intraocular pressure.
The onset of the decrease in intraocular pressure generally occurs within 2 to 4 hours, has a peak effect in 6 to 8 hours and a total duration of 10 to 18 hours. Methazolamide is a sulfonamide derivative; however, it does not have any clinically significant antimicrobial properties. Although methazolamide achieves a high concentration in the cerebrospinal fluid, it is not considered an effective anticonvulsant.
Methazolamide has a weak and transient diuretic effect; therefore, use results in an increase in urinary volume, with excretion of sodium, potassium, and chloride. The drug should not be used as a diuretic. Inhibition of renal bicarbonate reabsorption produces an alkaline urine.
Plasma bicarbonate decreases, and a relative, transient metabolic acidosis may occur due to a disequilibrium in carbon dioxide transport in the red blood cell. Urinary citrate excretion is decreased by approximately 40% after doses of 100 mg every 8 hours. Uric acid output has been shown to decrease 36% in the first 24 hour period.
📦 How Supplied / Storage and Handling ▾
HOW SUPPLIED Methazolamide Tablets USP, 25 mg are white to off white, uncoated, round, biconvex tablets debossed with '25' on one side and 'ZEN' on other side and are supplied in bottles of 100, NDC 68094-908-50. Methazolamide Tablets USP, 50 mg are white to off white, uncoated, round, biconvex tablets debossed with '5 and 0' on either side of the break line one side and 'ZEN' on other side and are supplied in bottles of 100, NDC 68094-808-50. Store at 20°C to 25°C (68°F to 77°F). [See USP Controlled Room Temperature].
Dispense in a tight container as defined in the USP, with a child-resistant closure (as required).
📦 Storage and Handling ▾
Store at 20°C to 25°C (68°F to 77°F). [See USP Controlled Room Temperature]. Dispense in a tight container as defined in the USP, with a child-resistant closure (as required).
📋 Description ▾
DESCRIPTION Methazolamide, a sulfonamide derivative, is a white or faintly yellow, crystalline powder, soluble in dimethyl formamide, slightly soluble in acetone, very slightly soluble in water and alcohol. The chemical name for methazolamide is: Acetamide, N-[5-(aminosulfonyl)-3-methyl-1,3,4-thiadiazol-2(3H)-ylidene]- and it has the following structural formula: C5H8N4O3S2 236.26 Each tablet, for oral administration, contains 25 mg or 50 mg methazolamide. In addition, each tablet contains the following inactive ingredients: colloidal silicon dioxide, croscarmellose sodium, dibasic calcium phosphate dihydrate, magnesium stearate, microcrystalline cellulose, and isopropyl alcohol. lsopropyl alcohol is removed during manufacturing process Chemical Structure
💬 Information for Patients ▾
Information for Patients Adverse reactions common to all sulfonamide derivatives may occur: anaphylaxis, fever, rash (including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis), crystalluria, renal calculus, bone marrow depression, thrombocytopenic purpura, hemolytic anemia, leukopenia, pancytopenia, and agranulocytosis. Precaution is advised for early detection of such reactions, and the drug should be discontinued and appropriate therapy instituted. Caution is advised for patients receiving high-dose aspirin and methazolamide concomitantly.