methazolamide (Rx)

Brand and Other Names:Neptazane (DSC)
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

tablet

  • 25mg
  • 50mg

Glaucoma

50-100 mg PO BID/TID

Other Indications & Uses

Off-label: Altitude sickness

Safety and effecacy not established

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Interactions

Interaction Checker

and methazolamide

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     activity indicator 
    No Interactions Found
    Interactions Found

    Contraindicated

      Serious - Use Alternative

        Significant - Monitor Closely

          Minor

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             activity indicator 

            Contraindicated (0)

              Serious - Use Alternative (0)

                Monitor Closely (17)

                • amantadine

                  methazolamide will decrease the level or effect of amantadine by Other (see comment). Modify Therapy/Monitor Closely. Excretion rate of amantadine increases rapidly when urine is acidic, administration of urine acidifying drugs may increase elimination of amantadine from the body. Monitor for efficacy of amantadine.

                • aspirin

                  methazolamide, aspirin. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • aspirin rectal

                  methazolamide, aspirin rectal. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • aspirin/citric acid/sodium bicarbonate

                  methazolamide, aspirin/citric acid/sodium bicarbonate. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • balsalazide

                  methazolamide, balsalazide. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • choline magnesium trisalicylate

                  methazolamide, choline magnesium trisalicylate. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • dichlorphenamide

                  dichlorphenamide and methazolamide both decrease serum potassium. Use Caution/Monitor.

                  dichlorphenamide, methazolamide. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.

                • diflunisal

                  methazolamide, diflunisal. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • lisdexamfetamine

                  methazolamide will increase the level or effect of lisdexamfetamine by passive renal tubular reabsorption - basic urine. Use Caution/Monitor.

                • mesalamine

                  methazolamide, mesalamine. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • metformin

                  methazolamide increases toxicity of metformin by Other (see comment). Use Caution/Monitor. Comment: Decreases serum bicarbonate and induce non-anion gap, hyperchloremic metabolic acidosis.

                • salicylates (non-asa)

                  methazolamide, salicylates (non-asa). Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • salsalate

                  methazolamide, salsalate. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • sulfasalazine

                  methazolamide, sulfasalazine. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                • tobramycin inhaled

                  tobramycin inhaled and methazolamide both increase nephrotoxicity and/or ototoxicity. Modify Therapy/Monitor Closely. Avoid concurrent or sequential use to decrease risk for ototoxicity

                • topiramate

                  topiramate, methazolamide. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of kidney stone formation.

                • willow bark

                  methazolamide, willow bark. Either increases levels of the other by Other (see comment). Use Caution/Monitor. Comment: Carbonic anhydrase inhibitors (CAIs) and salicylates inhibit each other's renal tubular secretion, resulting in increased plasma levels. CAIs also shift salicylates from plasma to the CNS, leading to potential neurotoxicity.

                Minor (10)

                • amobarbital

                  methazolamide, amobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • butabarbital

                  methazolamide, butabarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • butalbital

                  methazolamide, butalbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • ethotoin

                  methazolamide, ethotoin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • fosphenytoin

                  methazolamide, fosphenytoin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • pentobarbital

                  methazolamide, pentobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • phenobarbital

                  methazolamide, phenobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • phenytoin

                  methazolamide, phenytoin. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • primidone

                  methazolamide, primidone. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

                • secobarbital

                  methazolamide, secobarbital. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Increased risk of anticonvulsant induced osteomalacia.

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                Adverse Effects

                >10%

                Drowsiness

                Paresthesias

                Anorexia

                Nausea

                Vomiting

                Frequency Not Defined

                Sulfonamide-type rxns

                Acidosis

                Electrolyte imbalance

                Glycosuria

                Hematuria

                Thrombocytopenia

                Hepatic dysfunction

                Tinnitus

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                Warnings

                Contraindications

                Hypokalemia, hyponatremia, hyperchloremic acidosis, cirrhosis, severe liver or renal impairment, adrenal gland failure

                Cautions

                COPD, emphysema, concomitant high-dose aspirin or steroid therapy, or hepatic insufficiency

                ADRs common to sulfonamide derivatives

                Stevens-Johnson syndrome and toxic epidermal necrolysis may occur

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                Pregnancy & Lactation

                Pregnancy Category: C

                Lactation: not known if crosses in to breast milk, avoid

                Pregnancy Categories

                A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

                B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

                C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

                D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

                X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

                NA: Information not available.

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                Pharmacology

                Mechanism of Action

                Carbonic anhydrase inhibitor, decr rate of aqueous humor formation and decreased IOP

                Pharmacokinetics

                Half-life: 14 d

                Onset: 2-4 hr

                Max Effect: 6-8 hr

                Duration: 10-18 hr

                Bioavailability: absorbed more slowly than acetazolamide

                Excretion: urine 15%

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                Images

                BRAND FORM. UNIT PRICE PILL IMAGE
                methazolamide oral
                -
                25 mg tablet
                methazolamide oral
                -
                50 mg tablet
                methazolamide oral
                -
                25 mg tablet
                methazolamide oral
                -
                50 mg tablet
                methazolamide oral
                -
                50 mg tablet
                methazolamide oral
                -
                25 mg tablet

                Copyright © 2010 First DataBank, Inc.

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                Patient Handout

                Patient Education
                methazolamide oral

                METHAZOLAMIDE - ORAL

                (METH-a-ZOL-a-mide)

                COMMON BRAND NAME(S): Neptazane

                USES: This medication is used to treat high pressure inside the eye due to certain types of glaucoma. Lowering high pressure inside the eye helps to prevent blindness, vision loss, and nerve damage. Methazolamide belongs to a class of drugs known as carbonic anhydrase inhibitors. It works by decreasing the production of fluid inside the eye.

                HOW TO USE: Take this medication by mouth as directed by your doctor, usually 2 or 3 times a day. This medication may be taken with food if stomach upset occurs. To reduce your risk of certain side effects (kidney stones), drink plenty of fluids unless otherwise directed by your doctor.The dosage is based on your medical condition and response to treatment.Use this medication regularly to get the most benefit from it. To help you remember, take it at the same times each day. Keep taking this medication even if you feel well. Most people with glaucoma or high pressure in the eye(s) do not feel sick.

                SIDE EFFECTS: Nausea, loss of appetite, change in taste, vomiting, diarrhea, frequent urination, dizziness, drowsiness, or tiredness may occur as your body adjusts to the medication. If any of these effects last or get worse, tell your doctor or pharmacist promptly.Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.Tell your doctor right away if you have any serious side effects, such as: signs of kidney stones (such as painful urination, fever, chills, pink/bloody urine), signs of infection (such as sore throat that doesn't go away, fever, chills), easy bleeding/bruising, numbness or tingling of hands/feet, ringing in the ears.Get medical help right away if you have any very serious side effects, such as: nausea/vomiting that doesn't stop, loss of appetite, stomach/abdominal pain, yellowing of eyes/skin, dark urine, confusion, fast/pounding heartbeat, seizures.A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, such as: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.In the US -Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

                PRECAUTIONS: Before taking methazolamide, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.Before using this medication, tell your doctor or pharmacist your medical history, especially of: adrenal gland problems (such as Addison's disease), liver disease (such as cirrhosis), breathing problems (such as chronic obstructive pulmonary disease-COPD, emphysema, lung infection), diabetes, gout, kidney problems (such as history of kidney stones), untreated mineral imbalance (such as low sodium/potassium, hyperchloremic acidosis), overactive thyroid (hyperthyroidism).This drug may make you dizzy or drowsy. Alcohol or marijuana (cannabis) can make you more dizzy or drowsy. Do not drive, use machinery, or do anything that needs alertness until you can do it safely. Limit alcoholic beverages. Talk to your doctor if you are using marijuana (cannabis).This medication may make you more sensitive to the sun. Limit your time in the sun. Avoid tanning booths and sunlamps. Use sunscreen and wear protective clothing when outdoors. Tell your doctor right away if you get sunburned or have skin blisters/redness.Before having surgery, tell your doctor or dentist about all the products you use (such as prescription drugs, nonprescription drugs, and herbal products).During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.It is unknown if this medication passes into breast milk. Consult your doctor before breast-feeding.

                DRUG INTERACTIONS: Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (such as prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.Some products that may interact with this drug are: memantine, methenamine.Check the labels on all your medicines because they may contain aspirin or aspirin-like drugs (salicylates), which can cause serious side effects if taken in large doses with this medication. However, if your doctor has directed you to take low-dose aspirin for heart attack or stroke prevention (usually 81-162 milligrams a day), you should continue taking it unless your doctor instructs you otherwise. Ask your doctor or pharmacist for more details.This medication may interfere with certain lab tests, possibly causing false test results. Make sure lab personnel and all your doctors know you use this drug.

                OVERDOSE: If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

                NOTES: Do not share this medication with others.Lab and/or medical tests (such as potassium level, complete blood count, liver function tests) should be done while you are taking this medication. Keep all medical and lab appointments. Consult your doctor for more details.

                MISSED DOSE: If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

                STORAGE: Store at room temperature away from light and moisture. Do not store in the bathroom. Keep all medications away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.

                Information last revised August 2021. Copyright(c) 2021 First Databank, Inc.

                IMPORTANT: HOW TO USE THIS INFORMATION: This is a summary and does NOT have all possible information about this product. This information does not assure that this product is safe, effective, or appropriate for you. This information is not individual medical advice and does not substitute for the advice of your health care professional. Always ask your health care professional for complete information about this product and your specific health needs.

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                Formulary

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                The above information is provided for general informational and educational purposes only. Individual plans may vary and formulary information changes. Contact the applicable plan provider for the most current information.

                Tier Description
                1 This drug is available at the lowest co-pay. Most commonly, these are generic drugs.
                2 This drug is available at a middle level co-pay. Most commonly, these are "preferred" (on formulary) brand drugs.
                3 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs.
                4 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
                5 This drug is available at a higher level co-pay. Most commonly, these are "non-preferred" brand drugs or specialty prescription products.
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                NC NOT COVERED – Drugs that are not covered by the plan.
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                Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.