Methazolamide

Methazolamide is an antihypertensive agent belonging to Carbonic Anhydrase Inhibitor.

Methazolamide is a carbonic anhydrase inhibitor used to treat open-angle glaucoma and acute angle closure glaucoma.

Methazolamide is well absorbed from the gastrointestinal tract. Time to peak plasma concentration and Peak plasma concentration of Methazolamide were found to be approximately 6-8 hours and 2.5 -10.7 mcg/mL, respectively. Methazolamide is distributed throughout the body including the plasma, cerebrospinal fluid, aqueous humor of the eye, red blood cells, bile, and extra-cellular fluid. The mean apparent volume of distribution ranges from 17 L to 23 L. Approximately 55% is bound to plasma proteins. The elimination half-life for Methazolamide is approximately 14 hr. 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 drugs.

Methazolamide shows common side effects like Nausea, loss of appetite, change in taste, vomiting, diarrhea, frequent urination, dizziness, drowsiness, tiredness, etc.

Methazolamide is available in the form of Oral Tablets.

Methazolamide is available in India, the US, the UK, Canada, Africa, China, Hong Kong, Japan, and Australia.

Methazolamide belonging to the Carbonic Anhydrase Inhibitor acts as an antihypertensive agent.

Methazolamide is a noncompetitive inhibitor of the enzyme carbonic anhydrase; thought that carbonic anhydrase is located at the luminal border of cells of the proximal tubule. When the enzyme is inhibited, there is an increase in the urine volume and a change to an alkaline pH with a subsequent decrease in the excretion of titratable acid and ammonia.

The onset of action of Methazolamide occurs within 2-4 hours.

The Duration of Action for Methazolamide in the body is approximately 10-14 hours.

The Tmax was found within 6-8 hours, and the Peak plasma concentration of Methazolamide was found to be approximately 6-8 hours and 2.5 -10.7 mcg/mL

Methazolamide is available in the form of Oral Tablets.

Methazolamide Tablets are taken orally, and it is usually taken two or three times a day.

Methazolamide is a carbonic anhydrase inhibitor used to treat open-angle glaucoma and acute angle closure glaucoma. This medication treats 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.

Methazolamide is an antihypertensive agent belonging to Carbonic Anhydrase Inhibitor.

Methazolamide's inhibitory action on carbonic anhydrase reduces the secretion of aqueous humor and results in a reduction in intraocular pressure. Methazolamide is a carbonic anhydrase inhibitor used to treat open-angle glaucoma and acute angle closure glaucoma.

Methazolamide is approved for use in the following clinical indications

• Glaucoma

Methazolamide tablets are indicated in the treatment of ocular conditions where lowering intraocular pressure is likely to be of therapeutic benefits, such as chronic open-angle glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where lowering the intraocular pressure is desired before surgery.

• Glaucoma

50 to 100 mg orally 2 or 3 times a day. May be used concomitantly with miotic and osmotic agents.

Use: Treatment of ocular conditions where lowering intraocular pressure is likely to be of therapeutic benefits, such as chronic open-angle glaucoma, secondary glaucoma, and preoperatively acute angle-closure glaucoma.

Methazolamide is available in various strengths as 25mg and 50mg.

Methazolamide is available in the form of Oral Tablets.

• Methazolamide therapy is contraindicated in situations in which sodium and/or potassium serum levels are depressed, in cases like;

It should not be marked as kidney or liver disease or dysfunction,

In adrenal gland failure,

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.

• Hypersensitivity reaction

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.

• Concomitant Therapy

Caution is advised for patients receiving concomitant high-dose aspirin and Methazolamide, as anorexia, tachypnea, lethargy, coma, and death have been reported.

• In Patients with pulmonary obstruction or emphysema

In patients with pulmonary obstruction or emphysema, where alveolar ventilation may be impaired, Methazolamide should be used with caution because it may precipitate or aggravate acidosis.

• In patients with hepatic impairment

Potassium excretion is increased initially upon administration of Methazolamide and in patients with cirrhosis or hepatic insufficiency could precipitate a hepatic coma.

Consumption of alcohol is not recommended as drowsiness and dehydration are caused by Methazolamide.

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Methazolamide, 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.

Animal studies have revealed evidence of teratogenicity. There are no controlled data on human pregnancy.

Pregnancy category C: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant the use of the drug in pregnant women despite potential risks. This drug should be used during pregnancy only if the benefit outweighs the risk to the fetus.

No information is available.

• Common Adverse effects

Weakness, Malaise, loss of appetite, Metallic taste, anorexia, polyuria, mental disturbance, drowsiness, dizziness, and confusion.

• Rare Adverse effects

Fever, headache, seizures, fatigue, rash, Stevens-Johnson syndrome, hyperchloremic metabolic acidosis, hypokalemia, hyperglycemia, GI irritation, constipation, xerostomia, black tarry stools, bone marrow suppression, dysuria, melaena, crystalluria, paresthesia, myopia, tinnitus, loss of smell and hypersensitivity.

• Steroid therapy

Methazolamide should be used with caution in patients on steroid therapy because of the potential for developing hypokalemia.

• Aspirin

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

• Lithium

Methazolamide increases lithium excretion, and the lithium level may be decreased.

• Digoxin

Metabolic effects of hypokalemia may be increased with concomitant digitalis therapy.

The common side effect of Methazolamide include the following

• Common
  

Nausea, loss of appetite, change in taste, vomiting, diarrhea, frequent urination, dizziness, drowsiness, or tiredness.

• Rare

Painful urination, fever, chills, bloody urine, sore throat that doesn't go away, fever, numbness or tingling of hands and feet, ringing in the ears.

• Pregnancy

Pregnancy category C: 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 on pregnant women. Methazolamide should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.

• Nursing Mothers

It is not known whether this drug is excreted in human milk. Because many drugs are excreted in human milk and because of the potential for serious adverse reactions in nursing infants from Methazolamide, 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 Use

The safety and effectiveness of Methazolamide in children have not been established.

• Geriatric Use

No information is available.

• 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.

Pharmacodynamic

Methazolamide is a carbonic anhydrase inhibitor. Methazolamide is indicated for the reduction of elevated intraocular pressure in patients with open-angle glaucoma or ocular hypertension who are insufficiently responsive to beta-blockers. 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.

Pharmacokinetics

• Absorption

Methazolamide is well absorbed from the gastrointestinal tract. Time to peak plasma concentration and Peak plasma concentration of Methazolamide were found to be approximately 6-8 hours and 2.5 -10.7 mcg/mL respectively.

• Distribution

Methazolamide is distributed throughout the body including the plasma, cerebrospinal fluid, aqueous humor of the eye, red blood cells, bile, and extra-cellular fluid. The mean apparent volume of distribution ranges from 17 L to 23 L. Approximately 55% is bound to plasma proteins.

• Metabolism and Excretion

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 drugs.

• https://www.drugs.com/pro/methazolamide.html#s-34067-9
• https://reference.medscape.com/drug/methazolamide-342826
• https://go.drugbank.com/drugs/DB00703
• https://www.syrianclinic.com/med/en/ProfDrugs/Methazolamidepd.html#dosage
• https://www.uptodate.com/contents/methazolamide-drug-information