Ethoxzolamide is a sulfonamide and carbonic anhydrase (CA) inhibitor with diuretic and anti-glaucoma activity. In the eye, ethoxzolamide inhibits CA, thereby decreasing the secretion of aqueous humor. This may relieve intraocular pressure. Also, this agent prevents reabsorption of bicarbonate and sodium in the proximal convoluted tubule thereby producing a mild diuresis.
Ethoxzolamide is a sulfonamide that is 1,3-benzothiazole-2-sulfonamide which is substituted by an ethoxy group at position 6. A carbonic anhydrase inhibitor, it has been used in the treatment of glaucoma, and as a diuretic. It has a role as an EC 4.2.1.1 (carbonic anhydrase) inhibitor, a diuretic, and an antiglaucoma drug. It is a member of benzothiazoles and a sulfonamide.
Ethoxzolamide is a sulfonamide used as a diuretic and in glaucoma. It inhibits carbonic anhydrase activity in proximal renal tubules to decrease the reabsorption of water, sodium, potassium, bicarbonate. Its pharmacological activity thus confers the risk for hypokalemia.
Mechanism of Action
Ethoxzolamide binds to and inhibits carbonic anhydrase I, which plays an essential role in facilitating the transport of CO2 and H+ in the intracellular space, across biological membranes, and in the layers of the extracellular space. Through inhibition of the enzyme, the balance of applicable membrane equilibrium systems are affected.
Ethoxzolamide is an inhibitor of the carbonic anhydrase enzyme in proximal renal tubules that works by decreasing the reabsorption of water, sodium, potassium, bicarbonate. It also decreases the activity of carbonic anhydrase expressed in the CNS, which leads to an increased seizure threshold. Inhibition of carbonic anhydrase in the eye contributes to its effect of reducing intraocular pressure and decreasing aqueous humor.
Indications of Ethoxzolamide
- For use in the treatment of duodenal ulcers, as a diuretic, and in the treatment of glaucoma, and may also be useful in the treatment of seizures associated with epilepsy.
- Carbonic Anhydrase Inhibitors; Diuretics
- For use in the treatment of duodenal ulcers, as a diuretic, and in the treatment of glaucoma, and may also be useful in the treatment of seizures associated with epilepsy.
- Carbonic anhydrase inhibitors enhance sodium excretion by reducing sodium bicarbonate reabsorption in the early proximal convoluted tubule. Passive sodium chloride reabsorption in the late proximal convoluted tubule is consequently decreased, potassium excretion is increased during initial therapy. Clinically significant hypokalemia is seldom a problem because excess hydrogen ions in the extracellular fluid tend to diffuse into the cells and displace potassium ions. After several days of continuous administration, a mild hyperchloremic acidosis develops, which decreases the diuretic effect.
Contraindications of Ethoxzolamide
- Information not available
Dosage
- Information not available
Side Effects of Ethoxzolamide
The most Common
- paresthesias, “tingling” feeling in the extremities,
- some loss of appetite,
- polyuria,
- occasional drowsiness,
- confusion and photosensitivity
- papular or erythematous skin eruptions,
- nausea,
- acidosis and blood dyscrasias.
- myopia, malaise syndrome,
- fatigue,
- anorexia,
- loss of weight,
- depression and loss of libido;
- gastrointestinal distress,
- elevated blood urate,
- acute gouty arthritis skin rashes and hair loss or excess growth of hair.
Common
- Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
- Signs of too much acid in the blood (acidosis) like confusion; fast breathing; fast heartbeat; a heartbeat that does not feel normal; very bad stomach pain, upset stomach, or throwing up; feeling very sleepy; shortness of breath; or feeling very tired or weak.
- Signs of electrolyte problems like mood changes, confusion, muscle pain or weakness, a heartbeat that does not feel normal, seizures, not hungry, or very bad upset stomach or throwing up.
- Change in eyesight.
- Change in hearing.
- Ringing in ears.
Rare
- Paresthesias, hearing dysfunction or tinnitus, anorexia, altered taste, nausea, vomiting, diarrhea, polyuria, drowsiness, confusion.
- A burning, numbness, or tingling feeling that is not normal.
- Pain when passing urine or blood in the urine.
- Not able to pass urine or change in how much urine is passed.
- Muscle weakness.
- Change in balance.
- Trouble moving around.
- Upset stomach or throwing up.
- Change in taste.
- Diarrhea.
- Not hungry.
- Blurred eyesight.
- Feeling dizzy, sleepy, tired, or weak.
- Headache.
- Flushing.
- Feeling nervous and excitable.
Drug Interactions of Ethoxzolamide
View interaction reports for ethoxzolamide and the medicines listed below.
- diphenhydramine
- CoQ10 ubiquinone
- duloxetine
- Fish Oil (omega-3 polyunsaturated fatty acids)
- furosemide
- pregabalin
- esomeprazole
- acetaminophen / hydrocodone
- acetaminophen
- albuterol
- magnesium salicylate
- metformin
- methazolamide
- dichlorphenamide
- dofetilide
- dronedarone
- droperidol
- citalopram
- clobazam
- clonazepam
- clorazepate
- clozapine
- corticorelin
- corticotropin
- cortisone
- montelukast
- levothyroxine
- topiramate
- acetaminophen
- Vitamin B12 (cyanocobalamin)
- Vitamin C (ascorbic acid)
- Vitamin D2 (ergocalciferol)
- Vitamin D3 (cholecalciferol)
- ondansetron
- cetirizine
Pregnancy Category
Pregnancy
Ethoxzolamide is pregnancy category B3 in Australia, which means that studies in rats, mice, and rabbits in which ethoxzolamide was given intravenously or orally caused an increased risk of fetal malformations, including defects of the limbs.[rx] Despite this, there is insufficient evidence from studies in humans to either support or discount this evidence.[rx]
Lactation
Limited data are available on the effects of nursing mothers taking ethoxzolamide. Therapeutic doses create low levels of breast milk and are not expected to cause problems in infants.[rx]
Before taking acetazolamide,
- tell your doctor and pharmacist if you are allergic toethoxzolamide sulfa drugs, diuretics (‘water pills’), or any other drugs.
- tell your doctor and pharmacist what prescription and nonprescription medications you are taking, especially amphetamines, aspirin, cyclosporine (Neoral, Sandimmune), medications for depression or irregular heartbeat, diflunisal (Dolobid), digoxin (Lanoxin), diuretics (‘water pills’), lithium (Eskalith, Lithobid), phenobarbital, primidone (Mysoline), and vitamins.
- tell your doctor if you have or have ever had heart, liver, or kidney disease; or diabetes.
- tell your doctor if you are pregnant, plan to become pregnant, or are breastfeeding. If you become pregnant while taking ethoxzolamide, call your doctor immediately.
- if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking ethoxzolamide.
- you should know that this drug may make you drowsy. Do not drive a car or operate machinery until you know how this drug affects you.
- remember that alcohol can add to the drowsiness caused by this drug.
- plan to avoid unnecessary or prolonged exposure to sunlight and to wear protective clothing, sunglasses, and sunscreen. Ethoxzolamide may make your skin sensitive to sunlight.
References