Overview
DESCRIPTION Ethacrynic acid is an unsaturated ketone derivative of an aryloxyacetic acid. It is designated chemically as [2,3-dichloro-4-(2- methylene-1-oxobutyl)phenoxy] acetic acid, and has a molecular weight of 303.14. Ethacrynic acid is a white, or practically white, crystalline powder, very slightly soluble in water, but soluble in most organic solvents such as alcohols, chloroform, and...
Mechanism of Action
CLINICAL PHARMACOLOGY Pharmacokinetics and Metabolism Ethacrynate sodium acts on the ascending limb of the loop of Henle and on the proximal and distal tubules. Urinary output is usually dose dependent and related to the magnitude of fluid accumulation. Water and electrolyte excretion may be increased several times over that observed with thiazide diuretics, since ethacrynate sodium inhibits reabsorption of a much greater proportion of filtered sodium than most other diuretic agents. Therefore, ethacrynate sodium is effective in many patients who have significant degrees of renal insufficiency (see WARNINGS concerning deafness ).
Indications
- INDICATIONS AND USAGE Ethacrynate sodium is indicated for treatment of edema when an agent with greater diuretic potential than those commonly employed is required. 1. Treatment of the edema associated with congestive heart failure, cirrhosis of the liver, and renal disease, including the nephrotic syndrome. 2. Short-term management of ascites due to malignancy, idiopathic edema, and lymphedema. 3. Short-term management of hospitalized pediatric patients, other than infants, with congenital heart disease or the nephrotic syndrome. 4.
Common Doses
- 25 mg
- 100 mg
- 200 mg
- 50 mg
Dosage
DOSAGE AND ADMINISTRATION Dosage must be regulated carefully to prevent a more rapid or substantial loss of fluid or electrolyte than is indicated or necessary. The magnitude of diuresis and natriuresis is largely dependent on the degree of fluid accumulation present in the patient. Similarly, the extent of potassium excretion is determined in large measure by the presence and magnitude of aldosteronism. Oral Use Ethacrynic Acid Tablets USP are available as 25 mg tablets.
Contraindications
- CONTRAINDICATIONS All diuretics, including ethacrynic acid, are contraindicated in anuria. If increasing electrolyte imbalance, azotemia, and/or oliguria occur during treatment of severe, progressive renal disease, the diuretic should be discontinued. In a few patients this diuretic has produced severe, watery diarrhea. If this occurs, it should be discontinued and not used again. Until further experience in infants is accumulated, therapy with parenteral ethacrynate sodium is contraindicated. Hypersensitivity to any component of this product.
Side Effects
- ADVERSE REACTIONS Gastrointestinal Anorexia, malaise, abdominal discomfort or pain, dysphagia, nausea, vomiting, and diarrhea have occurred. These are more frequent with large doses or after one to three months of continuous therapy. A few patients have had sudden onset of profuse, watery diarrhea. Discontinue ethacrynate sodium if diarrhea is severe and do not give it again. Gastrointestinal bleeding has occurred in some patients. Rarely, acute pancreatitis has been reported. Metabolic Reversible hyperuricemia and acute gout have been reported.
Interactions
- Drug Interactions Lithium generally should not be given with diuretics because they reduce its renal clearance and add a high risk of lithium toxicity. Read circulars for lithium preparations before use of such concomitant therapy. Ethacrynate sodium may increase the ototoxic potential of other drugs such as aminoglycoside and some cephalosporin antibiotics. Their concurrent use should be avoided. A number of drugs, including ethacrynic acid, have been shown to displace warfarin from plasma protein; a reduction in the usual anticoagulant dosage may be required in patients receiving both drugs.