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Ethacrynic Acid

( Ethacrynate )

Pronunciation: eth-a-KRIN-ik AS-id
Class: Loop diuretic

Trade Names

- Tablets, oral 25 mg

Edecrin Sodium
- Injection, powder for solution 50 mg (as ethacrynate sodium)


Inhibits reabsorption of sodium and chloride in proximal and distal tubules and in loop of Henle.



Approximately 100% bioavailable.


Does not cross the blood-brain barrier.


The half-life is 60 to 90 min (oral).


Within 30 min (oral), 5 min (IV).


2 h (oral), 15 to 30 min (IV).


6 to 8 h (oral), 30 to 60 min (IV).

Indications and Usage

Treatment of edema associated with CHF, hepatic cirrhosis, or renal disease; short-term treatment of ascites caused by malignancy, idiopathic edema, and lymphedema; short-term management of hospitalized children (other than infants) with congenital heart disease or the nephrotic syndrome.

Parenteral product is indicated for use when oral intake is impractical or in urgent conditions, such as acute pulmonary edema.

Unlabeled Uses

Treatment of glaucoma; treatment of nephrogenic diabetes insipidus, hypercalcemia.


Anuria; infants; patients who have experienced severe, watery diarrhea with prior use; hypersensitivity to any component of the product.

Dosage and Administration

Adults PO

Start with 50 mg once daily after a meal on day 1, 50 mg twice daily after meals on day 2 if necessary, and 100 mg in the morning and 50 to 100 mg following the afternoon or evening meal on day 3. Usual dose is 50 to 200 mg every day; may be given on a continuous or intermittent dosage schedule. Make dosage adjustments in 25 to 50 mg increments.


50 mg (0.5 to 1 mg/kg); usually only 1 dose is necessary but a second dose may be given if required. Single doses not exceeding 100 mg have been used in critical situations.


PO 25 mg initially; careful stepwise increments in dosages of 25 mg should be made to achieve effective maintenance.

Concomitant therapy
Carbonic anhydrase inhibitors

When adding ethacrynic acid, the initial dose and changes of dose should be in 25 mg increments to avoid electrolyte depletion.

General Advice

  • PO
  • Administer after a meal.
  • IV
  • Administer IV only. Subcutaneous or IM injection causes local pain and irritation.
  • To prepare IV solution, add 50 mL of dextrose 5% injection or sodium chloride injection to the vial. If solution is hazy or opalescent, do not use.
  • For IV dose, administer drug slowly. Rotate injection sites to avoid thrombophlebitis.
  • Do not administer drug with other drugs or with blood products.


Store between 59° and 86°F. Discard reconstituted solution if not used within 24 h.

Drug Interactions

Aminoglycosides (eg, gentamicin), certain cephalosporins, cisplatin

May increase risk of auditory toxicity. Avoid coadministration.


Electrolyte disturbances may predispose to digoxin-induced atrial and ventricular arrhythmias. Closely monitor serum potassium (and possibly magnesium). Replace electrolytes as needed.


May increase plasma lithium levels and toxicity. Avoid coadministration.

NSAIDs (eg, ibuprofen)

May decrease effects of ethacrynic acid. When ethacrynic acid and NSAIDs are given concomitantly, closely monitor patients to determine if the desired diuretic effect is obtained.

Thiazide diuretics

Synergistic effects may result in profound diuresis and serious electrolyte abnormalities. Carefully titrate with small or intermittent doses. Monitor patients for dehydration and electrolyte abnormalities during combined therapy.


Warfarin may be displaced from plasma protein. Monitor coagulation parameters and adjust the warfarin dose as needed.

Adverse Reactions


Apprehension, confusion, fatigue, headache, malaise, vertigo with a sense of fullness in the ears.




Blurred vision, deafness, tinnitus.


Abdominal discomfort or pain; acute pancreatitis; anorexia; diarrhea; GI bleeding; nausea; sudden profuse, watery diarrhea; vomiting.




Agranulocytosis, Henoch-Schönlein purpura, severe neutropenia, thrombocytopenia.


Abnormal LFTs, jaundice.


Acute gout, acute symptomatic hypoglycemia with convulsions, hyperglycemia, hyperuricemia.


Chills, fever, local irritation and pain with parenteral administration.



Perform frequent serum electrolyte, CO 2 , and BUN determinations early in therapy and periodically thereafter during active diuresis. Correct any electrolyte abnormalities or withdraw the drug temporarily.


Category B .




Contraindicated in infants. Safety and effectiveness of IV use in children have not been established.


Take care in dose selection because elderly patients are more likely to have decreased renal function.

Renal Function

Contraindicated in anuria. If increasing electrolyte imbalance, azotemia, and/or oliguria occurs during treatment of severe, progressive renal disease, discontinue use.

Hepatic Function

Initiation of treatment in cirrhotic patients with ascites is best carried out in the hospital. Use with caution in patients with advanced cirrhosis of the liver, especially those with a history of previous episodes of electrolyte imbalance or hepatic encephalopathy.

Special Risk Patients

Possible drug-related deaths have occurred in critically ill patients and have generally occurred in patients with severe myocardial disease receiving digitalis who developed hypokalemia with fatal arrhythmia and patients with severely decompensated hepatic cirrhosis with ascites who were in electrolyte imbalance.


Excessive diuresis may cause dehydration and decreased blood volume with circulatory collapse and possible vascular thrombosis and embolism, especially in elderly patients.

Electrolyte imbalance

If given in excessive amounts, may lead to profound diuresis with water and electrolyte depletion. May be more likely in patients receiving large doses with restricted salt intake.

Gastric hemorrhage

May increase risk associated with corticosteroid treatment.

Glucose effects

Increases in blood glucose and alterations in glucose tolerance tests have been observed.

Hepatic cirrhosis and ascites

Sudden alterations of electrolyte balance may precipitate hepatic encephalopathy and coma.


An increase in urinary excretion of magnesium may lead to hypomagnesemia.

Orthostatic hypotension

May occur in patients receiving other antihypertensive agents.


Associated with rapid injection, very large doses, and concurrent use of other ototoxic drugs. Occurs more frequently in patients with severe renal impairment.

Renal effects

A transient increase in BUN may occur.



Dehydration, electrolyte depletion.

Patient Information

  • Instruct patient to take oral dose after a meal.
  • Advise patient to avoid exposure to sunlight or UV light and to use sunscreen or wear protective clothing to avoid photosensitivity reaction.
  • Caution patient to avoid sudden position changes to prevent orthostatic hypotension.
  • Instruct patient to report the following symptoms to health care provider: blood in urine or stool, confusion or mood changes, diarrhea, dizziness, increased thirst, irregular heartbeat, muscle weakness or cramps, sudden joint pain, any changes in hearing, weakness or increased tiredness.
  • Advise patients with diabetes mellitus to monitor blood glucose levels closely.

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