Lasix (furosemide) vs. hydrochlorothiazide: What's the difference?

What are Lasix and hydrochlorothiazide?

Lasix is a diuretic (water pill) used to eliminate water and salt from the body. In the kidneys, sodium and chloride (salt), water, and other small molecules are filtered out of the blood and into the tubules of the kidney, and ultimately become urine. Most of the salt and water filtered out of the blood is reabsorbed into the blood before the filtered fluid becomes urine and is eliminated from the body. Lasix blocks the absorption of sodium, chloride, and water from the filtered fluid in the kidney tubules, causing a profound increase in the output of urine (diuresis).

Hydrochlorothiazide is a diuretic prescribed to treat high blood pressure, edema caused by heart failure, cirrhosis, chronic kidney failure, nephrotic syndrome, and corticosteroid medications. Hydrochlorothiazide can be used to treat calcium-containing kidney stones because it decreases the amount of calcium excreted by the kidneys in the urine and thus decreases the amount of calcium in urine to form stones. It works by blocking salt and fluid reabsorption from the urine in the kidneys, causing increased urine output (diuresis).

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What are the side effects of Lasix and hydrochlorothiazide?

Lasix

Common side effects of furosemide are:

Other important side effects include:

Increased blood sugar and uric acid levels also may occur.

Hydrochlorothiazide

Side effects of hydrochlorothiazide include:

More serious side effects include:

Patients allergic to sulfa may also be allergic to hydrochlorothiazide because of the similarity in the chemical structure of the medications.

Hydrochlorothiazide can aggravate kidney dysfunction and is used with caution in patients with kidney disease. Hydrochlorothiazide can lower blood potassium, sodium, and magnesium levels. Low potassium and magnesium levels can lead to abnormalities in heart rhythm, especially in patients already taking digoxin (Lanoxin). During hydrochlorothiazide treatment, supplementation with potassium is common to prevent low potassium levels.

Blood uric acid levels can increase during hydrochlorothiazide treatment, and this elevation may cause an episode of acute gout in some individuals. Thiazide diuretics may increase blood sugar (glucose) levels and precipitate diabetes.

What is the dosage of Lasix vs. hydrochlorothiazide?

Lasix

  • The usual starting oral dose for treatment of edema in adults is 20 to 80 mg as a single dose. The same dose or an increased dose may be administered 6 to 8 hours later. Doses may be increased by 20 to 40 mg every 6 to 8 hours until the desired effect occurs. The effective dose may be administered once or twice daily. Some patients may require 600 mg daily.
  • The starting oral dose for children is 2 mg/kg. The starting dose may be increased by 1 to 2 mg/kg every 6 hours until the desired effect is achieved. Doses greater than 6 mg/kg are not recommended.
  • The recommended dose for treating hypertension is 40 mg twice daily. The dose of other blood pressure medications should be reduced by half when Lasix is added.

Hydrochlorothiazide

  • Hydrochlorothiazide may be taken with or without food.
  • The usual adult dose for hypertension is 12.5 to 50 mg once daily.
  • The usual adult dose for treating edema is 25 to 100 mg once daily or in divided doses.

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What drugs interact with Lasix and hydrochlorothiazide?

Lasix

  • Administration of Lasix with aminoglycoside antibiotics (for example, gentamicin) or ethacrynic acid (Edecrin, another diuretic) may cause hearing damage.
  • Lasix competes with aspirin for elimination in the urine by the kidneys. Concomitant use of Lasix and aspirin may, therefore, lead to high blood levels of aspirin and aspirin toxicity.
  • Lasix also may reduce excretion of lithium (Eskalith, Lithobid) by the kidneys, causing increased blood levels of lithium and possible side effects from lithium.
  • Sucralfate (Carafate) reduces the action of Lasix by binding Lasix in the intestine and preventing its absorption into the body. Ingestion of Lasix and sucralfate should be separated by two hours.
  • When combined with other antihypertensive drugs, there is an increased risk of low blood pressure or reduced kidney function.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) -- for example, ibuprofen, indomethacin (Indocin, Indocin-SR) -- may interfere with the blood pressure-reducing effect of Lasix.

Hydrochlorothiazide

  • Hydrochlorothiazide reduces the elimination of lithium (Lithobid, Eskalith) by the kidneys and can lead to lithium toxicity.
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) -- for example, ibuprofen (Motrin) -- may reduce the blood pressure lowering effects of hydrochlorothiazide.
  • Blood sugar levels can be elevated by hydrochlorothiazide, necessitating adjustment in the doses of medications that are used for treating diabetes.
  • Combining hydrochlorothiazide with corticosteroids may increase the risk for low levels of blood potassium and other electrolytes. Low blood potassium (hypokalemia) can increase the toxicity of digoxin (Lanoxin).
  • Cholestyramine (Questran, Questran Light) and colestipol (Colestid) bind to hydrochlorothiazide and reduce its absorption from the gastrointestinal tract by 43% to 85%.

Are Lasix and hydrochlorothiazide safe to use while pregnant or breastfeeding?

Lasix

Hydrochlorothiazide

  • There are no adequate studies of hydrochlorothiazide in pregnant women. Thiazides may increase the risk of fetal or neonatal jaundice, low platelet levels, and possibly other adverse reactions that have occurred in adults.
  • Hydrochlorothiazide is excreted in breast milk. Intense diuresis using hydrochlorothiazide may reduce the production of breast milk. Otherwise hydrochlorothiazide is considered safe to use during nursing if required by the mother.

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Summary

Lasix (furosemide) and hydrochlorothiazide are diuretics (water pills) used treat excess accumulation of fluid or swelling of the body (edema) caused by heart failure, kidney disease, chronic kidney failure, or liver disease. Lasix and hydrochlorothiazide are also used to treat high blood pressure (hypertension). Hydrochlorothiazide is also used to treat edema due to use of corticosteroid medications, and to treat calcium-containing kidney stones.

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Medically Reviewed on 6/7/2019
References
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