Furosemide
A loop diuretic given by mouth or injection for edema from heart failure, cirrhosis or kidney disease, acute pulmonary edema and hypertension.
Also called frusemide (older name).
Drug card
- Class
- Loop diuretic
- How it works
- Blocking NKCC2 in the loop of Henle, so much more salt and water is lost
- Used for
- Edema in heart failure
- Edema from cirrhosis or kidney disease
- Acute pulmonary edema
- High blood pressure
- Known for
- Low potassium
- Hearing loss and tinnitus, mainly with fast injection
- Its name
- -semide means a loop diuretic (furosemide type)
Study it as a flashcard, and it comes back before you forget it.
Mechanism of action
How does furosemide work?
A sulfonamide derived from anthranilic acid that blocks the Na-K-2Cl cotransporter in the thick ascending limb, so a brisk diuresis starts within minutes of an intravenous dose. It is highly bound to albumin and leaves mostly unchanged in urine, so a low albumin level weakens its effect and adds to its ototoxicity.
Like other loop diuretics: They block the Na-K-2Cl cotransporter (NKCC2) in the thick ascending limb of Henle's loop, reaching it from inside the tubule. Sodium, chloride and water are lost in large amounts, along with potassium, magnesium and calcium. The diuresis is strong and quick, and it still works when kidney function is poor.
Uses
What is furosemide used for?
- Edema in heart failure
- Edema from cirrhosis or kidney disease
- Acute pulmonary edema
- High blood pressure
Side effects
Side effects of furosemide
- Low potassiumKnown forSerious
- Hearing loss and tinnitus, mainly with fast injectionKnown forSerious
- Dehydration and dizziness on standing
- Low sodium
- Raised uric acid and gout
- Raised blood sugar
- Raised cholesterol and triglycerides
- PancreatitisSerious
- Sensitivity to sunlight and rash
- Stevens-Johnson syndrome and other severe skin reactionsSerious
- Low blood counts, including agranulocytosisSerious
- Interstitial nephritis or worsening kidney functionSerious
Known for marks what an exam expects you to know it for.
Watch for
Cautions and what sets it apart
- Contraindicated in anuria.
- Aminoglycosides, cisplatin and other ototoxic drugs raise the risk of hearing loss, as does rapid injection.
- Cirrhosis with ascites: sudden fluid and electrolyte shifts can precipitate hepatic encephalopathy and coma.
- Enlarged prostate or other bladder outflow problems: the extra urine can cause acute retention.
Good to know: Short acting: an intravenous dose works within 5 minutes and its diuresis lasts about 2 hours.
Remember it
A way to remember it
OH DANG
- O
- Ototoxicity
- H
- Hypokalemia
- D
- Dehydration
- A
- Allergy to sulfonamides
- N
- Nephritis (interstitial)
- G
- Gout
A mnemonic widely used in teaching
Its name
-semide means loop diuretic (furosemide type)
Furosemide and torasemide (US name torsemide) share it. Bumetanide, another loop diuretic, carries the stem -etanide instead.
- Every drug name stem
Its class
Loop diuretics
Other loop diuretics with a card:
Easily mixed up with thiazide and thiazide-like diuretics and mineralocorticoid receptor antagonists.
Sources
Checked against
Written for biofideX in plain words, after checking these references:
- Furosemide tablets: label (DailyMed)
- Furosemide injection: label (DailyMed)
- Furosemide (NHS)
- Furosemide (NCI Thesaurus)
For learning pharmacology, not for treatment decisions: no doses are given, and a prescriber, pharmacist or the product's own label is the word on any one patient. Spotted a mistake? Tell us and we'll correct it.
Heart failure, rhythm and angina
Furosemide is one of 10 drugs practiced together here: their classes, how they work, what they treat and what they're known for.
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