This page shows what was measured, who it was measured in, and what that does not settle.
What Furosemide does in the body
Furosemide blocks that transporter from the urine side, so that quarter stays in the urine and drags a large volume of water with it.
A quarter of the salt your kidneys filter is pulled back in one short stretch of tubing, by a single transporter. That is why the effect is so much larger than a thiazide, why it works within an hour, and why it also stops the kidney being able to concentrate urine at all.
Why people take it. Used to remove excess fluid caused by heart, liver or kidney disease.
What happened in people
Different furosemide dosing strategies relieved fluid overload without a clear winner.
✓ Reviewed first-read answer
Where this came from
A person wrote this and a reviewer approved it against this exact record. It carries no effect size.
A reviewer approved this against this record. The reviewed-claim record carrying the exact population and effect size does not exist yet.
No source is stored against this line.
The limit that matters most
Evidence that it reduces deaths compared with no water-removing medicine comes from only 202 people.
Where it acts
Luminal membrane of the thick ascending limb of the loop of Henle
Kind of result
The kind of result is not recorded
Supervision
RNAWiki has not recorded a supervision or regulatory status for this substance.
What the registries record it as
The substance registry classes this as chemical.
FDA substance registry · 7LXU5N7ZO5 · read 2026-08-29
Where each sentence above came from
A person wrote this explanation into the record, with the studies named in the path below.
A reviewer approved this sentence against this exact record and its sources.
The limit a reviewer approved as the one that matters most here.
The four opening statements run to 100 words.
Words this page uses
Four words worth knowing first
Chosen from what this page shows, with each one explained before the word it depends on.
Comparator
A comparator is whatever the treatment was measured against.
A picture of it, and where the picture fails
It is like the other runner in a race.
Where that stops being true. A race has one winner. A study can show both arms improved.
What people get wrong. Results are read without asking what the other group got. Beating nothing is not beating a treatment.
The control condition against which the experimental intervention is assessed.
Randomisation
Randomisation means chance decides who gets which treatment.
A picture of it, and where the picture fails
It is like a coin toss deciding the groups.
Where that stops being true. A coin toss is fair once. Fairness here comes from doing it for everyone.
What people get wrong. It is thought to make groups identical. It makes them similar on average, including on things nobody measured.
Allocation of participants to arms by a chance process, so that unmeasured factors are balanced in expectation.
Absolute difference
An absolute difference is how many more people in a hundred were affected.
A picture of it, and where the picture fails
It is like counting heads in two rooms of a hundred.
Where that stops being true. Heads are easy to count. Study results carry a margin of error too.
What people get wrong. It is confused with a percentage change, which can look far larger.
The arithmetic difference in event rates between arms.
Confidence interval
A confidence interval is the range the true answer is likely to sit in.
A picture of it, and where the picture fails
It is like a weather forecast giving a range rather than one number.
Where that stops being true. A forecast range covers tomorrow. This one covers what the study could resolve.
What people get wrong. The middle number is read as the answer. A range crossing zero means no change is still possible.
An interval estimate that would contain the true parameter in a stated proportion of repeated studies.
What happened in people◇Read from sources, not yet reviewed
What happened in people
Each card is one study: the exact question it asked, who was in it, and whether it showed what it set out to show.
Co-primary: patient global assessment of symptoms as area under the curve over 72 hours, and change in serum creatinine at 72 hours
Bolus versus infusion P = 0.47 and P = 0.45; high versus low dose P = 0.06 and P = 0.21
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. The high-dose strategy produced greater diuresis and more favourable results on some secondary measures alongside transient worsening of renal function.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet and oral solution, and an intravenous or intramuscular injection
Interval reported. Not recorded in this summary
Written into the record, not signed off as a reviewed claim.
Drugs@FDA: LASIX (furosemide), NDA 016273, original approval 1 July 1966 (https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&Ap… · a recorded source, not a stored snapshot
All-cause mortality, torsemide versus furosemide after heart failure hospitalisation
✗ The study did not show it
Who was studied
TRANSFORM-HF (NCT03296813)
How many people
2859
Study design
Pragmatic randomised open-label trial, median 17.4 months
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
What was found
26.1% against 26.2%; HR 1.02 (95% CI 0.89-1.18), against a prespecified hypothesis of a 20% reduction
Repeated elsewhere
Unreplicated
What this does not prove. A study that did not show an effect does not show that no effect exists anywhere.
The limits of this study, and where it came from
Main limit. The authors state interpretation is limited by loss to follow-up, crossover and non-adherence; 113 participants withdrew consent before completion.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet and oral solution, and an intravenous or intramuscular injection
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Drugs@FDA: LASIX (furosemide), NDA 016273, original approval 1 July 1966 (https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&Ap… · a recorded source, not a stored snapshot
Mortality and worsening heart failure, diuretics versus placebo or active control
✓ The study showed what it set out to show
Who was studied
Cochrane review: diuretics for heart failure
How many people
525
Study design
Systematic review and meta-analysis of 14 randomised trials
Compared against
Not recorded for this study
Kind of result
Living longer, or avoiding a major event
What was found
Odds ratio for death 0.24 (95% CI 0.07-0.83), P = 0.02 — from 3 placebo-controlled trials with 202 participants
Repeated elsewhere
Unreplicated
What this does not prove. Meeting one endpoint in one population does not carry to other goals or other people.
The limits of this study, and where it came from
Main limit. Only 202 of the 525 participants contributed mortality data. The 2012 update identified no new studies, so the evidence base has not grown.
How far it carries. This study is recorded from the curated record, not from the registry match.
Form and route. Oral tablet and oral solution, and an intravenous or intramuscular injection
Interval reported. 95% CI 0
Written into the record, not signed off as a reviewed claim.
Drugs@FDA: LASIX (furosemide), NDA 016273, original approval 1 July 1966 (https://www.accessdata.fda.gov/scripts/cder/daf/index.cfm?event=overview.process&Ap… · a recorded source, not a stored snapshot
What we know
RNAWiki holds 3 written-up human studies for this substance, each with the question it asked.
How we know it
Each card names the study, the number of people and what the study set out to measure.
What this does not prove
These summaries were written by a person and have not been signed off as reviewed claims.
Why it matters
A study that failed is as informative as one that worked, and both are here.
What we still do not know
No reviewed claim exists, so no exact population, effect size or interval is published yet.
What it changes in the body◇Read from sources, not yet reviewed
The path through the body
From what a person takes to what changes. A solid line is a step measured in people. A dashed line is a step nobody has measured that way.
Where a source records it acting
Kidneys: Inhibits primarily the absorption of sodium and chloride in the proximal and distal tubules and in the loop of Henle, as recorded
US prescribing information · 01a5f094-b473-4e46-9e61-69d5ec6dd766 · read 2026-08-27
Start
Furosemide
What a person takes: Oral tablet and oral solution, and an intravenous or intramuscular injection.
The measurement behind this step
Given once or twice daily by mouth, or intravenously in acute decompensation where gut wall oedema makes oral absorption unreliable. Duration is short, 6 to 8 hours, so a single daily dose leaves most of the day for compensatory sodium retention — the reason twice-daily dosing or a longer-acting agent is often preferred.
Getting in
Absorbed erratically by mouth, reliably by vein
How much of a tablet gets absorbed varies enormously between people and from day to day, especially when the gut wall is swollen with fluid. Intravenous dosing removes that uncertainty.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Oral bioavailability averages roughly 50% and ranges from about 10% to 100% between individuals, and falls further with gut wall oedema in decompensated heart failure. Onset is within 30 to 60 minutes orally and about 5 minutes intravenously, with a short duration of 6 to 8 hours. This variability is the practical reason torsemide, with more reliable absorption, was expected to be better — an expectation TRANSFORM-HF did not confirm.
It is secreted into the tubule because it cannot be filtered
The drug travels stuck to blood protein, so it is too large to be filtered into the urine. The kidney has to actively pump it across, and anything competing for that pump reduces the effect.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
More than 90% is albumin-bound, so glomerular filtration delivers almost none. Proximal tubular secretion by OAT1 and OAT3 is the route to the lumen. Hypoalbuminaemia, competing organic anions and reduced renal perfusion all cut luminal drug concentration, which is the commonest mechanism of apparent diuretic resistance.
It blocks the chloride site of the loop transporter
One transporter in the loop of Henle moves sodium, potassium and two chlorides at once and reclaims a quarter of all filtered salt. The drug occupies one of the chloride positions and shuts it down.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Furosemide binds the chloride-binding site of NKCC2, encoded by SLC12A1, on the luminal membrane of the thick ascending limb, which normally reabsorbs 20 to 25% of filtered sodium. Loss-of-function mutations in the same gene cause Bartter syndrome type 1, whose salt wasting, hypokalaemic alkalosis and hypercalciuria are a phenocopy of chronic loop diuretic use.
The kidney loses both its salt reclamation and its concentrating gradient
The same transporter that reclaims salt is what builds the salty gradient in the kidney that lets it make concentrated urine. Blocking it means large volumes of dilute urine, plus loss of potassium, magnesium and calcium.
╌╌Described, with no measurement named. No measurement is named for this step, so it is drawn as an unconfirmed link.
The measurement behind this step
Inhibiting NKCC2 abolishes the medullary countercurrent gradient, so the kidney can neither concentrate nor maximally dilute urine. Loss of the transepithelial potential normally generated by potassium recycling through ROMK removes the driving force for paracellular calcium and magnesium reabsorption, producing hypercalciuria and hypomagnesaemia. Increased distal sodium delivery drives potassium secretion and metabolic alkalosis. Furosemide also acutely increases venous capacitance through a prostaglandin-mediated effect, which is why breathlessness eases before diuresis begins.
Congestion clears within hours; survival has never been measured properly
Breathlessness improves within an hour and fluid comes off within a day. Whether the drug changes how long people live is a question no adequate trial has answered.
──Measured in people. Written by a person from the study named beside the step. Not signed off as a reviewed claim.
The measurement behind this step
Fractional sodium excretion rises to 20 to 25%, producing a diuresis far beyond what any thiazide achieves. Against that, DOSE separated on neither of its co-primary endpoints across four strategies in 308 patients, TRANSFORM-HF found all-cause death at 26.1% against 26.2% for torsemide versus furosemide in 2,859 patients, and the pooled placebo-controlled mortality evidence comprises 202 participants.
No suggested links are held for this record, so nothing is hidden from this path.
What we know
The record describes 5 steps from taking it to an effect in a person.
How we know it
Each step names the study behind it in the technical detail beside it.
What this does not prove
A change inside the body is a reason to look. It is not a result in a person.
Why it matters
A reader can see exactly where the chain stops being measured in people.
What we still do not know
No reviewed claim binds any of these steps to a named population.
What is missing or unclear◇Read from sources, not yet reviewed
Were people like you studied?
RNAWiki cannot tell whether a study fits you. It can show who was in it, and where the result stops carrying.
Who was studied
People similar to this profile were included.
Almost universal in acute decompensated heart failure, in chronic heart failure with congestion, in cirrhotic ascites and in nephrotic oedema. On the WHO Model List of Essential Medicines.
Who is missing from the studies
Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What the label states about particular groups
On pediatric, the label states: “Published reports indicate that premature infants with post conceptual age (gestational plus postnatal) less than 31 weeks receiving doses exceeding 1 mg/kg/24 hours may develop plasma levels which could be associated with potential toxic effects including ototoxicity [see Warnings and Precautions (5.3) ] .”
US prescribing information · 8e0bac29-5a8b-4d4e-93b3-2e21eb3b0650 · read 2026-08-30
On older people, the label states: “Controlled clinical studies of furosemide did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.”
US prescribing information · 8e0bac29-5a8b-4d4e-93b3-2e21eb3b0650 · read 2026-08-30
On people who are pregnant, the label states: “Data Animal Data The effects of furosemide on embryonic and fetal development and on pregnant dams were studied in mice, rats and rabbits.”
US prescribing information · 8e0bac29-5a8b-4d4e-93b3-2e21eb3b0650 · read 2026-08-30
On people who are breastfeeding, the label states: “Risk Summary The presence of furosemide has been reported in human milk.”
US prescribing information · 8e0bac29-5a8b-4d4e-93b3-2e21eb3b0650 · read 2026-08-30
Where the result stopped carrying
DOSE separated on neither co-primary endpoint across four furosemide strategies
TRANSFORM-HF was designed to detect a 20% mortality reduction from torsemide and found a hazard ratio of 1.02
The Cochrane 2012 update identified no new randomised trials to add to a base of 525 participants
This is a scope explorer, not a diagnosis engine.
It shows who was studied so you can see whether people similar to you were included.
RNAWiki cannot tell whether a study fits you. It can show who was in it.
What it would be like to take◇Read from sources, not yet reviewed
Why it might seem to do nothing
A real effect and a noticed effect are different things. These are the recorded reasons the two come apart.
It was studied in different people
The people in the studies were not much like the reader.
On this record: Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
The evidence may simply be wrong
Small early studies often do not hold up.
On this record: RNAWiki has not yet published a reviewed conclusion for this use.
Other reasons RNAWiki checked and found nothing for (11)
It was studied for a different goal
The studies measured something else entirely. Nothing in this record points to this reason.
A different form was studied
The studied form is not the form on the shelf. Nothing in this record points to this reason.
There was nothing to correct
Where a level is already normal, topping it up may change nothing. Nothing in this record points to this reason.
Something else had to happen too
In the studies it was paired with training, a diet or another treatment. Nothing in this record points to this reason.
The change is too small to feel
A real change can still sit below what a person notices. Nothing in this record points to this reason.
Day-to-day swing hides it
Sleep, food, stress and time of day move most numbers more than this would. Nothing in this record points to this reason.
Not enough time yet
The studies ran longer than the person has waited. Nothing in this record points to this reason.
It was not taken as studied
Missed days change the result, and studies count them. Nothing in this record points to this reason.
Something else changed at the same time
Two changes at once cannot be told apart afterwards. Nothing in this record points to this reason.
The product may not be what it says
Contents of a sold product are not always what the label states. Nothing in this record points to this reason.
No recorded reason
RNAWiki has nothing stored that would explain it. Nothing in this record points to this reason.
None of these is a reason to take more. Taking more is not a step this page ever suggests.
What it would be like to take◇Read from sources, not yet reviewed
What taking it involves
The recorded facts about getting hold of it and using it. Nothing here is a suggestion about what you should do.
How it is supplied
Given by a clinician
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
Read from the recorded approval status.
No source is stored against this line.
Form and route
Oral tablet and oral solution, and an intravenous or intramuscular injection
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form and route recorded on this substance.
No source is stored against this line.
Who oversees it
RNAWiki has not recorded a supervision or regulatory status for this substance.
❝ Quoted from a source
Where this came from
Copied from a source RNAWiki stored, with the source named.
No register row and no identity class settled the question.
No source is stored against this line.
What is in the pack
Given once or twice daily by mouth, or intravenously in acute decompensation where gut wall oedema makes oral absorption unreliable.
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
Recorded notes on how this is sold. The rest of the recorded wording: Duration is short, 6 to 8 hours, so a single daily dose leaves most of the day for compensatory sodium retention — the reason twice-daily dosing or a longer-acting agent is often preferred.
No source is stored against this line.
Where it is registered
Regulatory records are listed in the technical disclosure at the foot of this page.
# Counted from records
Where this came from
A count of rows RNAWiki holds. It describes our records, not your body.
Register entries are stored per jurisdiction and shown with their dates.
No source is stored against this line.
Why people stop
Not recorded.
∅ Nothing recorded
Where this came from
RNAWiki holds nothing here and says so rather than guessing.
No record of why people stopped taking it is stored for this substance.
No source is stored against this line.
What it would be like to take◇Read from sources, not yet reviewed
What can go wrong
Sorted by where each line came from. A regulator's label and a report somebody sent in are not the same kind of fact.
·Worth asking a clinician aboutWritten into the record from the studies named on this page
The US label carries a warning that furosemide is a potent diuretic which, if given in excessive amounts, can lead to profound diuresis with water and electrolyte depletion. Hypokalaemia, hyponatraemia, hypomagnesaemia, hypocalcaemia and metabolic alkalosis all follow directly from the mechanism. Ototoxicity, usually reversible, relates to peak concentration and is more likely with rapid high-dose intravenous administration, renal impairment and concurrent aminoglycosides. It is a sulfonamide derivative. Non-steroidal anti-inflammatories blunt the effect by competing for tubular secretion.
Nobody counted how many people took this and were fine, so this cannot be turned into a rate.
Over a long time. No completed tested study window is recorded, so long-term effects are not established by the registry record.
Groups the studies covered thinly. Which groups were under-represented in the studies has not been recorded for this substance. Pregnancy, breastfeeding, children, older adults, and people with liver or kidney conditions are commonly excluded from trials; nothing here says whether they were.
What is missing or unclear◇Read from sources, not yet reviewed
Does the exact form matter?
Evidence belongs to the exact thing that was tested. A different salt, a different mixture or a different preparation is a different question.
The form that was studied
Oral tablet and oral solution, and an intravenous or intramuscular injection
✎ Source-linked record
Where this came from
A person wrote this into the record with the study named beside it. No reviewer has signed it off.
The form used in the studies cited on this page.
No source is stored against this line.
What is sold
A recorded note compares this form with the others that are sold. It is kept below, word for word.
§ A fixed RNAWiki sentence
Where this came from
Wording RNAWiki always uses, not a finding about this substance.
The recorded note, unchanged: Duration is short, 6 to 8 hours, so a single daily dose leaves most of the day for compensatory sodium retention — the reason twice-daily dosing or a longer-acting agent is often preferred.
No source is stored against this line.
What is recorded as being sold
244 products list this as an active ingredient in the United States drug directory. 244 of them contain it and nothing else.
FDA National Drug Code directory · 0409-6102 · read 2026-08-29
They are sold as injection, injection, solution, powder, solution and tablet, taken intramuscular, intravenous, oral and subcutaneous.
FDA National Drug Code directory · 0409-6102 · read 2026-08-29
The regulator's established pharmacologic class for it is increased diuresis at loop of henle [pe] and loop diuretic [epc].
FDA National Drug Code directory · 0409-6102 · read 2026-08-29
152 published labels name it as an active ingredient. 152 of them describe this substance alone, which is where its own label text on this page comes from.
US prescribing information · 4b3e2e13-a657-4da5-b536-8ae0a26812e0 · read 2026-08-29
Those labels are classed as human prescription drug.
US prescribing information · 4b3e2e13-a657-4da5-b536-8ae0a26812e0 · read 2026-08-29
3 marketed supplement labels list this ingredient, classed as other combinations and vitamin.
Those labels carry all other, nutrient and structure/function claims. A claim of that kind is written by the manufacturer and is not assessed by any regulator, so its presence says nothing about whether it is true.
Furosemide is tablets at 80 mg, recorded as prescription product; fda label in effect 2023-03-01 in the United States.
US prescribing information · 01a5f094-b473-4e46-9e61-69d5ec6dd766 · read 2026-08-27
Recorded price in US: 0.02676–0.05075 USD per one unit as the pricing file counts it — a tablet, capsule, patch or single item, across 43 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Recorded price in US: 0.09092–0.46162 USD per one millilitre, across 38 priced products whose strengths and pack forms differ, as of 2026-08-26, paid by retail pharmacies buying the product, as surveyed by the Centers for Medicare & Medicaid Services. It is not a list price, an insurance price, or what anyone pays at a counter..
Recorded source · 2026-08-26 · read 2026-08-28
Evidence carries across two names for one substance. It does not carry across a salt, a mirror form or a mixture.
What it would be like to take◇Read from sources, not yet reviewed
What you could measure
This one is decided with a clinician, so this section holds questions to ask rather than a plan to run.
RNAWiki could not confidently classify this substance, so no self-experiment plan is offered.
Questions worth asking
Which of the trials of Furosemide studied people like me?
What was measured, and for how long?
Was the result a laboratory value or a health outcome?
What would we watch for, and when would we stop?
Tracking can show whether something changed for you. It cannot show what caused it.
RNAWiki records evidence. It does not say whether this substance is right for you.
What is missing or unclear◇Read from sources, not yet reviewed
Claims that go past the evidence
Things said about this substance that sound reasonable, and the exact step that is missing between the evidence and the claim.
✗Goes past the evidence
That the immediate relief of congestion implies a survival benefit — the placebo-controlled mortality evidence is 202 participants and no large trial exists
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That better oral bioavailability makes a loop diuretic better — TRANSFORM-HF tested that with torsemide and found 26.1% against 26.2%
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That observational associations between higher loop diuretic doses and worse survival indicate harm — that is far more likely to be confounding by severity, and no randomised data resolve it
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
✗Goes past the evidence
That failing to respond means the dose is too low — it more often means insufficient drug is reaching the transporter
Why it sounds right. It follows from something real on this page: a body step, an animal result or a related finding.
The missing step. Nobody measured this in people for this use, or the study that did measure it did not show it.
What would change this
A study in people, for this exact use, measuring this exact thing, that a reviewer signs off.
RNAWiki has not yet published a reviewed conclusion for this use.
What is missing or unclear◇Read from sources, not yet reviewed
What nobody knows yet
Open questions, each with why it is open and what would close it.
Missing populations
Which groups were under-represented in the studies has not been recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing long-term data
No completed tested study window is recorded.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
No reviewed conclusion
RNAWiki has not yet published a reviewed conclusion for this use.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Missing interaction studies
No interaction was found in the registers checked. Not finding one is not the same as showing there is none.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Formulation uncertainty
Several salts, forms or products of Furosemide are recorded. Results from one form may not transfer to another.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
Mechanism not reviewed
No reviewed mechanism story exists for this substance.
Why it matters. Recorded by the evidence model as a gap on this record.
What would answer it
A study that measures it, and a reviewer to sign it off.
Last checked 2026-09-04. Searched: The sources listed in the receipts at the foot of this page.
What happened in people◇Read from sources, not yet reviewed
Check any of this yourself
Every line above traced back to the study it came from. This is the technical layer, and the vocabulary changes here.
Every line above can be traced to the study named beside it. Follow the link and read it.
The placebo-controlled mortality evidence is 202 participants across three trials
In plain words
Furosemide is given to almost every patient admitted with heart failure. The pooled randomised evidence that a diuretic reduces death compared with no diuretic comes from three small trials with 202 people between them.
What was measured
Pooled odds ratio for death from diuretics versus placebo in chronic heart failure, across 3 trials and 202 participants
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The Cochrane review of diuretics for heart failure includes 14 trials with 525 participants in total, of which 7 were placebo-controlled and 7 compared diuretics with other agents such as ACE inhibitors or digoxin. Mortality data were available in only 3 of the placebo-controlled trials, comprising 202 participants: the odds ratio for death was 0.24 (95% CI 0.07 to 0.83), p=0.02. Admission for worsening heart failure was reduced in 2 trials with 169 participants, odds ratio 0.07 (0.01 to 0.52), p=0.01. Four trials comparing diuretics with active control in 91 participants found improved exercise capacity, weighted mean difference 0.72 (0.40 to 1.04), p<0.0001. The 2012 update identified no new studies for inclusion. An odds ratio of 0.24 on 202 participants with an interval running to 0.83 is a real signal on a very small base, and no large trial has ever been run because withholding a loop diuretic from a congested patient is not something investigators will randomise.
Written into the record, not signed off as a reviewed claim
DOSE: neither co-primary endpoint separated between four strategies
In plain words
Three hundred patients hospitalised with heart failure were randomised to furosemide given by injection or infusion, and at a low or high dose. Neither comparison changed symptoms or kidney function significantly.
What was measured
Global symptom assessment area under the curve over 72 hours and change in serum creatinine
Effect estimate
No reviewed effect estimate exists for this record.
Limits
This entry records a failure.
From the source
The DOSE trial randomised 308 patients with acute decompensated heart failure in a 2-by-2 design to intravenous furosemide by bolus every 12 hours or by continuous infusion, and at a low dose equal to the previous oral dose or a high dose 2.5 times it, with protocol-permitted adjustment after 48 hours. The co-primary endpoints were the patient global symptom assessment as area under a visual analogue scale curve over 72 hours, and change in serum creatinine at 72 hours. Bolus against continuous infusion: symptom area under the curve 4,236 against 4,373, p=0.47; creatinine change 0.05 against 0.07 mg/dL, p=0.45. High against low dose: symptom area under the curve 4,430 against 4,171, p=0.06 — a non-significant trend; creatinine change 0.08 against 0.04 mg/dL, p=0.21. The high-dose strategy produced greater diuresis and more favourable results on some secondary measures alongside transient worsening of renal function.
Written into the record, not signed off as a reviewed claim
TRANSFORM-HF: torsemide was expected to beat furosemide and did not
In plain words
Torsemide is better absorbed and lasts longer, and the trial was designed on the expectation that it would cut deaths by a fifth. Deaths were 26.1% against 26.2%.
What was measured
All-cause mortality over a median 17.4 months, torsemide versus furosemide
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
TRANSFORM-HF randomised 2,859 participants discharged after hospitalisation for heart failure, median age 65, 36.9% women and 33.9% Black, to a loop diuretic strategy of torsemide (n=1,431) or furosemide (n=1,428) at investigator-selected dose, with follow-up to 30 months for death and 12 months for hospitalisations. The prespecified primary hypothesis was that torsemide would reduce all-cause mortality by 20%. Over a median 17.4 months, death occurred in 373 of 1,431 (26.1%) on torsemide and 374 of 1,428 (26.2%) on furosemide: hazard ratio 1.02 (95% CI 0.89 to 1.18). Over 12 months, all-cause mortality or all-cause hospitalisation occurred in 47.3% against 49.3% (hazard ratio 0.92, 0.83 to 1.02), and total hospitalisations were 940 in 536 participants against 987 in 577 (rate ratio 0.94, 0.84 to 1.07). Results were similar across ejection fraction strata. The authors state that interpretation is limited by loss to follow-up, crossover and non-adherence; 113 patients withdrew consent before completion.
Written into the record, not signed off as a reviewed claim
Symptom relief within hours is not evidence about outcomes over years
In plain words
Nobody doubts that furosemide relieves breathlessness, and that certainty is often carried across into claims about survival and hospitalisation that the trials do not support.
What was measured
That the visible acute benefit of furosemide implies a survival benefit — no adequately sized randomised trial has tested it and none is likely to be run
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The acute effect is unambiguous, mechanistically direct and visible within an hour, which makes it one of the most convincing bedside demonstrations in medicine. What follows from it about long-term outcome does not follow at all. DOSE, the largest randomised trial of furosemide strategy in acute heart failure, used a symptom score and a creatinine change as its co-primary endpoints and separated on neither. TRANSFORM-HF compared two loop diuretics for death and found 26.1% against 26.2%. The Cochrane placebo-controlled mortality evidence is 202 participants. Meanwhile observational analyses consistently associate higher loop diuretic doses with worse survival, which is almost certainly confounding by severity and is also not a finding anyone can dismiss on the available randomised data. The accurate summary is that furosemide is indispensable for congestion and that its effect on survival has never been properly measured.
Written into the record, not signed off as a reviewed claim
Diuretic resistance is a delivery problem more often than a dose problem
In plain words
When furosemide stops working, the usual reason is not that the transporter has become insensitive but that not enough drug is reaching it.
What was measured
Diuresis, symptom score and creatinine change with a high-dose versus low-dose furosemide strategy
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
Furosemide is more than 90% bound to plasma albumin, so it is barely filtered at the glomerulus and reaches its luminal target almost entirely by OAT-mediated secretion in the proximal tubule. Three things reduce that delivery: hypoalbuminaemia, which is common in the nephrotic syndrome and cirrhosis; competing organic anions, including uraemic retention solutes and non-steroidal anti-inflammatories; and reduced renal blood flow. A fourth mechanism operates downstream — chronic loop diuretic exposure causes compensatory hypertrophy and increased sodium reabsorption in the distal convoluted tubule, the braking phenomenon, which is why adding a thiazide to a loop diuretic restores diuresis when raising the loop dose does not. DOSE tested the dose lever specifically: the high-dose strategy produced greater diuresis and more favourable secondary measures with transient worsening of renal function, and did not reach significance on either co-primary endpoint.
Written into the record, not signed off as a reviewed claim
Ototoxicity comes from the same transporter family in the inner ear
In plain words
High doses given quickly into a vein can cause temporary hearing loss and ringing, because the ear uses a close relative of the transporter the drug blocks.
What was measured
Peak-concentration-dependent inhibition of the cochlear NKCC1 transporter, as reflected in labelled ototoxicity warnings
Effect estimate
No reviewed effect estimate exists for this record.
Limits
See the technical detail.
From the source
The stria vascularis of the cochlea maintains the potassium-rich endolymph on which hearing depends, using NKCC1, a close relative of the NKCC2 target in the kidney. At high plasma concentrations furosemide inhibits it, reducing the endocochlear potential and producing tinnitus and reversible hearing loss. The effect is peak-concentration dependent rather than dose-cumulative, which is why rapid intravenous administration of a large dose carries more risk than the same dose given as an infusion, and why risk rises in renal impairment where clearance is reduced. Concurrent aminoglycoside antibiotics compound it through a separate and typically permanent mechanism. The kidney-versus-ear selectivity of the drug is therefore a matter of concentration rather than of molecular discrimination.
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Felt, measured, or meaningful — found nothing in the sources checked.
How long anything takes — found nothing in the sources checked.
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The older medicine-wide conclusion held in this record
Written for a clinical reader, and about the medicine as a whole rather than about one indication, population and set of trials. RNAWiki does not treat it as a programme conclusion and no reviewer has signed it off in that form. It is here word for word because it is what the record holds.
The most powerful diuretic in routine use and one of the least tested against placebo: the DOSE trial randomised 308 patients between four furosemide strategies and found no significant difference on either co-primary endpoint, TRANSFORM-HF found torsemide and furosemide identical for death in 2,859 patients, and the Cochrane placebo-controlled mortality evidence rests on 202 participants.
Recorded evidence blocks (9)
Q1
On the Furosemide label: indicated for what?
"FUROSEMIDE INJECTION is a loop diuretic indicated for: The treatment of edema associated with heart failure, cirrhosis of the liver, and renal disease ( 1.1 ) Acute pulmonary edema as adjunctive therapy ( 1.2 ) 1.1 Edema Furosemide Injection is indicated in adults and pediatric patients for the treatment of edema…": indications and usage on Furosemide's label. DailyMed label · 58cc1e38-6000-1489-e063-6394a90a5978 · 2026-08-11
Q2
199 registered trials of Furosemide — at which phases?
Registered studies posting no result
144 of 199
199 registered studies of Furosemide: 45 na, 43 phase1, 43 phase4, 36 phase3, 34 phase2, 8 early phase1, 5 na or unstated. CLINICALTRIALS_SNAPSHOT · 2026-09-01
1274 with a PubMed record
Show the evidence
na
45
phase1
43
phase4
43
phase3
36
phase2
34
early phase1
8
9 more recorded rows
na or unstated
5
completed
109
unknown
23
terminated
19
recruiting
17
withdrawn
16
not yet recruiting
7
active not recruiting
5
enrolling by invitation
3
recorded 2026-09-01 · last checked 2026-09-04
Q3
32 of Furosemide's trials stopped: safety, futility/efficacy, accrual/recruitment, funding/business, other?
safety (1), futility/efficacy (1), accrual/recruitment (14), funding/business (3) and other (13): Furosemide's stop wording, clustered. CLINICALTRIALS_SNAPSHOT · 2026-09-01
"The study has ceased recruiting as Ethics approval has lapsed and the investigator availability reduced."; 32 of 199 registered studies
Show the evidence
Trial
NCT00246675
withdrawn; "The study has ceased recruiting as Ethics approval has lapsed and the investigator availability reduced."
NCT00298454
terminated; "Number included has been reached"
NCT00372762
withdrawn; "Due to changes within the research program this study is not feasible at this time"
NCT00904488
terminated; "Difficult recruitment"
NCT00936923
withdrawn; "The study was withdrawn prior to enrollment of first participant."
NCT00962286
terminated; "The blood pressure did not decrease following furosemide administration"
14 further recorded trials
NCT00978354
terminated; "Feasibility of target enrollment within the context of available funding resources."
NCT01054404
terminated; "Concern for volume depletion and electrolyte abnormalities in furosemide arm."
NCT01073189
withdrawn; "withdrew due to funding"
NCT01156220
withdrawn; "Study was never implemented."
NCT01210365
terminated; "EF decided suspended the study because the investigational product was changed."
NCT01474200
terminated; "Closed due to patient recruitment challenges. No interim analyses were completed; study closure was not related to any concerns about safety or futility."
NCT01558674
terminated; "Lack of efficacy"
NCT01705470
withdrawn; "PI left the medical center, no replacement assigned"
NCT02047422
withdrawn; "One of the diuretic which is planned to be used in the study is no longer available."
NCT02312115
withdrawn; "Lack of funding"
NCT02458157
terminated; "Very low recruitment rates"
NCT02649998
withdrawn; "Lack of funding"
NCT02767024
withdrawn; "No patients enrolled"
NCT02800135
terminated; "departure of the coordinating investigator from another institution"
recorded 2026-09-01 · last checked 2026-09-04
Q4
Human studies of Furosemide used furosemide 80 mg tablets — over how long?
Human studies of Furosemide used "furosemide 80 mg tablets". ClinicalTrials.gov · 2026-09-01
18 recorded entries; human; injection, subcutaneous, infusion; also "Furosemide 60 mg", "Product name: Lasix 40 mg Injektionslösung", "Frusemide 20mg"
Show the evidence
human
NCT00778180
furosemide 80 mg tablets
NCT01125514
Furosemide 60 mg
NCT01156220
Product name: Lasix 40 mg Injektionslösung
NCT01852669
Frusemide 20mg
NCT02028689
Furosemide 40 mg
NCT02350725
injection; Furosemide injection solution for subcutaneous administration (80 mg)
12 more recorded rows
humanNCT02350725
Oral Furosemide tablets (80 mg)
humanNCT02832973
Furosemide 20-40 mg
humanNCT03093090
Furosemide 20 MG
humanNCT03509545
CHF Patients: Furosemide 40 mg
humanNCT04161482
Furosemide 80 mg (8 mg/mL)
humanNCT04384653
subcutaneous; Furosemide Injection Solution for subcutaneous administration (80 mg)
humanNCT04919564
Furosemide in 0.9 % NaCl 100 Mg/100 mL (1 mg/mL)
humanNCT04982874
Lasix® 40 mg Tablet
humanNCT05652322
Furosemide Pill 150% equivalent iv dose
humanNCT05652322
Furosemide Pill 200% equivalent iv dose
humanNCT06203236
Lasix 20 MG
humanNCT07269496
infusion; Sanofi Aventis 20mg/2mL Lasix infusion
recorded 2026-09-01 · last checked 2026-09-04
Q5
Furosemide's half-life is 2 hours — which schedules were studied?
2 hours; Elimination The terminal half-life of furosemide is approximately 2 hours.
bioavailabilitypharmacokinetics
79 %; Bioavailability of enteral dose compared to IV dose was estimated to be around 79%.
metabolismpharmacokinetics
Metabolism Recent evidence suggests that furosemide glucuronide is the only or at least the major biotransformation product of furosemide in man.
recorded 2026-08-11 · last checked 2026-09-04
Q6
Which 57 trials of Furosemide posted no result?
Posted no result
57 of 57 completed trials
Registrations
NCT00306696, NCT00151827, NCT00778180, NCT00115726, NCT00671424 and NCT00478543, and 51 more
Completion dates
oldest 2004-01; newest 2024-08-27
Show the evidence
Trial
NCT00306696
2004-01
NCT00151827
2005-07
NCT00778180
2005-11
NCT00115726
2007-04
NCT00671424
2008-05
NCT00478543
2008-07
14 further recorded trials
NCT00909519
2009-04
NCT00409942
2009-06
NCT00531908
2009-12
NCT00355667
2010-08
NCT01419132
2011-09
NCT01611415
2011-10
NCT01028170
2012-01
NCT01724788
2013-01
NCT01628731
2013-11
NCT02028689
2014-01
NCT02231931
2015-01-01
NCT02350725
2015-06
NCT02372292
2015-06
NCT01407848
2015-07
Q7
At the median, Furosemide's trials enrolled 50 people — anything larger?
Median enrolment
50
Largest enrolment
22213
Registered trials counted
197
Q8
What do 17357 spontaneous reports say about Furosemide — and not say?
These are reports people sent to a regulator. They do not show the medicine caused the reaction. Nobody counted how many people took the medicine and reported nothing. The same event can be reported more than once, and many reports are incomplete. News coverage, lawsuits and new warnings change how often people report. A count is not a rate and not a risk.
Furosemide appears in spontaneous reports to regulators. Across the 10 most-reported reaction terms, 17357 reaction mentions were counted: acute kidney injury 3595; hypotension 2393; hyponatraemia 1793; fall 1689. FAERS via Open Targets · CHEMBL35 · 2026-06-24
Show the evidence
acute kidney injury
3595
hypotension
2393
hyponatraemia
1793
fall
1689
hypokalaemia
1595
dehydration
1592
4 more recorded rows
hyperkalaemia
1253
renal failure acute
1171
drug interaction
1152
syncope
1124
recorded 2026-06-24 · last checked 2026-09-04
Q9
Which 10 reactions does Furosemide's label not list?
ChEMBL 37 — CC BY-SA 3.0 Unported · ChEMBL ATC CC BY-SA · ClinicalTrials.gov — US Government work · Open Targets 26.06 — CC0 · mixed register set; per-register licences in docs/specs/corpus-20k-sources.md · openFDA / DailyMed — US Government work
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✓ public claims reviewed: 0 reviewed claim(s); drafts are never rendered
✓ source coverage passed: 6 source rows
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