Furosemide: uses, dosing, side effects & brands
Furosemide is a loop diuretic sold in the U.S. under 4 brand and generic names, for ascites, edema and heart failure. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.
Key facts
- Drug class
- Loop Diuretic
- Treats (across its forms)
- Ascites, Edema and Heart Failure
- Available as
- Tablet · Injectable
- Sold as
- 4 products — Lasix, Furoscix and Furosemide, and others
- Prescription?
- Prescription only
- Generic available?
- Yes
- Half-life
- about 2 hours (terminal elimination half-life in adults with normal kidney function)
- What the pharmacy pays
- about $0.05 per ml — not your price
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How Lasix is dosed
From the FDA label for Lasix (application NDA016273). Other furosemide products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.
Edema Therapy should be individualized according to patient response to gain maximal therapeutic response and to determine the minimal dose needed to maintain that response. Adults -- The usual initial dose of LASIX is 20 mg to 80mg given as a single dose. Ordinarily a prompt diuresis ensues. If needed, the same dose can be administered 6 to 8 hours later or the dose may be increased. The dose may be raised by 20 mg or 40mg and given not sooner than 6 to 8 hours after the previous dose until the desired diuretic effect has been obtained. The individually determined single dose should then be given once or twice daily (e.g., at 8 am and 2 pm). The dose of LASIX may be carefully titrated up to 600 mg/day in patients with clinically severe edematous states. Edema may be most efficiently and safely mobilized by giving LASIX on 2 to 4 consecutive days each week. When doses exceeding 80 mg/day are given for prolonged periods, careful clinical observation and laboratory monitoring are particularly advisable ( s ee PRECAUTIONS: Laboratory Test ) . Geriatric patients -- In general, dose selection for the elderly patient should be cautious, usually starting at the low end of the dosing range ( see PRECAUTIONS: Geriatric Use ). Pediatric patients -- The usual initial dose of oral LASIX in pediatric patients is 2 mg/kg body weight, given as a single dose. If the diuretic response is not…
Everything below is the FDA label for Lasix (tablet). Furosemide is also sold as injectable, and those are different medicines to take — follow the label for the one you were prescribed.
Lasix side effects
Adverse reactions are categorized below by organ system and listed by decreasing severity. Gastrointestinal System Reactions 1. hepatic encephalopathy in patients with hepatocellular insufficiency 6. oral and gastric irritation 7. cramping 2. pancreatitis 8. diarrhea 3. jaundice (intrahepatic cholestatic jaundice) 9. constipation 4. increased liver enzymes 10. nausea 5. anorexia 11. vomiting Systemic Hypersensitivity Reactions 1. Severe anaphylactic or anaphylactoid reactions (e.g., with shock) 3. interstitial nephritis 4. necrotizing angiitis 2. systemic vasculitis Central Nervous System Reactions 1. tinnitus and hearing loss 5. headache 2. paresthesias 6. blurred vision 3. vertigo 7. xanthopsia 4. dizziness Hematologic Reactions 1. aplastic anemia 5. leukopenia 2. thrombocytopenia 6. anemia 3. agranulocytosis 7. eosinophilia 4. hemolytic anemia Dermatologic-Hypersensitivity Reactions 1. toxic epidermal necrolysis 7. bullous pemphigoid 2. Stevens-Johnson Syndrome 3. erythema multiforme 8. purpura 9. photosensitivity 4. drug rash with eosinophilia and systemic symptoms 10. rash 11. pruritis 5. acute generalized exanthematous pustulosis 6. exfoliative dermatitis 12. urticaria Cardiovascular Reaction 1. Orthostatic hypotension may occur and be aggravated by alcohol, barbiturates, or narcotics. 2. Increase in cholesterol and triglyceride serum levels Other Reactions 1.…
Who shouldn’t take Lasix
LASIX is contraindicated in patients with anuria and in patients with a history of hypersensitivity to furosemide.
Lasix drug interactions
LASIX may increase the ototoxic potential of aminoglycoside antibiotics, especially in the presence of impaired renal function. Except in life-threatening situations, avoid this combination. LASIX should not be used concomitantly with ethacrynic acid because of the possibility of ototoxicity. Patients receiving high doses of salicylates concomitantly with LASIX, as in rheumatic disease, may experience salicylate toxicity at lower doses because of competitive renal excretory sites. There is a risk of ototoxic effects if cisplatin and LASIX are given concomitantly. In addition, nephrotoxicity of nephrotoxic drugs such as cisplatin may be enhanced if LASIX is not given in lower doses and with positive fluid balance when used to achieve forced diuresis during cisplatin treatment. LASIX has a tendency to antagonize the skeletal muscle-relaxing effect of tubocurarine and may potentiate the action of succinylcholine. Lithium generally should not be given with diuretics because they reduce lithium’s renal clearance and add a high risk of lithium toxicity. LASIX combined with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers may lead to severe hypotension and deterioration in renal function, including renal failure. An interruption or reduction in the dosage of LASIX, angiotensin-converting enzyme inhibitors, or angiotensin receptor blockers may be necessary. Potentiation occurs with ganglionic or peripheral adrenergic blocking drugs. LASIX may decrease arterial responsiveness to norepinephrine. However, norepinephrine may still be used effectively. Simultaneous administration of sucralfate and LASIX tablets may reduce the natriuretic and antihypertensive effects of LASIX. Patients receiving both drugs should be observed closely to determine if the desired diuretic and/or antihypertensive effect of LASIX is achieved. The intake of LASIX and sucralfate should be separated by at least two hours. In isolated cases, intravenous administration of LASIX within 24 hours of taking chloral hydrate may lead to flushing, sweating attacks, restlessness, nausea, increase in blood pressure, and tachycardia. Use of LASIX concomitantly with chloral hydrate is therefore not recommended. Phenytoin interferes directly with renal action of LASIX. There is evidence that treatment with phenytoin leads to decreased intestinal absorption of LASIX, and consequently to lower peak serum furosemide concentrations. Methotrexate and other drugs that, like LASIX, undergo significant renal tubular secretion may reduce the effect of LASIX. Conversely, LASIX may decrease renal elimination of other drugs that undergo tubular secretion. High-dose treatment of both LASIX and these other drugs may result in elevated serum levels of these drugs and may potentiate their toxicity as well as the toxicity of LASIX. LASIX can increase the risk of cephalosporin-induced nephrotoxicity even in the setting of minor or transient renal impairment. Concomitant use of cyclosporine and LASIX is associated with increased risk of gouty arthritis secondary to LASIX-induced hyperurecemia and cyclosporine impairment of renal urate excretion. High doses (>80mg) of furosemide may inhibit the binding of thyroid hormones to carrier proteins and result in transient increase in free thyroid hormones, followed by an overall decrease in total thyroid hormone levels. One study in six subjects demonstrated that the combination of furosemide and acetylsalicylic acid temporarily reduced creatinine clearance in patients with chronic renal insufficiency. There are case reports of patients who developed increased BUN, serum creatinine and serum potassium levels, and weight gain when furosemide was used in conjunction with NSAIDs. Literature reports indicate that coadministration of indomethacin may reduce the natriuretic and antihypertensive effects of LASIX (furosemide) in some patients by inhibiting prostaglandin synthesis. Indomethacin may also affect plasma renin levels, aldosterone excretion, and renin profile evaluation. Patients receiving both indomethacin and LASIX should be observed closely to determine if the desired diuretic and/or antihypertensive effect of LASIX is achieved.
Every furosemide product we track (4)
Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.
| # | Drug | Rating | Type | Form | Generic? | Pharmacy pays | |
|---|---|---|---|---|---|---|---|
| 1 | 72/100 | Prescription | Tablet | Generic | $0 | View → | |
| 2 | Not yet rated | Prescription | Injectable | Generic | $0 | View → | |
| 3 | Not yet rated | Prescription | Injectable | Generic | $0 | View → | |
| 4 | Not yet rated | Prescription | Injectable | Generic | $0 | View → |
What furosemide pills look like
Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.
| Imprint | Strength | Colour | Shape | Maker |
|---|---|---|---|---|
| EP;116 | 20 mg | white | round | — |
| RE;22 | 20 mg | white | round | — |
| EP;116 | 20 mg | white | round | — |
| 3169;V | 20 mg | white | oval | — |
| 3170;V | 40 mg | white | round | — |
| 17;0 | 40 mg | white | round | — |
| EP;117;40 | 40 mg | white | round | — |
| G164 | 20 mg | white | round | — |
| G;165 | 40 mg | white | round | — |
| G;166 | 80 mg | white | round | — |
| EP;116 | 20 mg | white | round | — |
| 3169;V | 20 mg | white | oval | — |
Furosemide recalls
From the FDA Enforcement database. A recall covers specific lots — not the drug as a whole.
How long furosemide keeps
No furosemide label we read sets a separate limit for after opening, but they do specify how it must be stored — and the stability behind any date assumes those conditions.
Furosemide and breastfeeding
From LactMed, the US National Library of Medicine’s Drugs and Lactation Database — quoted, not rewritten.
Full LactMed record for furosemide: levels in milk, effects in breastfed infants, and the drugs it would consider insteadBecause little information is available on the use of furosemide during breastfeeding and because intense diuresis from high doses might decrease lactation, an alternate drug may be preferred, especially while nursing a newborn or preterm infant. Low doses of furosemide (20 mg daily) do not suppress lactation.
National Institute of Child Health and Human Development, record revised January 15, 2025. LactMed states its information is not a substitute for professional judgement.
What people report to the FDA about furosemide
The FDA Adverse Event Reporting System (FAERS) collects reports from patients and clinicians. It holds 274,019 reports naming furosemide, and the FDA flagged 83% of those reports as serious. The effects reported most often — leaving out reports about overdose, misuse or the condition being treated, which dominate the raw list for common medicines:
- dyspnoea18,964 reports
- acute kidney injury16,839 reports
- fatigue13,600 reports
- diarrhoea13,553 reports
- nausea11,882 reports
- fall11,392 reports
- hypotension10,590 reports
- pneumonia10,421 reports
Read these as a signal, not a rate. A report does not mean furosemide caused the effect — anyone can file one, and many describe people taking several medicines for several conditions. Crucially there is no denominator: FAERS does not record how many people took the drug, so these counts cannot be turned into “X% of patients” — a bigger number often just means a more widely used or more talked-about drug. Duplicates exist, and publicity drives reporting. For what is actually established, read the FDA label.
Source: openFDA drug/event (FAERS), retrieved September 25, 2026.
How long furosemide stays in your system
The elimination half-life of furosemide is about 2 hours (terminal elimination half-life in adults with normal kidney function). Linear kinetics — the label gives a single terminal half-life ("approximately 2 hours"). Furosemide is not a prodrug and has no clinically important active metabolite: its major biotransformation product, furosemide glucuronide, is not described as active. The half-life is prolonged when clearance falls — in reduced kidney function, in heart or liver failure, and especially in neonates — so the drug lingers longer in those groups. In a healthy adult, roughly 4–5 half-lives (about 8–10 hours) clears essentially all of a dose from the blood.
Furosemide Tablet — FDA label (DailyMed SPL), Clinical Pharmacology ↗Half-life is how long the body takes to clear half a dose. It is not the same as how long a drug test can detect it, and it varies with age, kidney and liver function.
Related calculators
Frequently asked questions
What is Lasix?
LASIX ® is a diuretic which is an anthranilic acid derivative.
What kind of drug is furosemide?
The FDA classifies furosemide as a loop diuretic. Loop diuretics such as furosemide block a salt-transport protein (the Na-K-2Cl cotransporter) in a part of the kidney called the loop of Henle. This stops sodium and chloride from being reabsorbed, so the body flushes out extra salt and water, relieving fluid buildup and swelling. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
How long does furosemide stay in your system?
The elimination half-life of furosemide is about 2 hours (terminal elimination half-life in adults with normal kidney function) — that is how long the body takes to clear half of a dose. Linear kinetics — the label gives a single terminal half-life ("approximately 2 hours"). Furosemide is not a prodrug and has no clinically important active metabolite: its major biotransformation product, furosemide glucuronide, is not described as active. The half-life is prolonged when clearance falls — in reduced kidney function, in heart or liver failure, and especially in neonates — so the drug lingers longer in those groups. In a healthy adult, roughly 4–5 half-lives (about 8–10 hours) clears essentially all of a dose from the blood. Half-life is not the same as how long a drug test can detect the drug, and it varies with age, kidney and liver function.
Can you take furosemide with other medicines?
It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run furosemide against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is furosemide sold under?
We track 4 furosemide-containing products in the U.S.: Lasix, Furoscix, Furosemide and Lasix Onyu. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does furosemide come in?
Across the brands we track, furosemide is currently marketed as tablet and injectable, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.
Is there a generic furosemide?
Yes. Our catalog lists 1 generic furosemide product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.
Has furosemide been recalled?
The FDA's Enforcement database lists 2 recall records whose product description mentions furosemide. The most recent: Furosemide Tablets (Mar 20, 2026). A recall applies to specific lots, not to the drug as a whole — check the record for the affected lot numbers.
What are the common side effects of furosemide, and do they go away?
The most common effect is simply urinating more often, which is the drug working; it is heaviest in the first few hours after a dose and eases as your body adjusts. Dizziness or lightheadedness when standing up is also common and usually fades over the first week or two as your dose settles. Other frequent effects include headache and muscle cramps. Take it early in the day so the increased urination does not disrupt sleep.
Which furosemide side effects are dangerous and mean I should call a doctor?
Furosemide's main risk is losing too much fluid and too many electrolytes. Call your doctor for muscle cramps, unusual weakness, an irregular or pounding heartbeat, or numbness and tingling, which can signal low potassium, sodium, or magnesium. Signs of dehydration such as very little urine, extreme thirst, dry mouth, confusion, or fainting also need prompt attention. Sudden ringing in the ears or hearing loss is a warning of ototoxicity and should be reported right away.
Can furosemide damage your hearing?
Yes, though it is uncommon with normal oral doses. Hearing loss or ringing in the ears (usually temporary) is linked mainly to high intravenous doses given too quickly, and to use in people with kidney problems or alongside other ear-toxic drugs like certain antibiotics. Any new ringing, muffled hearing, or hearing loss should be reported to your doctor promptly.
How do I tell normal furosemide effects from ones that mean stop and get help?
Urinating more, mild thirst, and passing lightheadedness when you stand are expected and manageable. What is not routine: fainting, a racing or irregular heartbeat, severe or persistent cramps and weakness, confusion, sudden hearing changes, or signs of a serious allergic reaction (rash, swelling of the face or throat, trouble breathing). Those mean stop and seek care. Because furosemide can strongly deplete fluid and electrolytes, your doctor will usually monitor blood tests periodically.
Cite this page
- APA
- pharmaranks. (2026, July 24). Furosemide: uses, dosing, side effects & brands. https://pharmaranks.com/drugs/furosemide
- MLA
- “Furosemide: uses, dosing, side effects & brands.” pharmaranks, 24 July 2026, https://pharmaranks.com/drugs/furosemide.
We summarise public FDA and NIH sources — for a clinical claim, cite the primary source we link to as well.
Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.
Read the full FDA label for furosemide on DailyMed (NIH) ↗.