Comprehensive medication guide to Furosemide including estimated pricing, availability information, side effects, and how to find it in stock at your local pharmacy.
Estimated Insurance Pricing
$0–$10 copay for generic on most commercial plans; Tier 1 on virtually all formularies. Medicare Part D coverage is universal with very low copays. Medicaid covers furosemide in all states at $0–$3 copay.
Estimated Cash Pricing
$10–$25 retail for generic furosemide tablets; as low as $1.80–$2.80 with GoodRx or SingleCare coupons for a 30-day supply. Warehouse pharmacies like Costco and Walmart often stock it for under $10 without any coupon.
Medfinder Findability Score
90/100
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Furosemide is a loop diuretic—commonly called a "water pill"—used to treat fluid retention (edema) and high blood pressure. Sold under the brand name Lasix, it has been in clinical use since 1966 and is on the World Health Organization's List of Essential Medicines. In 2023, furosemide was the 29th most commonly prescribed medication in the United States with over 19 million prescriptions dispensed.
Furosemide is FDA-approved to treat edema caused by congestive heart failure, liver cirrhosis, and kidney disease (including nephrotic syndrome). It is also approved for hypertension, typically as a second-line agent or in patients who also have significant kidney or heart disease. Off-label uses include hypercalcemia, acute pulmonary edema, and ascites management.
Furosemide is available in oral tablets (20 mg, 40 mg, 80 mg), oral solution (10 mg/mL), intravenous/intramuscular injection (10 mg/mL), and a newer subcutaneous formulation called Furoscix (80 mg/10 mL), which allows at-home delivery via an on-body infusor for qualifying heart failure patients.
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Furosemide works by inhibiting the Na-K-2Cl cotransporter (NKCC2) in the thick ascending limb of the kidney's loop of Henle. This transporter normally reabsorbs sodium, potassium, and chloride from filtered urine back into the bloodstream. By blocking it, furosemide prevents this reabsorption—keeping sodium and water in the urine—resulting in dramatically increased urine output.
The loop of Henle is responsible for reabsorbing approximately 25% of filtered sodium—far more than any other diuretic target site. This is why loop diuretics like furosemide are the most potent class of diuretics available. The diuretic effect begins within 1 hour of an oral dose, peaks at 1–2 hours, and lasts 6–8 hours. Intravenous furosemide acts within minutes and also has a mild vasodilatory effect that provides rapid symptom relief in pulmonary edema.
A key side effect of this mechanism is potassium loss (hypokalemia), since potassium is co-transported with sodium and chloride in the same transporter. Regular potassium monitoring and supplementation are important components of long-term furosemide management.
20 mg — tablet
Starting dose for mild edema or hypertension in adults
40 mg — tablet
Most commonly prescribed oral dose; can be split for 20 mg dosing
80 mg — tablet
Used for moderate-to-severe edema; less commonly stocked
10 mg/mL — oral solution
Liquid form for patients who cannot swallow tablets
10 mg/mL — injectable solution (IV/IM)
Hospital use; twice as potent as oral; active shortage conditions in 2026
80 mg/10 mL — subcutaneous kit (Furoscix)
At-home on-body infusor; specialty pharmacy only
Oral furosemide tablets are generally widely available at most retail pharmacies in the United States and are not on the FDA's active shortage list in 2026. As one of the 30 most prescribed medications in the country, it is stocked in large quantities at chain pharmacies (CVS, Walgreens, Walmart) and warehouse clubs (Costco, Sam's Club). The 40 mg tablet is the most commonly stocked strength; 20 mg and 80 mg may require checking multiple locations.
Furosemide injection (IV/IM) has experienced periodic shortage conditions, most recently in late 2025 and early 2026, affecting hospital and clinical settings. The oral solution (10 mg/mL) is less commonly stocked and may require specialty pharmacy sourcing. Furoscix (subcutaneous) is available only through specialty pharmacies.
If you're having trouble filling your furosemide prescription, medfinder can call pharmacies near you to locate your specific strength in stock. Results are texted to you directly, saving you hours of calling around.
Furosemide is not a controlled substance, which means any licensed prescriber can write a prescription for it without special DEA authorization or prescriber registration. It is widely prescribed across many medical specialties.
Primary Care Physicians (family medicine, internal medicine)
Cardiologists and heart failure specialists
Nephrologists (kidney specialists)
Hepatologists and gastroenterologists (for liver cirrhosis)
Nurse practitioners (NPs) and physician assistants (PAs) in most states
Emergency medicine physicians (for acute care situations)
Furosemide can also be prescribed via telehealth in most states for appropriate indications, such as managing chronic hypertension or monitoring stable edema in established patients. However, new diagnoses of heart failure, significant kidney disease, or severe edema typically require in-person evaluation with physical examination and laboratory testing.
No. Furosemide is not a controlled substance and is not classified under any DEA schedule. It can be prescribed by any licensed healthcare provider—including primary care physicians, cardiologists, nephrologists, nurse practitioners, and physician assistants—without any special DEA registration or requirements.
Prescriptions for furosemide can be called in, faxed, or sent electronically. Refills are allowed as written by the prescriber, with no state-mandated limits beyond what the prescriber specifies. Furosemide can also be prescribed via telehealth in most states for appropriate indications such as chronic hypertension management or stable edema monitoring.
Increased urination (especially in the first 1–6 hours after a dose)
Dizziness and lightheadedness (especially when standing up)
Low potassium (hypokalemia) — muscle cramps, weakness, fatigue
Thirst and dry mouth
Nausea and stomach upset
Photosensitivity (skin sensitive to sunlight)
Hearing loss or ringing in the ears (ototoxicity) — especially at high doses or with aminoglycosides
Severe dehydration — decreased urination, extreme thirst, confusion
Severe hypotension (very low blood pressure) — fainting, severe dizziness
Worsening kidney function — reduced urine output, swelling, elevated creatinine
Gout attack — joint pain, redness, and swelling due to elevated uric acid
Severe skin reactions (Stevens-Johnson syndrome, TEN, DRESS) — seek emergency care immediately
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Torsemide
Loop diuretic with once-daily dosing and better oral bioavailability than furosemide; ~2:1 conversion ratio (furosemide 40 mg ≈ torsemide 20 mg). May reduce heart failure hospitalizations.
Bumetanide (Bumex)
Loop diuretic 40 times more potent than furosemide per mg. Faster onset; higher bioavailability. Requires very careful dose conversion (40 mg furosemide ≈ 1 mg bumetanide).
Ethacrynic Acid (Edecrin)
The only loop diuretic without a sulfonamide structure. Reserved for patients with confirmed sulfa allergy. Higher risk of ototoxicity than furosemide.
Hydrochlorothiazide (HCTZ)
Thiazide diuretic; much less potent than furosemide; suitable for mild hypertension or edema without significant heart/kidney disease.
Spironolactone (Aldactone)
Potassium-sparing diuretic often combined with furosemide to offset potassium losses. Good for heart failure and cirrhosis-related ascites.
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Aminoglycoside antibiotics (gentamicin, amikacin, tobramycin)
majorGreatly increased risk of ototoxicity (hearing loss) and nephrotoxicity. Avoid combination when possible.
Ethacrynic acid (Edecrin)
majorContraindicated — combined use carries extremely high risk of irreversible hearing loss.
Cisplatin
majorIncreased risk of kidney damage and hearing loss. Requires close monitoring.
NSAIDs (ibuprofen, naproxen, indomethacin)
moderateSignificantly reduces furosemide's diuretic and blood pressure-lowering effects. May worsen kidney function.
Lithium
moderateFurosemide-induced sodium loss prompts kidneys to retain lithium, raising blood levels and increasing toxicity risk.
Digoxin (Lanoxin)
moderateFurosemide-induced hypokalemia increases digoxin toxicity risk, including dangerous arrhythmias.
ACE inhibitors and ARBs
moderateAdditive blood pressure lowering; first-dose hypotension risk. Reduce other antihypertensive doses by 50% when adding furosemide.
Methotrexate
moderateCompetition for renal tubular secretion; furosemide may increase methotrexate levels and toxicity.
Sucralfate (Carafate)
minorReduces furosemide absorption; separate doses by at least 2 hours.
Phenytoin (Dilantin)
moderateReduces furosemide gut absorption and renal action; higher furosemide doses may be needed.
Furosemide (Lasix) is a cornerstone medication for millions of Americans managing heart failure, kidney disease, liver disease, and hypertension. It is highly effective, widely available in oral tablet form, and remarkably affordable—one of the cheapest prescription medications in the US, often available for under $5 per month with discount coupons.
Despite its availability, patients occasionally encounter local pharmacy stockouts—particularly for less common strengths (20 mg, 80 mg) or the oral solution. Injectable furosemide has faced more significant supply disruptions in the inpatient setting. Patients who cannot fill their prescription should check multiple pharmacies, ask their prescriber about alternative loop diuretics as a bridge, and consider mail-order pharmacy for reliable long-term access.
If you're struggling to find furosemide in stock near you, medfinder can contact pharmacies near your location to find which ones have your specific dosage in stock—and text you the results. Don't let a pharmacy stockout disrupt your critical diuretic therapy.
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Our medication guides are researched and written to help patients make informed decisions. All content is reviewed for accuracy and updated regularly. Learn more about our standards
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