furosemide
Furosemide (Lasix) is a loop diuretic, a type of water pill. Furosemide (Lasix) is used to relieve swelling from extra fluids in children and adults. This medication can also lower blood pressure, though it's not a first-choice option for this condition. Furosemide (Lasix) comes as a tablet that's taken by mouth, typically once or twice daily. It's also available as an oral solution for people who've trouble swallowing tablets. Furosemide (Lasix) will cause you to urinate more often as a side effect, so it's best to not take this medication too close to bedtime.
What is Furosemide (Lasix)?
What is Furosemide (Lasix) used for?
Swelling (edema) due to heart failure, liver problems, or kidney problems
How Furosemide (Lasix) works
Furosemide (Lasix) is a loop diuretic (water pill) that makes you urinate more. It works in the kidneys to get rid of extra water and electrolytes (like sodium and potassium), which helps ease swelling and lowers blood pressure.
Drug Facts
More on Furosemide (Lasix) essentials
Get your GoodRx coupon
What are the side effects of Furosemide (Lasix)?
Common Side Effects
- Urinating more often
- Dizziness
- Headache
- Feeling off balance when you get up suddenly
- Skin sensitive to the sun
Other Side Effects
- Vomiting
- Nausea
- Constipation or diarrhea
- Stomach cramps
- Rash
- Ringing in the ears
Serious Side Effects
- Severe dehydration and electrolyte imbalance: dry mouth, extreme thirst, weakness, low energy, drowsiness, muscle pain or cramps, fast heart beat, nausea, vomiting, not making urine
- Serious skin reaction: painful blisters, peeling skin, rash
- Severe allergic reaction: feeling lightheaded, dizziness, trouble breathing, throat closing up, swollen face, hives, nausea, vomiting, itching
Source: DailyMed
More on Furosemide (Lasix) side effects
The following side effects have also been reported
Side effects that you should report to your care team as soon as possible:
- Allergic reactions—skin rash, itching, hives, swelling of the face, lips, tongue, or throat
- Dehydration—increased thirst, dry mouth, feeling faint or lightheaded, headache, dark yellow or brown urine
- Hearing loss, ringing in ears
- High blood sugar (hyperglycemia)—increased thirst or amount of urine, unusual weakness or fatigue, blurry vision
- Low blood pressure—dizziness, feeling faint or lightheaded, blurry vision
- Low potassium level—muscle pain or cramps, unusual weakness or fatigue, fast or irregular heartbeat, constipation
Side effects that usually do not require medical attention (report to your care team if they continue or are bothersome):
- Burning or tingling sensation in hands or feet
- Constipation
- Diarrhea
- Dizziness
- Headache
Pros and cons of Furosemide (Lasix)
Pros
Starts working within an hour after you take it
Available in liquid form for children or people who have trouble swallowing pills
Available as a lower-cost generic medication
Cons
Not a good choice for people with a sulfa allergy
Might cause you to urinate in the middle of the night if you take it later in the day
Can make you more dizzy and raise your risk for falling down
Pharmacist tips for Furosemide (Lasix)
Avoid taking furosemide (Lasix) before bed so that you don't have to get up to urinate in the middle of the night. Try to take your dose in the morning or by the early afternoon.
Furosemide (Lasix) can cause dizziness in the first few days after you start it or after raising the dose. Take your time standing up to avoid dizziness or fainting from low blood pressure.
When you're taking furosemide (Lasix), your healthcare professional (HCP) might tell you to weigh yourself regularly to see how much fluid you're losing. They might change your dose of furosemide (Lasix), depending on how your body responds. Call your HCP if you have questions about your dose.
Furosemide (Lasix) can cause you to lose potassium. This can lead to muscle cramps, nausea, or vomiting. If your potassium level is low, your HCP might prescribe you potassium supplements. Make sure to tell your HCP all the medications and supplements that you're taking and get blood draws regularly so they can monitor your potassium levels.
Furosemide (Lasix) might raise your blood sugar levels. If you already have high blood sugar, your HCP might ask you to check your blood sugar levels more often. Let your healthcare team know if you notice a change from your usual numbers.
If you're pregnant or thinking of becoming pregnant, let your HCP know. It isn't known if furosemide (Lasix) is safe to take during pregnancy. While there haven't been enough studies in humans, animal studies have shown it can cause harm to mothers and unborn babies when taken during pregnancy.
Taking furosemide (Lasix) can make your skin more sensitive to the sun, which can cause you to burn more easily. Try to avoid tanning beds or spending a long time in direct sunlight. If you go outside, make sure to wear sunscreen, even when it's cloudy out. You can also wear longsleeves, long pants, and a wide-brimmed hat to protect your skin.
If you're taking the oral solution, make sure to measure your dose with the measuring device given to you at the pharmacy. Don't use household spoons because this could cause you to take the wrong dose.
More on Furosemide (Lasix) tips
Frequently asked questions about Furosemide (Lasix)
How to save using GoodRx
What are the risks and warnings for Furosemide (Lasix)?
Furosemide (Lasix) can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Dehydration and electrolyte imbalance
Risk factors: Older adults | Taking higher doses of furosemide (Lasix) | Liver problems | Not enough salt or electrolytes in your diet | Taking other medications that interact with furosemide (Lasix)
Furosemide (Lasix) is a very strong water pill. Taking too much of it can lead to serious dehydration and electrolyte imbalance, which can be life-threatening. Your risk is higher if you're taking other medications, such as laxatives (taking it regularly for a long time) or corticosteroids. Your healthcare professional (HCP) will adjust your dose based on your needs. Take furosemide (Lasix) exactly as prescribed and make sure to attend your follow-up appointments and get lab draws regularly. Get medical help right away if you notice symptoms such as dry mouth, thirst, weakness, drowsiness, muscle cramps, fast heart rate, nausea, and vomiting.
Caution in people with liver problems
People who have liver problems are more likely to have severe fluid or electrolyte imbalances, especially when first starting on furosemide (Lasix). Your HCP might start you on furosemide (Lasix) in the hospital where you can have closer monitoring. You might also be prescribed potassium supplements or other medications to prevent electrolyte imbalance.
Hearing problems
Risk factors: Current kidney problems | Taking higher than recommended dose of furosemide (Lasix) | Taking other medicines that cause hearing problems
Furosemide (Lasix) can cause ringing in the ears or even loss of hearing. This is usually more of a problem when you get furosemide (Lasix) injections in the hospital, but it can also happen when you're taking the pills at high doses. Take furosemide (Lasix) exactly as prescribed and make sure to follow up with your HCP and get lab draws regularly. Let your healthcare team know right away if you notice any new problems with your hearing.
Problems with urination
Risk factors: Difficulty emptying bladder | Enlarged prostate
Furosemide (Lasix) makes you urinate more. If you already have a hard time emptying your bladder, this can cause urine to get backed up in your bladder and lead to complications, such as infections and kidney problems. Your HCP will monitor you more closely, especially when you first start furosemide (Lasix) to make sure you're taking a safe dose.
Allergic reaction
Risk factors: Sulfa allergies
If you have allergies to other sulfa-containing medications, you might experience similar reactions with furosemide (Lasix). Make sure your healthcare team knows about all of your medication allergies, especially if they were severe. Stop taking furosemide (Lasix) and seek medical attention if you notice a rash or other signs of allergic reaction.
Gout
Risk factors: Personal or family history of gout | Existing kidney problems
Though rare, furosemide (Lasix) can raise uric acid levels in your body and cause or worsen gout. If you've had gout attacks before or you have problems with your kidneys, your risk is higher. Talk to your HCP right away if you notice that your joints are swollen, red, and painful.
Furosemide (Lasix) dosage forms
| Dosage | Quantity | Price as low as | Price per unit |
|---|---|---|---|
| 40mg/5ml | 40 ml | $5.91 | $0.15 |
Typical dosing for Furosemide (Lasix)
The dosing below are for both furosemide (Lasix) tablets and oral solution.
Swelling
Adults: The typical starting dose ranges from 20 mg to 80 mg by mouth once. Your healthcare professional (HCP) will adjust your dose depending on how your body responds to this medication. Once your HCP finds a dose that works, you typically take furosemide (Lasix) once or twice daily.
Children: Your child's pediatrician will determine the dose for your child based on their body weight. The typical starting dose is to take 2 mg/kg by mouth once. Your child's pediatrician will adjust their dose based on their body's response. The maximum recommended dose is 6 mg/kg.
High blood pressure
Adults: The typical starting dose is 40 mg by mouth twice daily. Your HCP will adjust your dose as needed.
Furosemide (Lasix) is also available in an injectable form that's given by healthcare professionals in a hospital setting.
More on Furosemide (Lasix) dosage forms
How much does Furosemide (Lasix) cost?
Furosemide (Lasix) contraindications
People whose kidneys can't make urine
What are alternatives to Furosemide (Lasix)?
Swelling (edema) due to heart failure, liver problems, or kidney problems
Swelling (edema) due to congestive heart failure, liver problems, or kidney problems
Swelling due to heart failure or kidney disease
Swelling due to liver disease (taken with other medications) - generic furosemide (Lasix) only
High blood pressure - generic furosemide (Lasix) only
What is the latest news about Furosemide (Lasix)?
Furosemide (Lasix) images
Get savings updates for Furosemide (Lasix)
Receive price alerts, news, and other messages from GoodRx about Furosemide (Lasix) and other healthcare topics and relevant savings offers.By signing up, I agree to GoodRx's Terms and Privacy Policy, and to receive marketing messages from GoodRx.
References
Best studies we foundHikma Pharmaceuticals USA Inc. (2023). Furosemide tablet; furosemide solution [package insert]. DailyMed.
Hospira, Inc. (2023). Furosemide injection, solution [package insert]. DailyMed.
Johansson, P., et al. (2016). Fluid restriction in patients with heart failure: How should we think? European Journal of Cardiovascular Nursing.
Kowalska, J., et al. (2021). Drug-induced photosensitivity–From light and chemistry to biological reactions and clinical symptoms. Pharmaceuticals.
Leading Pharma, LC. (2022). Furosemide- furosemide tablet [package insert]. DailyMed.
Precision Dose Inc. (2022). Furosemide solution [package insert]. DailyMed.
Selius, B. A., et al. (2008). Urinary retention in adults: Diagnosis and initial management. American Family Physician.
Validus Pharmaceuticals LLC. (2023). Lasix- furosemide tablet [package insert]. DailyMed.
Browse medications
View AllResearch prescriptions and over-the-counter medications from A to Z, compare drug prices, and start saving.