Furosemide

This information from Lexicomp^® explains what you need to know about this medication, including what it’s used for, how to take it, its side effects, and when to call your healthcare provider.

Brand Names: US

Furoscix; Lasix; Lasix ONYU

Brand Names: Canada

APO-Furosemide; BIO-Furosemide [DSC]; Furosemide Special; Lasix Oral; Lasix Special; MINT-Furosemide; PRO-Furosemide; TEVA-Furosemide

What is this drug used for?

• It is used to get rid of extra fluid.
• It is used to treat high blood pressure.

What do I need to tell the doctor BEFORE my child takes this drug?

All products:

• If your child is allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell the doctor about the allergy and what signs your child had.
• If your child is not able to pass urine.
• If your child is dehydrated or has electrolyte problems.
• If your child has any of these health problems: Liver problems or low blood pressure.
• If your child is taking any of these drugs: Chloral hydrate, ethacrynic acid, or lithium.

Infusor:

• If your child has an allergy to adhesive.
• If the patient is a child who weighs less than 95 lbs (43 kg).

This is not a list of all drugs or health problems that interact with this drug.

Tell the doctor and pharmacist about all of your child’s drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe to give this drug with all of your child’s other drugs and health problems. Do not start, stop, or change the dose of any drug your child takes without checking with the doctor.

What are some things I need to know or do while my child takes this drug?

All products:

• Tell all of your child’s health care providers that your child is taking this drug. This includes your child’s doctors, nurses, pharmacists, and dentists.
• Have your child avoid tasks or actions that call for alertness until you see how this drug affects your child. These are things like riding a bike, playing sports, or using items such as scissors, lawnmowers, electric scooters, toy cars, or motorized vehicles.
• To lower the chance of feeling dizzy or passing out, have your child rise slowly if your child has been sitting or lying down. Have your child be careful going up and down stairs.
• If your child has high blood sugar (diabetes), you will need to watch your child’s blood sugar closely.
• If your child is on a low-sodium or sodium-free diet, talk with your child’s doctor.
• If your child is taking this drug and has high blood pressure, talk with the doctor before giving OTC products that may raise blood pressure. These include cough or cold drugs, diet pills, stimulants, non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, and some natural products or aids.
• Have your child’s blood work and other lab tests checked as you have been told by the doctor.
• Have your child’s blood pressure checked as you have been told.
• High cholesterol and triglyceride levels have happened with this drug. If your child has high cholesterol or triglycerides, talk with the doctor.
• Your child may need extra potassium. Talk with the doctor.
• Talk with your child’s doctor before your child uses marijuana, other forms of cannabis, or prescription or OTC drugs that may slow your child’s actions.
• Alcohol may interact with this drug. Be sure your child does not drink alcohol.
• This drug may make your child sunburn more easily. Use care if your child will be in the sun. Tell your child’s doctor if your child sunburns easily while taking this drug.
• Watch for gout attacks.
• If your child has lupus, this drug can make your child’s lupus active or get worse. Tell the doctor right away if your child gets any new or worse signs.

If your child is pregnant or breast-feeding a baby:

• Talk with the doctor if your child is pregnant, becomes pregnant, or is breast-feeding a baby. You will need to talk about the benefits and risks to your child and the baby.

Infusor:

• If your child will be having an MRI or will be around an MRI machine, talk with the doctor.

What are some side effects that I need to call my child’s doctor about right away?

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your child’s doctor or get medical help right away if your child has any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Signs of fluid and electrolyte problems like mood changes, confusion, muscle pain or weakness, fast or abnormal heartbeat, severe dizziness or passing out, increased thirst, seizures, feeling very tired or weak, decreased appetite, unable to pass urine or change in the amount of urine produced, dry mouth, dry eyes, or severe upset stomach or throwing up.
• Signs of high blood sugar like confusion, feeling sleepy, unusual thirst or hunger, passing urine more often, flushing, fast breathing, or breath that smells like fruit.
• Signs of liver problems like dark urine, tiredness, decreased appetite, upset stomach or stomach pain, light-colored stools, throwing up, or yellow skin or eyes.
• Signs of kidney problems like unable to pass urine, change in how much urine is passed, blood in the urine, or a big weight gain.
• Signs of a pancreas problem (pancreatitis) like very bad stomach pain, very bad back pain, or very bad upset stomach or throwing up.
• Severe dizziness or passing out.
• A burning, numbness, or tingling feeling that is not normal.
• Blurred eyesight.
• Restlessness.
• Hearing problems like decreased hearing and loss of hearing have happened with this drug. Sometimes this may go away but sometimes it may not. Call the doctor right away if your child has ringing in the ears, any change in hearing, or a feeling of fullness in the ears.
• Low blood cell counts have happened with this drug. If blood cell counts get very low, this can lead to bleeding problems, infections, or anemia. Call your child’s doctor right away if your child has signs of infection like fever, chills, or sore throat; any unexplained bruising or bleeding; or if your child feels very tired or weak.
• Severe skin reactions may happen with this drug. These include Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and other serious reactions. Sometimes, body organs may also be affected. These reactions can be deadly. Get medical help right away if your child has signs like red, swollen, blistered, or peeling skin; red or irritated eyes; sores in the mouth, throat, nose, eyes, genitals, or any areas of skin; fever; chills; body aches; shortness of breath; or swollen glands.

What are some other side effects of this drug?

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your child’s doctor or get medical help if any of these side effects or any other side effects bother your child or do not go away:

All products:

• Dizziness or headache.
• Constipation, diarrhea, upset stomach, throwing up, or decreased appetite.
• Stomach cramps.

Infusor:

• Swelling, warmth, or redness where this drug was given.
• Bruising, soreness, or short-term pain where this drug was given.

These are not all of the side effects that may occur. If you have questions about side effects, call your child’s doctor. Call your child’s doctor for medical advice about side effects.

You may report side effects to your national health agency.

How is this drug best given?

Give this drug as ordered by your child’s doctor. Read all information given to you. Follow all instructions closely.

All oral products:

• This drug may cause your child to pass urine more often. To keep your child from having sleep problems, try not to give too close to bedtime.
• Do not give sucralfate within 2 hours before or after giving this drug.
• Do not give if product changes color.

Liquid (solution):

• Measure liquid doses carefully. Use the measuring device that comes with this drug. If there is none, ask the pharmacist for a device to measure this drug.

Injection:

• It is given as a shot into a muscle or vein.

Infusor:

• It is given into the fatty part of the skin on the belly area between the bottom of the ribcage and the top of the belt line.
• If you will be giving this drug to your child, your child’s doctor or nurse will teach you how to give it.
• Be sure you know how to use this drug. Read the instructions for use that come with this drug. If there are no instructions for use or you have any questions about how to use this drug, talk with the doctor or pharmacist.
• Do not use this drug somewhere you will not be able to hear or see the alarm if it goes off.
• This infusion takes about 5 hours. Have your child limit physical activity and try to avoid bending while your child has this drug on.
• Do not let your child use this drug within 12 inches of a mobile phone, tablet, computer, or wireless device like a TV remote, computer keyboard, or mouse.
• Do not let your child wear this drug in a car or on a plane. If your child needs to be in a car or on a plane, talk with the doctor.
• This drug will cause your child to pass urine more often. Be sure your child stays near a bathroom for at least 8 hours after starting this drug. To keep from having sleep problems, try not to give too close to bedtime. If your child does not pass urine more often, call the doctor.
• Wash your hands before and after use.
• Do not open until you are ready to use.
• Do not touch the start button until you have put this device on your child’s skin.
• Do not give into skin that is irritated, tender, bruised, red, scaly, hard, scarred, or has stretch marks.
• Do not put on skin with a lot of hair. You may clip or shave any hair at the site you will be using.
• Do not put on skin where your child has just used creams, oils, lotions, or other skin products.
• Do not put the infusor where a belt, waistband, or other type of clothing may rub against or push it off your child’s skin.
• Move the site where you give this drug as you were told by the doctor.
• Do not use this drug if it has been dropped or if it is broken.
• Do not use if the solution is cloudy, leaking, or has particles.
• This drug is colorless to a faint yellow. Do not use if the solution changes color.
• Do not let the device get wet from water or any other fluid like blood or this drug. Do not let your child shower, take a bath, swim, or do activities that cause sweating while your child wears this drug.
• Do not let your child take the infusor off until the dose has finished. If there is an emergency, if the infusor falls off, or the infusor has an error, follow the directions in the instructions for use. If you are not sure what to do, call the doctor right away.
• Some products have a reusable infusor for use with cartridges that can only be used 1 time. Some products may only be used 1 time. Be sure you know if your child’s device can be reused.
• When throwing away single use devices or parts of a device that cannot be reused, put them in a needle/sharp disposal box. When the box is full, follow all local rules for getting rid of it. Talk with a doctor or pharmacist if you have any questions.
• Do not use other medicines or other cartridges with the infusor.

What do I do if my child misses a dose?

All oral products:

• Give a missed dose as soon as you think about it.
• If it is close to the time for your child’s next dose, skip the missed dose and go back to your child’s normal time.
• Do not give 2 doses at the same time or extra doses.

Injection and Infusor:

• Call your child’s doctor to find out what to do.

How do I store and/or throw out this drug?

All oral products:

• Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.

Liquid (solution):

• Do not freeze.

Infusor:

• Store at room temperature. Do not refrigerate or freeze.
• Store in the outer carton to protect from light.

Injection:

• If you need to store this drug at home, talk with your child’s doctor, nurse, or pharmacist about how to store it.

All products:

• Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
• Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

General drug facts

• If your child’s symptoms or health problems do not get better or if they become worse, call your child’s doctor.
• Do not share your child’s drug with others and do not give anyone else’s drug to your child.
• Some drugs may have another patient information leaflet. If you have any questions about this drug, please talk with your child’s doctor, nurse, pharmacist, or other health care provider.
• If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Consumer Information Use and Disclaimer

This generalized information is a limited summary of diagnosis, treatment, and/or medication information. It is not meant to be comprehensive and should be used as a tool to help the user understand and/or assess potential diagnostic and treatment options. It does NOT include all information about conditions, treatments, medications, side effects, or risks that may apply to a specific patient. It is not intended to be medical advice or a substitute for the medical advice, diagnosis, or treatment of a health care provider based on the health care provider’s examination and assessment of a patient’s specific and unique circumstances. Patients must speak with a health care provider for complete information about their health, medical questions, and treatment options, including any risks or benefits regarding use of medications. This information does not endorse any treatments or medications as safe, effective, or approved for treating a specific patient. UpToDate, Inc. and its affiliates disclaim any warranty or liability relating to this information or the use thereof. The use of this information is governed by the Terms of Use, available at https://www.wolterskluwer.com/en/know/clinical-effectiveness-terms.

Last Reviewed Date

2026-01-15

Copyright

© 2026 UpToDate, Inc. and its affiliates and/or licensors. All rights reserved.