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This is the drug information for: FUROSEMIDE TAB 40MG

En Espanol

Read this medicine information sheet carefully each time you get this medicine filled. You must carefully read the "Consumer Information Use and Disclaimer" below in order to understand and correctly use this information.

Furosemide Tablets
Pronunciation (fyoor OH se mide)
Brand Names: US Lasix.


  • This drug is a strong fluid-lowering drug (diuretic). Sometimes too much water and electrolytes (like potassium) in the blood may be lost. This can lead to severe health problems. Your doctor will follow you closely to change the dose to match your body's needs.

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 my doctor BEFORE I take this drug?

  • If you are allergic to this drug; any part of this drug; or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.
  • If you are not able to pass urine.
  • If you are dehydrated or have electrolyte problems.
  • If you have any of these health problems: Liver problems or low blood pressure.
  • If you are taking any of these drugs: Chloral hydrate, ethacrynic acid, or lithium.
This is not a list of all drugs or health problems that interact with this drug.
Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this drug with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take this drug?

  • Tell all of your health care providers that you take this drug. This includes your doctors, nurses, pharmacists, and dentists.
  • Avoid driving and doing other tasks or actions that call for you to be alert until you see how this drug affects you.
  • To lower the chance of feeling dizzy or passing out, rise slowly if you have been sitting or lying down. Be careful going up and down stairs.
  • If you have high blood sugar (diabetes), you will need to watch your blood sugar closely.
  • Tell your doctor if you have 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.
  • If you are on a low-salt or salt-free diet, talk with your doctor.
  • If you are taking this drug and have high blood pressure, talk with your doctor before using 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.
  • Check your blood pressure as you have been told.
  • Have blood work checked as you have been told by the doctor. Talk with the doctor.
  • High cholesterol and triglyceride levels have happened with this drug. If you have high cholesterol or triglycerides, talk with your doctor.
  • You may need extra potassium. Talk with your doctor.
  • Talk with your doctor before you use alcohol, marijuana or other forms of cannabis, or prescription or OTC drugs that may slow your actions.
  • This drug may make you sunburn more easily. Use care if you will be in the sun. Tell your doctor if you sunburn easily while taking this drug.
  • Watch for gout attacks.
  • If you have lupus, this drug can make your lupus active or get worse. Tell your doctor right away if you get any new or worse signs.
  • 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 your doctor right away if you have ringing in the ears, any change in your hearing, or a feeling of fullness in your 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 doctor right away if you have signs of infection like fever, chills, or sore throat; any unexplained bruising or bleeding; or if you feel very tired or weak.
  • If you are 65 or older, use this drug with care. You could have more side effects.
  • Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

What are some side effects that I need to call my 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 doctor or get medical help right away if you have 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 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.
  • Very bad dizziness or passing out.
  • A burning, numbness, or tingling feeling that is not normal.
  • Blurred eyesight.
  • Restlessness.
  • 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 you have signs like red, swollen, blistered, or peeling skin; red or irritated eyes; sores in your 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 doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:
  • Dizziness or headache.
  • Constipation, diarrhea, upset stomach, throwing up, or decreased appetite.
  • Stomach cramps.
These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.
You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

How is this drug best taken?

Use this drug as ordered by your doctor. Read all information given to you. Follow all instructions closely.
  • This drug may cause you to pass urine more often. To keep from having sleep problems, try not to take too close to bedtime.
  • Do not take sucralfate within 2 hours before or after taking this drug.
  • Do not take if product changes color.

What do I do if I miss a dose?

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

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

  • Store at room temperature protected from light. Store in a dry place. Do not store in a bathroom.
  • 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 symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this drug, please talk with your 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.


Issue Date: November 6, 2024
Database Edition 24.4.3.006
Copyright © 2024 Wolters Kluwer Clinical Drug Information

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