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Generic Name: furosemide (fure-OH-se-mide)
Brand Name: Lasix

Lasix is used for:

Treating fluid build-up and swelling caused by certain conditions (eg, congestive heart failure, liver cirrhosis, kidney problems). It is also used alone or with other medicines to treat high blood pressure. It may also be used for other conditions as determined by your doctor.

Lasix is a loop diuretic. It works by helping the kidneys to remove fluid from the body.

Do NOT use Lasix if:

  • you are allergic to any ingredient in Lasix
  • you are unable to urinate
  • you are taking chloral hydrate or ethacrynic acid

Contact your doctor or health care provider right away if any of these apply to you.

Slideshow: View Frightful (But Dead Serious) Drug Side Effects

Before using Lasix:

Some medical conditions may interact with Lasix. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • if you are pregnant, planning to become pregnant, or are breast-feeding
  • if you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement
  • if you have allergies to medicines, foods, or other substances
  • if you have had a severe allergic reaction (eg, severe rash, hives, difficulty breathing, dizziness) to sulfonamide (sulfa) medicines (eg, sulfamethoxazole)
  • if you have fluid in your abdomen (ascites), hearing problems, liver problems, diabetes, high blood sugar, bladder or urinary problems, prostate problems, kidney problems, lupus, gout, abnormal blood electrolyte (eg, potassium, sodium) levels, high blood uric acid levels, low blood protein levels, or high blood cholesterol or triglyceride levels
  • if you are dehydrated, have low blood volume, or are on a low-salt (sodium) diet
  • if you eat large amounts of licorice, drink alcohol, or use laxatives on a regular basis

Some MEDICINES MAY INTERACT with Lasix. Tell your health care provider if you are taking any other medicines, especially any of the following:

  • Corticosteroids (eg, prednisone) or corticotropin (ACTH) because the risk of low blood potassium levels may be increased
  • Barbiturates (eg, phenobarbital) or narcotics (eg, codeine) because the risk of dizziness when standing may be increased
  • Aminoglycoside antibiotics (eg, gentamicin), cisplatin, or ethacrynic acid because the risk of hearing problems may be increased
  • Angiotensin-converting enzyme (ACE) inhibitors (eg, captopril) or angiotensin receptor blockers (ARBs) (eg, losartan) because the risk of low blood pressure and serious kidney problems may be increased
  • Cyclosporine because the risk of developing gout may be increased
  • Chloral hydrate because side effects, such as excessive sweating, rapid heartbeat, and changes in blood pressure, may occur
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) (eg, ibuprofen, indomethacin, naproxen) or phenytoin because they may decrease Lasix's effectiveness
  • Cephalosporin antibiotics (eg, cephalexin), digoxin, lithium, medicines for high blood pressure, methotrexate, or salicylates (eg, aspirin) because the risk of their side effects may be increased by Lasix
  • Medicines that may harm the kidney (eg, amphotericin B, tacrolimus, vancomycin) because the risk of kidney side effects may be increased. Ask your doctor if you are unsure if any of your medicines might harm the kidney

This may not be a complete list of all interactions that may occur. Ask your health care provider if Lasix may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

How to use Lasix:

Use Lasix as directed by your doctor. Check the label on the medicine for exact dosing instructions.

  • Take Lasix by mouth with or without food.
  • If you take cholestyramine, colestipol, or sucralfate, ask your doctor or pharmacist how to take them with Lasix.
  • Lasix may increase the amount of urine or cause you to urinate more often when you first start taking it. To keep this from disturbing your sleep, try to take your dose before 6 pm.
  • If you miss a dose of Lasix, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and go back to your regular dosing schedule. Do not take 2 doses at once.

Ask your health care provider any questions you may have about how to use Lasix.

Important safety information:

  • Lasix may cause dizziness or blurred vision. These effects may be worse if you take it with alcohol or certain medicines. Use Lasix with caution. Do not drive or perform other possibly unsafe tasks until you know how you react to it.
  • Lasix may cause dizziness, light-headedness, or fainting; alcohol, hot weather, exercise, or fever may increase these effects. To prevent them, sit up or stand slowly, especially in the morning. Sit or lie down at the first sign of any of these effects.
  • Diabetes patients - Lasix may affect your blood sugar. Check blood sugar levels closely. Ask your doctor before you change the dose of your diabetes medicine.
  • Tell your doctor or dentist that you take Lasix before you receive any medical or dental care, emergency care, or surgery.
  • Your doctor may also prescribe a potassium supplement while you take Lasix. Check with your doctor before you use a salt substitute or other product that has potassium in it.
  • Lasix is a strong diuretic. Using too much of Lasix can lead to serious water and electrolyte (eg, potassium, sodium) loss. It is important that you are monitored by your doctor. Tell your doctor right away if you develop symptoms of dehydration or electrolyte problems (eg, very dry mouth; unusual thirst; decreased urination; mental or mood changes, such as confusion; fast or irregular heartbeat; muscle aches, cramps, pain, spasms, or weakness; drowsiness; seizures; sluggishness; unusual restlessness, loss of appetite, or weakness; nausea and vomiting).
  • Do NOT take more than the recommended dose or use for longer than prescribed without checking with your doctor.
  • Patients who take medicine for high blood pressure often feel tired or run down for a few weeks after starting treatment. Be sure to take your medicine even if you may not feel "normal." Tell your doctor if you develop any new symptoms.
  • If you have high blood pressure, do not use nonprescription products that contain stimulants. These products may include diet pills or cold medicines. Contact your doctor if you have any questions or concerns.
  • Lasix may cause you to become sunburned more easily. Avoid the sun, sunlamps, or tanning booths until you know how you react to Lasix. Use a sunscreen or wear protective clothing if you must be outside for more than a short time.
  • Lab tests, including blood pressure, blood electrolyte (eg, potassium, sodium) levels, complete blood cell counts, and liver and kidney function, may be performed while you use Lasix. These tests may be used to monitor your condition or check for side effects. Be sure to keep all doctor and lab appointments.
  • Use Lasix with caution in the ELDERLY; they may be more sensitive to its effects, especially dehydration.
  • Caution is advised when using Lasix in CHILDREN; they may be more sensitive to its effects.
  • PREGNANCY and BREAST-FEEDING: If you become pregnant, contact your doctor. You will need to discuss the benefits and risks of using Lasix while you are pregnant. Lasix is found in breast milk. If you are or will be breast-feeding while you use Lasix, check with your doctor. Discuss any possible risks to your baby. Lasix may decrease breast milk production. Discuss any questions or concerns with your doctor.

Possible side effects of Lasix:

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most COMMON side effects persist or become bothersome:

Constipation; diarrhea; dizziness; light-headedness.

Seek medical attention right away if any of these SEVERE side effects occur:

Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue); blurred vision; calf or leg pain, swelling, redness, or tenderness; chest pain; coughing up blood; fainting; fever, chills, or sore throat; numbness, burning, or tingling sensation; red, swollen, blistered, or peeling skin; ringing in the ears or other hearing problems (eg, hearing loss); severe or persistent dizziness; severe stomach or back pain (with or without nausea or vomiting); shortness of breath; symptoms of dehydration or electrolyte problems (eg, very dry mouth; unusual thirst; decreased urination; mental or mood changes, such as confusion; fast or irregular heartbeat; muscle aches, cramps, pain, spasms, or weakness; drowsiness; seizures; sluggishness; unusual restlessness, loss of appetite, or weakness; nausea and vomiting); symptoms of high blood sugar (eg, increased thirst, hunger, or urination; confusion; drowsiness); symptoms of liver problems (eg, dark urine, loss of appetite, pale stools, severe stomach pain, yellowing of the skin or eyes); unusual bleeding or bruising; unusual tiredness or weakness; vein inflammation; yellow vision.

This is not a complete list of all side effects that may occur. If you have questions about side effects, contact your health care provider. Call your doctor for medical advice about side effects. To report side effects to the appropriate agency, please read the Guide to Reporting Problems to FDA.

If OVERDOSE is suspected:

Contact 1-800-222-1222 (the American Association of Poison Control Centers), your local poison control center, or emergency room immediately. Symptoms may include fainting; severe or persistent dizziness; symptoms of dehydration or electrolyte problems (eg, very dry mouth; unusual thirst; decreased urination; mental or mood changes, such as confusion; fast or irregular heartbeat; muscle aches, cramps, pain, spasms, or weakness; drowsiness; seizures; sluggishness; unusual restlessness, loss of appetite, or weakness; nausea and vomiting).

Proper storage of Lasix:

Store Lasix at 77 degrees F (25 degrees C). Brief storage at temperatures between 59 and 86 degrees F (15 and 30 degrees C) is permitted. Store in a tight, light-resistant container. Exposure to light may cause a slight discoloration. Do not take discolored tablets. Store away from heat and moisture. Do not store in the bathroom. Keep Lasix out of the reach of children and away from pets.

General information:

  • If you have any questions about Lasix, please talk with your doctor, pharmacist, or other health care provider.
  • Lasix is to be used only by the patient for whom it is prescribed. Do not share it with other people.
  • If your symptoms do not improve or if they become worse, check with your doctor.
  • Check with your pharmacist about how to dispose of unused medicine.

This information should not be used to decide whether or not to take Lasix or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about Lasix. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to Lasix. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using Lasix.

Issue Date: September 3, 2014
Database Edition 14.3.1.003
Copyright © 2014 Wolters Kluwer Health, Inc.

Disclaimer: This information should not be used to decide whether or not to take this medicine or any other medicine. Only your health care provider has the knowledge and training to decide which medicines are right for you. This information does not endorse any medicine as safe, effective, or approved for treating any patient or health condition. This is only a brief summary of general information about this medicine. It does NOT include all information about the possible uses, directions, warnings, precautions, interactions, adverse effects, or risks that may apply to this medicine. This information is not specific medical advice and does not replace information you receive from your health care provider. You must talk with your healthcare provider for complete information about the risks and benefits of using this medicine.

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