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Furosemide

Generic Name: furosemide (oral/injection) (fur OH se mide)
Brand Names: Lasix, Diaqua-2, Lo-Aqua

Medically reviewed by P. Thornton, DipPharm Last updated on Jul 3, 2019.

What is furosemide?

Furosemide is a loop diuretic (water pill) that prevents your body from absorbing too much salt. This allows the salt to instead be passed in your urine.

Furosemide is used to treat fluid retention (edema) in people with congestive heart failure, liver disease, or a kidney disorder such as nephrotic syndrome.

Furosemide is also used to treat high blood pressure (hypertension).

Important Information

You should not use furosemide if you are unable to urinate.

Do not take more than your recommended dose. High doses of furosemide may cause irreversible hearing loss.

Before using furosemide, tell your doctor if you have kidney disease, enlarged prostate, urination problems, cirrhosis or other liver disease, an electrolyte imbalance, high cholesterol, gout, lupus, diabetes, or an allergy to sulfa drugs.

Tell your doctor if you have recently had an MRI (magnetic resonance imaging) or any type of scan using a radioactive dye that is injected into your veins. Do not take more of this medication than is recommended.

If you are being treated for high blood pressure, keep using this medication even if you feel fine. High blood pressure often has no symptoms.

Before taking this medicine

You should not use furosemide if you are allergic to it, or if you are unable to urinate.

Tell your doctor if you have ever had:

  • kidney disease;

  • enlarged prostate, bladder obstruction, urination problems;

  • cirrhosis or other liver disease;

  • an electrolyte imbalance (such as low levels of potassium or magnesium in your blood);

  • gout;

  • lupus;

  • diabetes; or

  • a sulfa drug allergy.

Tell your doctor if you have an MRI (magnetic resonance imaging) or any type of scan using a radioactive dye that is injected into your veins. Both contrast dyes and furosemide can harm your kidneys.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

It may not be safe to breastfeed while using this medicine. Ask your doctor about any risk. Furosemide may slow breast milk production.

How should I take furosemide?

Take furosemide exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

Furosemide oral is taken by mouth. The injection is injected into a muscle or given as an infusion into a vein. A healthcare provider will give you this injection if you are unable to take the medicine by mouth.

You may receive your first dose in a hospital or clinic setting if you have severe liver disease.

Do not take more than your recommended dose. High doses of furosemide may cause irreversible hearing loss.

Measure liquid medicine carefully. Use the dosing syringe provided, or use a medicine dose-measuring device (not a kitchen spoon).

Furosemide doses are based on weight in children. Your child's dose needs may change if the child gains or loses weight.

Furosemide will make you urinate more often and you may get dehydrated easily. Follow your doctor's instructions about using potassium supplements or getting enough salt and potassium in your diet.

Your blood pressure will need to be checked often and you may need other medical tests.

If you have high blood pressure, keep using this medicine even if you feel well. High blood pressure often has no symptoms. You may need to use blood pressure medicine for the rest of your life.

If you need surgery, tell the surgeon ahead of time that you are using this medicine.

Store at room temperature away from moisture, heat, and light. Throw away any unused oral liquid after 90 days.

What happens if I miss a dose?

Furosemide is sometimes used only once, so you may not be on a dosing schedule. If you are using the medication regularly, take the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not take two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include feeling very thirsty or hot, heavy sweating, hot and dry skin, extreme weakness, or fainting.

What should I avoid while taking furosemide?

Avoid getting up too fast from a sitting or lying position, or you may feel dizzy.

Avoid becoming dehydrated. Follow your doctor's instructions about the type and amount of liquids you should drink while you are taking furosemide.

Drinking alcohol with furosemide can cause side effects.

If you have high blood pressure, ask a doctor or pharmacist before taking any medicines that can raise your blood pressure, such as diet pills or cough-and-cold medicine.

Furosemide side effects

Get emergency medical help if you have signs of an allergic reaction to furosemide (hives, difficult breathing, swelling in your face or throat) or a severe skin reaction (fever, sore throat, burning in your eyes, skin pain, red or purple skin rash that spreads and causes blistering and peeling).

To make sure this medicine is safe for you, tell your doctor if you have:

  • a light-headed feeling, like you might pass out;

  • ringing in your ears, hearing loss;

  • muscle spasms or contractions;

  • pale skin, easy bruising, unusual bleeding;

  • high blood sugar - increased thirst, increased urination, dry mouth, fruity breath odor;

  • kidney problems - little or no urination, swelling in your feet or ankles, feeling tired or short of breath;

  • signs of liver or pancreas problems - loss of appetite, upper stomach pain (that may spread to your back), nausea or vomiting, dark urine, jaundice (yellowing of the skin or eyes); or

  • signs of an electrolyte imbalance - dry mouth, thirst, weakness, drowsiness, feeling jittery or unsteady, vomiting, irregular heartbeats, fluttering in your chest, numbness or tingling, muscle cramps, muscle weakness or limp feeling.

Common furosemide side effects may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect furosemide?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective.

If you also take sucralfate, take your furosemide dose 2 hours before or 2 hours after you take sucralfate.

Tell your doctor about all your other medicines, especially:

This list is not complete. Other drugs may interact with furosemide, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use furosemide only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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