Lasix is a loop diuretic that prevents your body from absorbing too much salt. This allows the salt to instead be passed in your urine.

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

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

Important information

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

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

Before using Lasix, 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. High doses of furosemide may cause irreversible hearing loss. 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.

How should I take Lasix?

Take Lasix exactly as prescribed by your doctor. Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

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

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

Lasix 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.

While using Lasix, you may need frequent blood tests.

Keep using this medicine as directed, 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 Lasix.

Store at room temperature away from moisture, heat, and light.

What other drugs will affect Lasix?

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 current medicines and any you start or stop using, especially:

chloral hydrate;
lithium;
phenytoin;
cancer medicine, such as cisplatin;
heart or blood pressure medicine; or
another diuretic, especially ethacrynic acid.