• If you are allergic to any medicines, dyes, additives, or foods. People who are allergic to sulfonamide drugs (sulfadiazine, sulfamethoxazole, etc.) may also be allergic to furosemide.

• If you have a history of serious kidney disease or liver disease, such as cirrhosis. You may be more likely to have side effects from this drug.

• If you have a history of diabetes, gout, or systemic lupus erythematosus (SLE). These conditions may become worse while taking this drug.

• If you have any other medical conditions such as heart disease, congestive heart failure, lung disease, or infections. You may need closer monitoring of these conditions while being treated.

• If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. It is not known if this drug might cause problems if either the male or female is taking it at the time of conception or during pregnancy. If you are sexually active while taking this drug, you should use some kind of birth control during treatment. It is important to check with your doctor about what kinds of birth control can be used with this medicine. This drug should be used during pregnancy only if the potential benefit is thought to justify the potential risk to the fetus.

• If you are breast-feeding. This drug may pass into breast milk and affect the baby. Talk with your doctor about the possible risks of breast-feeding while taking this drug.

• About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs.

This drug may raise the risk of hearing loss if taken with ethacrynic acid, amphotericin B, or aminoglycoside antibiotics (streptomycin, tobramycin, amikacin, neomycin, gentamicin, etc.). This drug could cause blood pressure to drop too low if used along with certain blood pressure or heart medicines.

This drug may affect the kidneys if used along with high doses of non-steroidal anti-inflammatory drugs (NSAIDS) such as aspirin or ibuprofen.

Furosemide should be used with caution in patients taking lithium, as it may raise blood lithium levels.

This drug can lower blood levels of potassium, and must be used carefully if other drugs affecting potassium levels are also being taken.

Use of the ulcer drug sucralfate may make furosemide less effective.

There may be other drug interactions as well. Check with your doctor, nurse, or pharmacist about all of your medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

If you are taking furosemide to help remove calcium from the blood, you will likely get an IV infusion of salt water (normal saline) at the same time, which will help take calcium out of the body.

Your doctor may advise you to eat a diet high in potassium or take potassium supplements, or you may be given potassium or other electrolytes in your IV fluid. This is to replace what is lost in the urine.

Your doctor will also test your blood throughout your treatment, looking for possible effects of the drug on blood electrolyte levels. Based on the test results, your doctor may need to change your dose of this drug.

Because it causes the body to get rid of fluid, this drug may cause dehydration or a drop in blood pressure. This may cause you to fell dizzy, lightheaded, or even faint if you sit up or stand up too quickly. Changing position slowly can reduce the risk of these problems.

This drug may make you very sensitive to sunlight. Do not spend long periods in the sun until you know how your skin is reacting to sunlight. Your doctor may advise you to avoid being outdoors between the hours of 10 and 4, use sunscreen, and/or to wear sunglasses, a hat, and protective clothes when outside, even on hazy days.

People with diabetes should be aware that furosemide may raise blood glucose levels.

People with a history of gout should be cautious when taking this medicine. This drug may raise your uric acid level and your risk of having an attack.

In some cases this drug may affect your hearing, especially if taken in high doses or if used along with other drugs that can affect hearing. Tell your doctor right away if you notice any change in your hearing, including ringing in your ears.

• frequent urination
• feeling dizzy or lightheaded when sitting up or standing (due to blood pressure changes)*

• loss of electrolytes (potassium, sodium, chloride, magnesium, calcium) from the blood, which shows up on lab tests (Your doctor will explain the importance of these findings, if any.)*
• headache
• loss of appetite
• stomach cramps
• diarrhea
• increased uric acid in the blood (may raise the risk of gout attacks)*
• increased blood glucose levels*

• ringing in the ears (tinnitus) or hearing loss, especially if high doses are used*
• vision changes (blurred vision, yellowing of vision)
• blood test results showing the drug may be affecting your pancreas (Your doctor will explain the importance of these findings, if any.)*
• increased sensitivity to sunlight*
• allergic reaction (hives, skin rash, or itching)

*See "Precautions" section for more detailed information.