Furosemide (Oral)

Furosemide is a water pill which works to reduce fluid retention and control high blood pressure when used in conjunction with other medicines or lifestyle changes.

Overview

Furosemide is a diuretic (water pill) which works to control high blood pressure and edema (fluid retention) caused by a variety of medical conditions, including heart disease, kidney disease and liver disease. The medicine acts on the kidneys to force unneeded salt and water to exit the body via urination. It can help to reduce the risk of heart attack, stroke, kidney failure and other conditions caused by high blood pressure.

Usually, furosemide is used in combination with other medicines or lifestyle changes to reduce high blood pressure. It only works to reduce blood pressure for as long as the medicine is being taken, and it is therefore important for patients to work to reduce their blood pressure naturally and permanently. This can be done by losing weight if overweight or obese, eating a diet which is low in salt and fat, exercising regularly, not smoking, and drinking alcohol in moderation.

When furosemide is taken orally it is available in two dosage forms: tablet and solution. It is only available with a doctor's prescription, and is known by the brand names Furocot and Lasix.

Conditions Treated?

  • High blood pressure
  • Edema

Type Of Medicine?

  • Diuretic

Side Effects

Furosemide can cause unwanted side effects as well as its needed effects. Although it is unlikely that all of these side effects will occur, patients should familiarize themselves with them so that they can recognize the serious ones and seek medical attention where necessary. Patients who are unsure as to the severity of a side effect should consult their doctor.

The following side effects require immediate medical attention:

Rare

O Chills
O Fever
O Chest pain
O Cough or hoarseness
O Sore throat
O Swollen or painful glands
O Tight chest
O Shortness of breath
O Wheezing
O General tiredness or weakness
O Headache
O Pain in lower back or side
O Painful or difficult urination
O Ulcers, sores or white spots on lips or in mouth
O Unusual bruising or bleeding

Incidence unknown

O Pain in back or legs
O Joint or muscle pain
O Pain in stomach, side or abdomen, possibly radiating to back
O Swelling of feet or lower legs
O Bloating
O Indigestion
O Nausea or vomiting
O Vomiting of blood
O Constipation
O Diarrhea
O Clay-colored stools
O Black, tarry stools
O Blood in urine or stools
O Darkened urine
O Cloudy colored urine
O Greatly reduced frequency of urination or amount of urine
O Bleeding gums
O Coughing up blood
O Nose bleeds
O Pale skin
O Pinpoint red spots on skin
O Red, swollen skin
O Peeling, loosening or blistering of the skin
O Cracks in the skin
O Flushed, dry skin
O Skin rash
O Itching
O Yellow skin or eyes
O Blurred vision
O Ringing, buzzing or other unexplained noise in ears
O Hearing loss
O Burning, numbness, crawling, itching or tingling sensations
O Changes in skin color, pain, swelling or tenderness in foot or leg
O Sweating
O Cold sweats
O Dry mouth
O Fruit-like breath odor
O Increased thirst
O Increased hunger
O Loss of appetite
O Unusual weight loss
O Dizziness, faintness or lightheadedness when arising
O Confusion
O Difficulty breathing
O Fast heartbeat

The following side effects are minor and don't require medical attention unless they become very severe or prolonged. They may dissipate when your body adjusts to the medicine. If you have questions about them, consult your doctor.

  • Hives or welts
  • Increased skin sensitivity to sunlight
  • Severe sunburn
  • Redness or other skin discoloration
  • Muscle spasms
  • Weakness
  • Sensation of spinning
  • Feeling of self or surroundings constantly moving

This may not be an exhaustive list of all side effects that could be experienced while taking furosemide. If you notice any others not listed here, consult your doctor immediately. You could also report new side effects to the FDA, or your doctor may do this on your behalf.

Signs of overdose

If you think you may have taken too much furosemide, consult your doctor immediately or call your local poison control center. If the patient loses consciousness, has a seizure or has trouble breathing, call 911. If you notice any other symptoms of overdose listed below, seek immediate medical attention:

  • Decreased urination
  • Drowsiness
  • Mood changes
  • Irritability
  • Increased heartbeat
  • Irregular heartbeat
  • Weak pulse
  • Rapid breathing
  • Muscle cramps
  • Seizures
  • Trembling
  • Numbness, tingling, pain or weakness in hands, feet or lips
  • Weakness and heaviness in legs
  • Extreme thirst
  • Wrinkled skin
  • Sunken eyes

Dosage

The amount of furosemide you take will vary depending on the severity of your blood pressure or edema, and other factors personal to you such as your weight and medical history. Your doctor may gradually increase your dose following routine appointments to check how well the drug is working. The following dosages are averages only; always follow your doctor's instructions regarding the amount of furosemide you take, the number of times you take it in a day, and how long you take it for.

For edema:

  • Adults: 20 to 60 mg at first, taken either once each day or divided into two doses each day, and increased as necessary.
  • Children: Dose determined on body weight, usually starting at 2 mg per kilogram of body weight per day, with a maximum dose of 6 mg per kilogram of body weight.

For high blood pressure:

  • Adults: 40 mg at taken twice each day, and increased as necessary.
  • Children: Use and dose determined by doctor.

It is very important that you continue taking furosemide until your doctor tells you otherwise, even if you feel well. High blood pressure does not always cause noticeable symptoms, so it is impossible to know whether your blood pressure is at a healthy level without a doctor's assessment. When you stop taking furosemide, your blood pressure will quickly return to elevated levels unless you have made adequate lifestyle changes to reduce it. Your doctor will tell you when it is the right time to stop taking furosemide.

How to take furosemide

Furosemide should be taken by mouth at around the same time(s) every day. Tablets should be swallowed whole without being crushed, chewed or broken. The solution should be measured out using the marked oral syringe, measuring spoon, or medicine cup provided with it. You could ask your pharmacy for a dose-measuring device if you are not provided with one. You should always carefully measure furosemide solution to ensure you are not taking too much or too little.

If you also take sucralfate (Carafate), you should take it either two hours before or two hours after taking furosemide. This is because it may stop furosemide from working correctly.

Furosemide may make you urinate more frequently. You may choose to take the medicine during the day rather than at nighttime so that your sleep is not disturbed by frequent trips to the bathroom.

Missed dose

If you miss a dose of furosemide, take it as soon as possible. However, if it is almost time for the next dose, skip the missed dose and continue with your usual dosing schedule. Do not double doses of furosemide if you have missed a dose, as doing so could increase the risk of harmful side effects.

Interactions

Furosemide can interact with a wide variety of medicines. It is very important that you tell your doctor about all the medicines you take, including those which are prescribed to you and those purchased over the counter, as well as any herbal supplements or vitamins you take. You may wish to keep a list of your medicines which you can present to every doctor or healthcare professional you see so that they can check for harmful interactions.

It is particularly important to mention the following types of medicines:

  • Aminoglycoside antibiotics, eg:

O Amikacin

O Gentamicin (Garamycin)

O Tobramycin (Bethkis, Tobi)

  • Angiotensin-converting enzyme (known as ACE) inhibitors, such as:

O Benazepril (Lotrel, Lotensin)

O Captopril (Capoten)

O Fosinopril

O Lisinopril (Zestoretic, Prinzide)

O Moexipril (Uniretic, Univasc)

O Perindopril (Aceon)

O Quinapril (Accupril, Accuretic)

O Ramipril (Altace)

O Trandolapril (Tarka, Mavik)

  • Angiotensin II receptor antagonists (known as ARBs), eg.:

O azilsartan (Edarbi, Edarbyclor)

O Candesartan (Atacand HCT, Atacand)

O Eprosartan (Teveten, Teveten HCT)

O Irbesartan (Avalide, Avapro)

O Losartan (Hyzaar, Cozaar,)

O Olmesartan (Benicar, Azor, Benicar HCT)

O Telmisartan (Micardis)

O Valsartan (Diovan, Exforge)

  • Aspirin
  • Barbiturates, such as:

O Phenobarbital

O Secobarbital (Seconal)

  • Corticosteroids, such as:

O Betamethasone (Celestone)

O Budesonide (Entocort)

O Cortisone (Cortone)

O Dexamethasone (Baycadrom, Decadron, Dexpak, Dexasone)

O Fludrocortisone (Floriner)

O Hydrocortisone (Hydrocortone, Cortef)

O Methylprednisolone (Meprolone, MethylPREDNISolone, Medrol)

O Prednisone (Sterapred, Meticorten, Deltasone)

O Prednisolone (Prelone)

O Triamcinolone (Azmacort, Aristocort)

  • Cyclosporine (Neoral, Sandimmune, Gengraf)
  • Cisplatin (Platinol)
  • Diabetes medicines
  • Digoxin (Lanoxin)
  • Ethacrynic acid (Edecrin)
  • High blood pressure medicines
  • Indomethacin (Indocin)
  • Lithium (Lithobid)
  • Laxatives
  • Methotrexate (Trexall)
  • Pain medicines
  • Probenecid (Probalan, Probenemid)
  • Phenytoin (Dilantin, Phenytek)

You should also know that if you are taking sucralfate (brand name Carafate) to treat active duodenal ulcers, it should be taken either two hours before or two hours after furosemide. This is because it may make furosemide less effective if taken at the same time.

Be sure to tell your doctor if you have had radioactive dye injected into your veins recently. This is often used during MRI (magnetic resonance imaging) scans.

Warnings

Interactions With Medical Conditions

Furosemide may be unsuitable for patients with certain preexisting medical conditions. It is very important that your doctor knows your full medical history so that they can decide whether furosemide is safe for you. This includes conditions you currently suffer from, and those you have suffered from in the past.

Patients with anuria (inability to pass urine) should not use this drug in any circumstances.

The following conditions may be worsened by furosemide. Your doctor may choose not to prescribe furosemide, or they may simply administer lower doses and/or request that you are monitored more closely throughout treatment.

  • Anemia
  • Hyperuricemia (high uric acid in blood)
  • Hypocalcemia (low calcium in blood)
  • Hypochloremic alkalosis (low chlorine in blood)
  • Hypokalemia (low potassium in blood)
  • Hypomagnesemia (low magnesium in blood)
  • Hyponatremia (low sodium in blood)
  • Hypotension (low blood pressure)
  • Hypovolemia (low blood volume)
  • High cholesterol or triglycerides
  • Diabetes mellitus
  • Hearing problems
  • Tinnitus (ringing in ears)
  • Severe liver disease (such as cirrhosis)
  • Systemic lupus erythematosus (SLE)
  • Bladder problems involving urination
  • Bladder emptying disorders, such as:

O Enlarged prostate

O Narrow urethra

  • Dehydration
  • Gout

The following conditions may worsen side effects associated with furosemide. Your doctor may choose not to prescribe furosemide, or they may monitor you more closely to check for serious side effects.

  • Hypoproteinemia (low protein in the blood) caused by a kidney problem
  • Radiocontrast nephropathy (kidney problem)

Patients with severe kidney disease may also be unable to take furosemide due to slower removal of the drug from the body. Essentially, if the kidneys take longer to process and remove a drug, the effects of the drug become more potent. For patients with mild to moderate kidney disease, furosemide may be safe, but for those with severe kidney disease lower dosages may be administered and they may be monitored more closely.

Alcohol and tobacco

Although alcohol and tobacco do not directly interact with furosemide, they can contribute to high blood pressure. Patients are usually advised to drink alcohol moderately and stop smoking when they start taking furosemide. If you think you may have trouble cutting down on alcohol or quitting smoking, ask your doctor for advice.

Allergies

You may not be able to take furosemide if you have had a reaction to it, to drugs like it, or to sulfa drugs in the past. Examples of sulfa drugs are sulfamethoxazole, sulfasalazine, sulfisoxazole, Azulfidine, Bactrim, Gantrisin, and Septra.

Make sure your doctor knows about all the allergies you suffer from or have suffered from in the past so that they can check you're not allergic to any of the ingredients in furosemide.

If you notice any of the following signs of allergy when taking furosemide, consult your doctor immediately:

  • Rash
  • Hives
  • Itching
  • Swelling of face, lips, tongue or throat
  • Wheezing
  • Difficulty breathing

Pediatric use

Furosemide appears to be just as safe and effective in children as it is in adults. However, when used to reduce high blood pressure, the use and dose of furosemide should be determined by a doctor. The drug is used with caution in premature babies since they are more likely to develop kidney problems when taking the drug.

Geriatric use

There is no evidence to suggest that furosemide is any less safe or effective in elderly patients than in younger adults. However, since elderly patients are more likely to have age-related kidney, liver or heart problems, the drug is used with greater caution. Lower dosages may be administered to elderly patients initially and increased if it appears safe to do so.

Pregnancy and breastfeeding

Furosemide is a pregnancy category C drug, which means it should only be used during pregnancy if the benefits of the drug outweigh potential risks to the fetus. Animal studies have demonstrated potential harm to the fetus, and there are not enough controlled human studies to demonstrate the safety of the drug for pregnant women. If you become pregnant while taking furosemide, tell your doctor straight away.

Furosemide is excreted in human breast milk, but it is unknown what effects the drug could have on nursing infants. Furthermore, furosemide could slow breast milk production. For these reasons, the drug should be avoided while breastfeeding, or breastfeeding should be stopped while taking furosemide.

Storage

Furosemide tablets and solution should both be stored at room temperature and away from heat, direct light, moisture, and freezing temperatures. Store the medicine in the container it was provided in with the lid tightly closed at all times when not in use. Keep it out of sight and reach of children and pets.

Do not keep expired or unused furosemide. Instead, ask your healthcare provider how to safely dispose of it. Do not flush it down the toilet or throw it in the trash as it may come to harm other people. There may be a local medicine take-back program offered by your pharmacy, healthcare provider, or local trash or recycling department that you could use.

Summary

Furosemide is a diuretic which can be used to treat edema (fluid retention) caused by conditions like heart, liver and kidney disease, and high blood pressure when used in combination with other medicines and/or lifestyle changes. People who are prescribed furosemide to control high blood pressure may need to follow a low-salt, low-fat diet, lose excess weight, quit smoking, and reduce alcohol intake to get the best results from furosemide.

This drug is designed to be taken orally and is available in tablet and solution dosage forms. Usually, patients begin with low doses which are gradually increased where necessary after monitoring of their condition. The drug is usually taken either once or twice each day, and since it increases the rate of urination, it is best taken either earlier in the day or several hours before bedtime so that sleep is not disturbed by trips to the bathroom.

Furosemide commonly causes increased skin sensitivity to sunlight, redness or discoloration of skin, mild dizziness, and weakness among other minor side effects. These do not require medical attention unless they become very severe or prolonged. Patients who experience chest pain, fever, breathing problems, severe skin rashes or other skin problems, muscle or joint pain or spasms, vomiting, unusual bleeding, or problems with urination should consult their doctor immediately or visit the emergency room.

Many drugs can interact with furosemide, particularly aminoglycoside antibiotics, ACE inhibitors, ARBs, barbiturates, corticosteroids, laxatives, other blood pressure medicines, and pain medicines. It's important that patients tell their doctor about all the medicines they take, including over-the-counter treatments and herbal supplements or vitamins. It's also vital that patients let their doctor know if they recently had an MRI scan in which radioactive dye was injected. Patients who take sucralfate (Carafate) should take it at least 2 hours before or after furosemide to ensure that it does not stop furosemide from working correctly.

Children, except preterm infants, are generally safe to take furosemide. Elderly patients can also take the drug, but they may be more likely to have kidney problems which means caution is necessary. Pregnant and breastfeeding women are not recommended to take furosemide.

Furosemide should never be taken by patients with anuria (inability to urinate). The drug could worsen anemia, electrolyte imbalances, diabetes, hearing problems and tinnitus, lupus, gout, and conditions involving urination and bladder emptying such as enlarged prostate or narrow urethra. The drug should also be used with caution in patients with severe kidney disease, because this can cause slower removal of drugs from the body, which may increase the risk of side effects.