Side Effects of Furosemide (Lasix)

Furosemide or Lasix is a diuretic medicine, also known as a “water pill” that removes excess body fluid. While it can be an effective treatment for edema, kidney disease, and high blood pressure, it can also come with potential side effects that patients should be aware of. This blog will give you a closer look at the potential side effects of furosemide and what precautions to take to minimize the risks.

What is Furosemide?

Furosemide, an orally available tablet, is a prescribed medication sold under the trade name Lasix. It is a looping diuretic (water pill) that keeps the body from absorbing excessive amounts of salt. It permits the salt to be excreted in the urine instead. Moreover, it treats water retention (edema) in patients suffering from congestive heart failure, liver illness, or kidney problems such as nephrotic syndrome. Furosemide is also prescribed to treat hypertension.

Side Effects of Furosemide (Lasix)

Furosemide can have mild to severe adverse effects which can vary based on the following:

• Age

• Additional health issues 

• Extra drugs you may be taking

Common Side Effects:

The following are the common, unwanted effects of furosemide:

1. Dehydration

• If used in large doses, furosemide can cause excessive urination which leads to dehydration.

• Dehydration symptoms include dry mouth, thirst, decreased urine, reduced tears, and lowered sweating. 

• To avoid these symptoms, ensure you are consuming plenty of water. 

2. High Blood Sugar Levels

• Furosemide may impair blood sugar management in diabetics. So, people need to discuss it with a doctor before taking this medicine.

• By interrupting the speed of transport of glucose in adipose tissues and reducing the rate of phosphorylation and glycolysis of glucose in muscles, it increases blood sugar levels.

3. Electrolyte Imbalance

• This medicine can alter electrolyte levels such as sodium, potassium, calcium, fluoride, and magnesium.

• This can lead to symptoms like muscle cramps, weakness, rapid heartbeats, dry mouth, vomiting, nausea, and lethargy. 

4. Low Blood Pressure

• As furosemide helps get rid of water and salt via urine, it leads to less fluid in the tissues.

• When there is less fluid in the blood, it reduces blood pressure levels. 

5. Frequent Urination

• Being a diuretic, furosemide helps to get rid of excess water and salt through urine.

• This increases the amount of urine, leading to frequent urination. 

6. Dizziness

• Due to the fluctuations in blood pressure and fluid loss after taking furosemide, you can feel dizzy.

• This can make you faint when you stand up. So, stand slowly. 

Note: If you experience any of these symptoms that last for longer, report them to your doctor.

Severe Side Effects:

Though rare, furosemide can sometimes lead to severe side effects that need immediate medical attention. The following are the furosemide adverse effects:

1. Hearing Loss

• Furosemide can cause damage to the stria vascularis, a specific tissue in the inner ear that helps produce the fluid for protecting the hair cells, which are crucial for hearing.

• The damage can prevent the hair cells from converting vibration signals into electrical signals, causing hearing loss.

2. Kidney Function Failure

• By reducing the blood flow to the kidneys due to reduced blood volume, furosemide can lower the supply of oxygen and nutrients to the kidneys, thus, causing damage to the kidneys.

• Moreover, it can change the balance of electrolytes such as sodium, potassium, magnesium, and calcium, impairing kidney function. 

3. Severe Allergic Reactions

• According to research, long use of furosemide can rarely lead to severe allergic reactions.

• The reactions may come with symptoms like breathing issues, racing heart, trouble swallowing, swollen lymph nodes, or swelling in the throat, tongue, mouth, or lips.

4. Gout Attack

• Furosemide can interrupt the ability of the kidneys to eliminate uric acid, which leads to the accumulation of uric acid in the blood.

• The accumulated uric acid then forms the uric acid crystal in the joints, which causes gout with symptoms like pain, swelling, and stiffness in the joint.

Who Should Not Take Furosemide?

Furosemide may not be suitable for everyone. So, discuss it with your doctor if you have:

• allergic reaction to the ingredients of furosemide

• low blood pressure

• signs of dehydration

• liver issues

• diabetes

• low electrolyte balance

• trouble while peeing

• gout

• Addison's disease, a rare condition affecting adrenal glands

Precautions to Take When Using Furosemide

You need to take some precautions when using furosemide to avoid side effects:

• Take Medicine as Prescribed: Don't exceed the prescribed dose to avoid the risk of potential side effects.

• Monitor Electrolyte Balance: Regularly check the levels of potassium, sodium, calcium, and magnesium to avoid fluctuations.

• Stay Hydrated: Drink water to prevent dehydration risk, but avoid taking excess fluid.

• Watch for Dizziness: As furosemide affects your alertness, stand up slowly to avoid falls and low blood pressure. Also, don't drive or perform activities that need concentration.

• Limit Sun Exposure: As this medicine can raise the chances of sun sensitivity, apply sunscreen and wear full-sleeved clothes and a hat to protect yourself from sunlight.

• Monitor Blood Sugar Levels: If you have diabetes, make sure to check your blood sugar levels.

• Avoid Alcohol: Alcohol can worsen the side effects of furosemide, which are dehydration and dizziness.

• Be Careful with Other Medicines: Avoid taking furosemide with NSAIDs and lithium to avoid negative interactions.

• Regularly Attend Kidney Checkups: If you use furosemide for a longer period, it may impact kidney functions, so always go for timely checkups.

• Avoid it Before Bedtime: Taking it before going to bed can increase the chances of frequent trips to the bathroom for peeing.

• Inform Your Gynecologist in Case of Pregnancy or Breastfeeding: As furosemide may pose health risks to mother and baby, it is unsafe during pregnancy or breastfeeding phase. 

What Things to Discuss With Your Doctor Before Using Furosemide?

Discuss these things with your doctors to help them decide whether furosemide is an appropriate medicine for you:

1. Previous and Current Health Conditions: Tell the providers if you have or had these issues:

• Heart failure

• Liver issues

• Diabetes 

• Gout

• Kidney problems

• Persistent or severe vomiting or diarrhea

• Low electrolyte balance

• Urinary retention

• Abnormal heart rhythm

• Prostate issues

• Systemic lupus erythematosus (a disease when the immune system mistakenly attacks and kills the healthy cells).

2. Sulfa Allergy

This is a type of severe reaction to sulfonamide or sulfa medications. So, individuals who are allergic to sulfa may also have allergic reactions to furosemide.

3. Other Medicines or Supplements

Furosemide may interact with over-the-counter (OTC) or prescription medicines. So, discuss with a doctor if you are also using these medications:

• Aminoglycoside antibiotics like gentamicin or neomycin

• Cephalosporin antibiotics like cefazolin, cefotiam, or cefoxitin

• Ethacrynic acid

• Cisplatin

• Lithium

• Digoxin (Lanoxin)

• Angiotensin-converting enzyme inhibitors

• Angiotensin II receptor blockers

• Antihypertensive

• Sucralfate

• Methotrexate

• Potassium Supplements

4. Pregnancy

It's unknown whether or how furosemide can impact pregnancy. So, discuss with your gynecologist if you have conceived or are planning to conceive.

5. Breastfeeding

Furosemide might impair milk production, so tell your doctor if you're breastfeeding.

Furosemide (Lasix) Dosage

The dosing will depend on the medical issues for which you're using the medicine:

For Edema (Fluid Retention)

• Adults: 20–80 mg one time a day or twice a day if needed.

• Children: 2 mg per kg a day once a day.

For High Blood Pressure

• Adults: 40 mg twice a day. A doctor may adjust the dose if required.

• Children: The doctor may determine the dose based on the body weight.
  

How to Safely Take Furosemide?

This is how you can use furosemide:

• Follow Doctor’s Instructions: Take the dose as recommended by your doctor for your specific condition.

• Have it in the Morning: Take the medicine in the morning to avoid frequent peeing at night.

• Take With or Without Food: In case of an upset stomach, have the medicine with food to prevent irritation.

• Swallow the Whole Tablet: Never chew or crush the tablet unless your doctor advises.

• Measure Oral Form Properly: Measure the oral solution accurately with the help of a measuring spoon.

• Don’t Skip a Dose: For best results, take the medicine consistently.

What to Do in an Overdose or Missed Dose Case?

• Missed Dose Case: Take the dose as soon as you remember. But, if the time is too close to take another dose, don't take the missed dose. Double dosing can cause side effects. 

• Overdose Case: If you accidentally take an excessive dose of furosemide and experience symptoms like irregular heartbeat, dizziness, and fainting, call 911 for emergency medical help or 800-222-1222 for an overdosing emergency.

Final Thoughts

The side effects of furosemide may include frequent urination, dehydration, electrolyte imbalance, low blood pressure, high blood sugar levels, and in severe cases, hearing loss, kidney failure, and gout. If you experience these symptoms, see a doctor immediately to prevent further complications. Also always use the medicine as prescribed to reduce overdose risk and discuss your preexisting health issues and other medications or supplements with your doctor before taking furosemide to avoid severe side effects.