Furosemide – a water tablet for removing excess water

Furosemide – a water tablet for removing excess water

Furosemide is a water tablet (diuretic) for fluid overload.

What is Furosemide?

Furosemide is a type of medicine called a loop diuretic. It is commonly known as a “water tablet” because it helps the body get rid of excess fluid.

It is much more potent than some other diuretics (like bumetanide); roughly 40 mg of furosemide is equivalent to 1 mg of bumetandie.

How it works

• Furosemide works in the kidneys, specifically in a part called the Loop of Henle.

• It blocks the reabsorption of salt (sodium) and chloride into the body.

• Because water follows salt, the excess fluid is drawn out of the bloodstream and tissues and passed out of the body as urine.

• This reduces the amount of fluid circulating in the vessels and relieves pressure on the heart.

Uses

Common uses

Furosemide is used to treat oedema (fluid retention/swelling) associated with:

• Heart failure: Where the heart isn’t pumping efficiently, leading to fluid in the lungs or ankles.

• Chronic kidney disease (CKD) and Nephrotic Syndrome: To help the kidneys manage fluid balance.

• Liver disease (cirrhosis): To reduce fluid build-up in the abdomen or legs.

Less common uses

• Resistant high blood pressure: Sometimes used when other blood pressure medications haven’t worked well enough.

• High calcium levels (hypercalcaemia): It can aslo be used to stop kidneys from absorbing too much calcium, allowing the extra amount to safely leave your body when you go to the toilet.

Dosage

• Usually taken once daily in the morning.

• Taking it in the morning prevents sleep disruption caused by needing to use the bathroom during the night.

• Typical doses range is 40 mg – 80 mg daily, though higher doses may be used in severe cases. This dose range is equivalent to 1 – 2 mg of furosemide.

• In some situations, it may be taken twice a day (morning and midday).

Side-effects

Common side-effects

• Increased urination: This is the intended effect but can be frequent.

• Dizziness or lightheadedness: Especially when standing up quickly (due to lower blood pressure).

• Dehydration: Feeling very thirsty or having dark-coloured urine.

• Muscle cramps: Often caused by changes in salt/mineral levels.

Less common (but more serious) side-effects

• Electrolyte imbalance: Significant decreasd in potassium, sodium, or magnesium levels.

• Gout: It can cause a build-up of uric acid, leading to painful joint swelling.

• Hearing changes: Very high doses can rarely cause ringing in the ears (tinnitus) or hearing loss.

• Skin rash: Severe allergic reactions are rare but require immediate medical attention.

Monitoring

Doctors should monitor:

• Blood tests: To check kidney function (creatinine/GFR) and levels of salts like potassium, sodium, and magnesium.

• Weight: Monitoring daily weight is a good way to see if the “water weight” is decreasing.

• Blood pressure: To ensure it doesn’t drop too low (hypotension).

Note: Because furosemide increases urine output, you will likely need to plan your day around being near a bathroom for a few hours after taking your dose.