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Treatment and the treatment process

Diuretics

Diuretics are medicines that help the kidneys remove extra water and salt. In leukemia treatment they are used mainly when there is too much fluid in the body.

Last updated: ~2 min read
On a dark navy background, a glowing teal kidney tubule with small golden gates opening and streams of water flowing out.
Figure 1.Diuretics help the kidneys remove extra water.

01Short answer

Leukemia treatment involves a lot of IV fluid, blood products and medicines. Sometimes the body cannot remove this fluid fast enough: weight goes up, the legs and face swell, and fluid can collect in the lungs and cause breathlessness. The doctor may then prescribe a diuretic ("water tablet") — most often a loop diuretic such as furosemide. Diuretics may also be used to keep urine flowing during intensive hydration or to manage fluid balance in heart failure. They increase the loss of potassium, magnesium and sodium and can strain the kidneys, so blood tests, weight and urine are checked regularly. Only the doctor chooses the medicine, dose and duration.

02Simple explanation

Extra fluid. Sometimes the body can’t clear the fluid it is given.

Help. Diuretics help the kidneys make more urine.

The cost. Salts are lost along with water.

Checks. Blood tests and weight protect the balance.

03Scientific explanation

Loop diuretics (furosemide, bumetanide, torasemide) block the Na-K-2Cl transporter in the thick ascending limb of the loop of Henle, causing a strong, fast diuresis. Thiazides act in the distal tubule and potassium-sparing diuretics (spironolactone, amiloride) in the collecting duct.

In leukemia: fluid overload, pulmonary oedema, heart failure and sometimes transfusion-related volume overload. When tumour lysis risk is high, diuretics are considered only after volume has been restored and with caution; in dehydration they are harmful.

Side effects: hypokalaemia, hypomagnesaemia, hyponatraemia, dehydration, worsening kidney function and low blood pressure; at high doses, ototoxicity, especially with aminoglycosides. Potassium loss raises arrhythmia risk with QT-prolonging medicines.

04What happens in the body?

How do diuretics work?

In the kidney tubules, sodium and water are normally taken back into the blood. Diuretics close certain "gates" in this process, so more water leaves as urine.

Swelling goes down

Fluid in the tissues moves back into the blood and the kidneys remove it. Swelling of the legs and face gradually eases.

A soft abstract silhouette of a lower leg and ankle, its swollen outline returning to normal in teal light.
Figure 2.Swelling in the tissues gradually eases.

Breathing gets easier

When fluid collects in the lungs, breathing is hard. A diuretic can reduce this fluid and ease breathing, but the doctor always looks for the cause.

Stylised lungs on a dark background, a grey mist at their base dissolving into teal and gold light.
Figure 3.With less fluid in the lungs, breathing is easier.

05How diuretic treatment works

A simplified outline.

Assessment — Weight, swelling, breathing.1AssessmentWeight, swelling, breathing.
Prescription — Tablet or IV.2PrescriptionTablet or IV.
Monitoring — Weight and urine.3MonitoringWeight and urine.
Blood tests — Potassium and kidneys.4Blood testsPotassium and kidneys.
Less fluidSwelling and breathlessness ease.
Balance keptSalts replaced when needed.
Short or long termDepends on the situation.

06Main groups of diuretics

GroupExamplesNote
Loop diureticsFurosemide, bumetanide, torasemideStrong and fast; potassium loss
ThiazidesHydrochlorothiazide, indapamideMilder; also used for blood pressure
Potassium-sparingSpironolactone, amiloridePotassium may rise
OsmoticMannitolSpecial situations

* Only your treating doctor chooses the type, dose and duration of a diuretic.

07Key terms

Diuretic
A medicine that increases urine output.
Diuresis
Passing urine.
Oedema
Fluid collecting in the tissues.
Pulmonary oedema
Fluid collecting in the lungs.
Hypokalaemia
Low potassium in the blood.
Fluid overload
Too much fluid in the body.

08Key points

  • Diuretics help remove extra fluid.
  • They remove salts along with water.
  • Blood tests are checked often during treatment.
  • In dehydration, diuretics can do harm.
  • Never start or stop a diuretic on your own.
  • Report dizziness and cramps.

09Frequently asked questions

Do diuretics harm the kidneys?

Used correctly, usually not, but with dehydration kidney function can worsen — that is why blood tests are checked.

Why am I given potassium after a diuretic?

Diuretics can cause potassium loss; the team replaces it according to your results.

Can I take my diuretic in the evening?

Your doctor decides the timing; it is often given in the morning so you don’t have to get up at night.

Do I need to continue at home?

It depends on the reason; your team will give a clear plan when you leave.

10Questions for your doctor

Take these questions to your appointment. The ones you save are collected on the “My questions” page and stay on this device only.

  1. Do diuretics harm the kidneys?

  2. Why am I given potassium after a diuretic?

  3. Can I take my diuretic in the evening?

  4. Do I need to continue at home?

My questions

12Sources

  1. MedlinePlus. Furosemide
  2. MedlinePlus. Fluid and Electrolyte Balance
  3. MedlinePlus. Potassium test
  4. MedlinePlus. Creatinine blood test
  5. American Cancer Society. Infections in People with Cancer
  6. National Cancer Institute (NCI). Monoclonal Antibodies
  7. MedlinePlus (U.S. National Library of Medicine). Comprehensive Metabolic Panel (CMP)
  8. MedlinePlus (U.S. National Library of Medicine). Liver Function Tests
  9. MedlinePlus (U.S. National Library of Medicine). Electrolyte Panel
  10. National Cancer Institute (NCI). Drugs Approved for Leukemia
Medical disclaimerThis information is for educational purposes only and does not replace medical advice.
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