Skip to main content

Leustatin (injection)

Generic name: cladribine (injection) [ KLAD-ri-been ]
Drug class: Antimetabolites

Medically reviewed by on Feb 16, 2023. Written by Cerner Multum.

What is Leustatin?

Leustatin is a cancer medicine that is used to treat hairy cell leukemia (a type of blood cancer).

Leustatin may also be used for purposes not listed in this medication guide.


Leustatin can increase your risk of bleeding or infection. Call your doctor if you have unusual bruising or bleeding, or new signs of infection (fever, chills, cough, chest pain, mouth sores, skin sores, sore throat, trouble breathing).

Very high doses of cladribine injection can cause nerve damage or paralysis that may not be reversible. However, this effect is rare when Leustatin is given in recommended doses.

Before taking this medicine

You should not use Leustatin if you are allergic to it.

Tell your doctor if you have ever had:

  • heart problems;

  • liver or kidney disease; or

  • weak immune system (caused by disease or by using certain medicine).

Leustatin may harm an unborn baby. Use effective birth control to prevent pregnancy, and tell your doctor if you become pregnant.

You should not breastfeed while using Leustatin.

How is Leustatin given?

Leustatin is given as an infusion into a vein. A healthcare provider will give you this injection.

Leustatin is usually given around the clock for 7 days in a row. Your doctor will determine how many 7- day treatments you will receive and how often.

Leustatin can increase your risk of bleeding or infection. You will need frequent medical tests, and your next dose may be delayed based on the results.

If Leustatin accidentally gets on your skin, wash it thoroughly with soap and warm water.

What happens if I miss a dose?

Since this medication is given in a healthcare setting around the clock, you will not miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Very high doses of Leustatin can cause nerve damage. In some people, this has resulted in loss of movement (paralysis) that may not be reversible. However, such severe symptoms are rare when Leustatin is given in recommended doses. Talk with your doctor if you have concerns about this risk.

What should I avoid while receiving cladribine?

Do not receive a "live" vaccine while using Leustatin, or you could develop a serious infection. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Leustatin side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Leustatin may cause serious side effects. Call your doctor at once if you have:

  • numbness, tingling, weakness, or burning pain in your fingers or toes;

  • loss of movement in any part of your body;

  • redness, swelling, or itching under your skin;

  • low blood cell counts--fever, chills, tiredness, mouth sores, skin sores, easy bruising, unusual bleeding, pale skin, cold hands and feet, feeling light-headed or short of breath;

  • kidney problems--little or no urination, swelling in your feet or ankles, feeling tired or short of breath;

  • signs of infection--fever, chills, cough, chest pain, mouth sores, skin sores, sore throat, trouble breathing; or

  • signs of tumor cell breakdown--tiredness, weakness, muscle cramps, nausea, vomiting, diarrhea, fast or slow heart rate, tingling in your hands and feet or around your mouth.

Common side effects of Leustatin may include:

  • fever;

  • nausea, vomiting, diarrhea;

  • headache, tiredness;

  • rash;

  • cough; or

  • pain, bruising, swelling, or irritation where the medicine was injected.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect Leustatin?

Leustatin can harm your kidneys, especially if you also use certain medicines for infections, cancer, osteoporosis, organ transplant rejection, bowel disorders, high blood pressure, or pain or arthritis (including Advil, Motrin, and Aleve).

Other drugs may affect Leustatin, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Popular FAQ

Over 96 weeks, 81% of patients who took Mavenclad were relapse-free compared to 63% of those who took a placebo. Mavenclad also decreased 3-month progression of disability due to MS when compared to a placebo. Continue reading

No, Mavenclad is not a chemotherapy (cancer) drug. It is an oral purine antimetabolite approved for the treatment of relapsing forms of multiple sclerosis (MS), to include relapsing-remitting disease and active secondary progressive disease, in adults. Mavenclad tablets are taken by mouth and are given as two yearly treatment courses. Continue reading

Weight gain has not been reported as a side effect with Mavenclad (generic name: cladribine), an oral medicine used for multiple sclerosis (MS). The most common side effects reported with Mavenclad include upper respiratory tract infections, headache and a decrease in white blood cells. Continue reading

Hair loss (alopecia) is an infrequent side effect with Mavenclad. In clinical studies, hair loss occurred in 3% (3 out of every 100) of patients treated with Mavanclad (generic name: cladribine) compared to 1% of patients receiving a placebo (inactive) treatment. Continue reading

More FAQ

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.