Skip to main content

Cladribine Side Effects

Medically reviewed by Philip Thornton, DipPharm. Last updated on Nov 21, 2022.


Commonly reported side effects of cladribine include: infection, anuria, severe neutropenia, neurotoxicity, neutropenia, thrombocytopenia, acidosis, fever, increased serum creatinine, and renal insufficiency. Other side effects include: pruritus. Continue reading for a comprehensive list of adverse effects.

Applies to cladribine: oral tablet. Other dosage forms:


Oral route (Tablet)

MalignancyTreatment with cladribine may increase the risk of malignancy. Cladribine is contraindicated in patients with current malignancy. In patients with prior malignancy or with increased risk of malignancy, evaluate the benefits and risks of the use of cladribine on an individual patient basis. Follow standard cancer screening guidelines in patients treated with cladribine.Risk of TeratogenicityCladribine is contraindicated for use in pregnant women and in women and men of reproductive potential who do not plan to use effective contraception because of the potential for fetal harm. Malformations and embryolethality occurred in animals. Exclude pregnancy before the start of treatment with cladribine in females of reproductive potential. Advise females and males of reproductive potential to use effective contraception during cladribine dosing and for 6 months after the last dose in each treatment course. Stop cladribine if the patient becomes pregnant.

Serious side effects of Cladribine

Along with its needed effects, cladribine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking cladribine:

More common

  • Body aches or pain
  • chills
  • cough
  • ear congestion
  • fast heartbeat
  • fever
  • headache
  • hives, itching, skin rash
  • hoarseness
  • irritation
  • joint pain, stiffness, or swelling
  • loss of voice
  • lower back or side pain
  • painful or difficult urination
  • redness of the skin
  • runny or stuffy nose
  • sneezing
  • sore throat
  • swelling of the eyelids, face, lips, hands, or feet
  • tightness in the chest
  • troubled breathing or swallowing
  • unusual tiredness or weakness

Less common

  • Blurred vision
  • cough producing mucus
  • discouragement
  • dizziness
  • feeling sad or empty
  • lack of appetite
  • loss of interest or pleasure
  • nervousness
  • pounding in the ears
  • slow heartbeat
  • trouble concentrating
  • trouble sleeping


  • Burning or stinging of the skin
  • confusion
  • painful cold sores or blisters on the lips, nose, eyes, or genitals
  • seizures
  • stiff neck
  • vomiting

Incidence not known

  • Blistering, peeling, loosening of the skin
  • chest pain
  • diarrhea
  • muscle pain
  • red skin lesions, often with a purple center
  • red, irritated eyes
  • sores, ulcers, or white spots in the mouth or on the lips
  • swollen glands
  • unusual bleeding or bruising

Other side effects of Cladribine

Some side effects of cladribine may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Back pain
  • difficulty in moving
  • muscle stiffness
  • trouble sleeping

Less common

  • Thinning or loss of hair

For Healthcare Professionals

Applies to cladribine: intravenous solution, oral tablet.


Very common (10% or more): Neutropenia, thrombocytopenia, anemia, purpura

Common (1% to 10%): Febrile neutropenia

Uncommon (0.1% to 1%): Bone marrow suppression with prolonged pancytopenia, aplastic anemia, hypereosinophilia, myelodysplastic syndrome

Postmarketing reports: Hemolytic anemia, febrile neutropenia[Ref]


Common (1% to 10%): Renal impairment, renal failure


Very common (10% or more): Nausea (28%), anorexia (17%), vomiting (13%), diarrhea (10%)

Common (1% to 10%): Constipation, abdominal pain, flatulence

Uncommon (0.1% to 1%): Mucositis[Ref]


Very common (10% or more): Rash (28%), diaphoresis, pruritus

Common (1% to 10%): Hyperhidrosis, petechiae, ecchymosis, urticaria

Uncommon (0.1% to 1%): Stevens-Johnson syndrome, toxic skin eruption, toxic epidermal necrolysis

Rare (less than 0.1%): Alopecia[Ref]

Nervous system

Very common (10% or more): Headache

Common (1% to 10%): Dizziness, somnolence

Uncommon (0.1% to 1%): Depressed level of consciousness, neurological toxicity (including peripheral sensory neuropathy, motor neuropathy (paralysis), polyneuropathy, paraparesis)[Ref]


Very common (10% or more): Administration site reaction[Ref]


Common (1% to 10%): Weight loss

Uncommon (0.1% to 1%): Tumor lysis syndrome, metabolic acidosis[Ref]


Common (1% to 10%): Edema, tachycardia, myocardial ischemia, peripheral edema

Rare (less than 0.1%): Heart failure, arrhythmia, heart murmur, hypotension, thrombosis[Ref]


Common (1% to 10%): Arthralgia, myalgia

Uncommon (0.1% to 1%): Muscular weakness, paraparesis[Ref]


Very common (10% or more): Cough

Common (1% to 10%): Pulmonary interstitial infiltrates (including lung infiltration, interstitial lung disease, pneumonitis and pulmonary fibrosis), abnormal breath sounds, abnormal chest sounds, dyspnea, rales[Ref]


Common (1% to 10%): Hypersensitivity[Ref]


Uncommon (0.1% to 1%): Increases in bilirubin, increases in transaminases, jaundice[Ref]


Very common (10% or more): Infection (unspecified) (up to 28%)

Common (1% to 10%): Bacteremia, cellulitis, localized infection, pneumonia, septic shock, serious infection, opportunistic infection[Ref]


Postmarketing reports: Conjunctivitis[Ref]


Very common (10% or more): Fatigue, pyrexia, pain

Common (1% to 10%): Asthenia, chills, malaise, localized edema, chills[Ref]


Postmarketing reports: Secondary malignancies[Ref]


Common (1% to 10%): Confusion, anxiety, insomnia[Ref]

Frequently asked questions


1. Product Information. Leustatin (cladribine). Ortho Biotech Inc. 2001.

2. Cerner Multum, Inc. UK Summary of Product Characteristics.

3. Pharmaceutical Society of Australia. APPGuide online. Australian prescription products guide online. 2006.

Further information

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

Some side effects may not be reported. You may report them to the FDA.