Cladribine is used to treat adults with relapsing forms of multiple sclerosis (MS; a disease in which the nerves do not function properly and people may experience weakness, numbness, loss of muscle coordination, and problems with vision, speech, and bladder control), including relapsing-remitting forms (course of disease where symptoms flare up from time to time) and active secondary progressive forms (course of disease that follows a relapsing-remitting course where symptoms gradually become worse over time). Cladribine is generally used in patients who have already tried another treatment for MS. Cladribine in a class of medications called purine antimetabolites. It works by stopping certain cells of the immune system from causing nerve damage.

Side Effects Of Cladribine

Cladribine may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

  • headache
  • nausea
  • back pain
  • joint pain and stiffness
  • difficulty falling asleep or staying asleep
  • depression
  • hair loss
  • tingling, itching, or burning sores on gums, lips, or mouth

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

  • fever, sore throat, chills, aching or painful muscles, cough, or other signs of infection
  • cough, chest pain, coughing up blood or mucus, weakness or tiredness, weight loss, loss of appetite, chills, fever, night sweats
  • a painful rash with blisters
  • burning, tingling, numbness, or itchiness of the skin
  • rash, difficulty breathing or swallowing, swelling or itching of the face, lips, tongue, or throat
  • chills, fever, nausea, vomiting, pain in your back, side, or groin, frequent and painful urination
  • unusual bleeding or bruising
  • weakness on one side of your body, loss of coordination in your arms or legs, decreased strength, problems with balance, confusion, changes in your vision, thinking, memory, or personality
  • shortness of breath, fast heartbeat, headache, dizziness, pale skin, confusion, tiredness
  • nausea, vomiting, extreme tiredness, loss of appetite, pain in the upper right part of the stomach, yellowing of the skin or eyes, dark urine
  • shortness of breath, fast or irregular heartbeat, swelling in a part of your body

Cladribine may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

Warnings & Precautions

Before taking cladribine:

  • tell your doctor and pharmacist if you are allergic to cladribine, any other medications, or any of the ingredients in cladribine tablets. Ask your pharmacist or check the Medication Guide for a list of the ingredients.
  • tell your doctor and pharmacist what other prescription and nonprescription medications, vitamins, and nutritional supplements you are taking or plan to take. Be sure to mention any of the following: cilostazol; dipyridamole (Persantine, in Aggrenox); elrombopag (Promacta); furosemide (Lasix); gabapentin (Gralise, Horizant, Neurontin); ibuprofen (Advil, Midol, Motrin, others); interferon beta (Avonex, Betaseron, Extavia, Rebif); lamivudine (Epivir, in Epzicom); medications that suppress the immune system such as azathioprine (Azasan), cyclosporine (Gengraf, Neoral, Sandimmune), methotrexate (Otrexup, Rasuvo, Trexall, Xatmep), sirolimus (Rapamune), and tacrolimus (Astagraf, Envarsus, Prograf); nifedipine (Adalat, Procardia); nimodipine (Nymalize); reserpine; ribavirin (Rebetol, Ribasphere, Virazole); rifampin (Rifadin, Rimactane, in Rifamate, in Rifater); ritonavir (Norvir, in Kaletra, in Technivie, in Viekira); stavudine (Zerit); steroids such as dexamethasone (Decadron, Dexpak), methylprednisolone (Medrol), and prednisone (Rayos); sulindac; and zidovudine (Retrovir, in Combivir, in Trizivir). Your doctor may need to change the doses of your medications or monitor you carefully for side effects. Many other medications may also interact with cladribine, so be sure to tell your doctor about all the medications you are taking, even those that do not appear on this list.
  • if you are taking any other medications by mouth, take them 3 hours before or 3 hours after cladribine.
  • tell your doctor what herbal products you are taking, especially curcumin and St. John’s wort.
  • tell your doctor if you have human immunodeficiency virus (HIV), hepatitis (a virus that infects the liver and may cause severe liver damage), tuberculosis (TB; a serious infection that affects the lungs and sometimes other parts of the body), or other ongoing infections. Your doctor will probably tell you not to take cladribine.
  • tell your doctor if you have or have ever had liver, kidney, or heart disease.
  • tell your doctor if you are breast-feeding. You should not breast-feed during a treatment cycle, and for 10 days after the last dose of the treatment cycle.
  • if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking cladribine.
  • do not have any vaccinations within 4 to 6 weeks before, during, or after your treatment with cladribine without talking to your doctor. Talk to your doctor about whether you should receive any vaccinations before you begin your treatment.

Dosage Of Cladribine

Cladribine comes as a tablet to take by mouth with water. It is usually taken with or without food, once a day for 4 or 5 days in a row for one treatment cycle. A second treatment cycle should be repeated 23 to 27 days later to complete one treatment course. A second course (2 treatment cycles) is usually given at least 43 weeks after the last dose of the second cycle. Take cladribine at around the same time every day. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take cladribine exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Swallow the tablets whole; do not split, chew, or crush them.

Remove the tablet from the blister pack with dry hands and then swallow the tablet right away. Limit the time that the tablet is in contact with your skin. Avoid touching your nose, eyes, and other parts of your body. After you take the medication, wash your hands well with water. If the tablet comes in contact with any surfaces or other parts of your body, also wash them well with water right away.


Keep all appointments with your doctor and the laboratory. Your doctor will order certain tests before, during, and after your treatment to make sure it is safe for you to take cladribine and to check your body’s response to cladribine.

Do not let anyone else take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.