In the U.S.—

In Canada—

Other commonly used names are 2-chlorodeoxyadenosine; 2-CdA.

• Antineoplastic

Cladribine ( KLAD-ri-been) belongs to the group of medicines called antimetabolites. It is used to treat hairy cell leukemia, a cancer of the blood and bone marrow. It is also sometimes used to treat other kinds of cancer, as determined by your doctor.

Cladribine interferes with the growth of cancer cells, which are eventually destroyed. Since the growth of normal body cells may also be affected by cladribine, other effects will also occur. Some of these may be serious and must be reported to your doctor. Other effects may not be serious but may cause concern. Some effects may not occur for months or years after the medicine is used.

Before you begin treatment with cladribine, you and your doctor should talk about the good this medicine will do as well as the risks of using it.

Cladribine is to be administered only by or under the immediate supervision of your doctor. It is available in the following dosage form:

Parenteral
• Injection (U.S. and Canada)

In deciding to use a medicine, the risks of taking the medicine must be weighed against the good it will do. This is a decision you and your doctor will make. For cladribine, the following should be considered:

Allergies—Tell your doctor if you have ever had any unusual or allergic reaction to cladribine.

Pregnancy—There is a chance that this medicine may cause birth defects if either the male or female is taking it at the time of conception or if it is taken during pregnancy. Cladribine has been shown to cause birth defects in mice and rabbits. In addition, many cancer medicines may cause sterility which could be permanent. Although sterility has not been reported with this medicine, fertility problems do occur in male monkeys and the possibility should be kept in mind.

Be sure that you have discussed this with your doctor before receiving this medicine. It is best to use some kind of birth control while you are receiving cladribine. Tell your doctor right away if you think you have become pregnant while receiving cladribine.

Breast-feeding—It is not known whether cladribine passes into breast milk. However, because this medicine may cause serious side effects, breast-feeding is generally not recommended while you are receiving it.

Children—There is no specific information comparing use of cladribine in children with use in other age groups. However, cladribine has been reported to be tested in children with certain types of cancers of the blood.

Older adults—Many medicines have not been studied specifically in older people. Therefore, it may not be known whether they work exactly the same way they do in younger adults. Although there is no specific information comparing use of cladribine in the elderly with use in other age groups, it is not expected to cause different side effects or problems in older people than it does in younger adults.

Other medicines—Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. When you are receiving cladribine it is especially important that your health care professional know if you are taking any of the following:

• Amphotericin B by injection (e.g., Fungizone) or
• Antithyroid agents (medicine for overactive thyroid) or
• Azathioprine (e.g., Imuran) or
• Chloramphenicol (e.g., Chloromycetin) or
• Colchicine or
• Flucytosine (e.g., Ancobon) or
• Ganciclovir (e.g., Cytovene) or
• Interferon (e.g., Intron A, Roferon-A) or
• Plicamycin (e.g., Mithracin) or
• Zidovudine (e.g., AZT, Retrovir) or
• If you have ever been treated with radiation or cancer medicines—Cladribine may increase the effects of these medicines or radiation therapy on the blood

• Probenecid (e.g., Benemid) or
• Sulfinpyrazone (e.g., Anturane)—Cladribine may raise the amount of uric acid in the blood. Since these medicines are used to lower uric acid levels, they may not be as effective in patients receiving cladribine

• Chickenpox (including recent exposure) or
• Herpes zoster (shingles)—Risk of severe disease affecting other parts of the body

• Gout (history of) or
• Kidney stones (history of)—Cladribine may increase levels of uric acid in the body, which can cause gout or kidney stones

• Infection—Cladribine may decrease your body's ability to fight infection

This medicine may cause mild nausea and may also cause vomiting. However, it is very important that you continue to receive the medicine even if you begin to feel ill. Ask your health care professional for ways to lessen these effects.

Dosing—

The dose of cladribine will be different for different patients. The dose that is used may depend on a number of things, including what the medicine is being used for, the patient's weight, and whether or not other medicines are also being taken. If you are receiving cladribine at home, follow your doctor's orders or the directions on the label. If you have any questions about the proper dose of cladribine, ask your doctor.

It is very important that your doctor check your progress at regular visits to make sure that this medicine is working properly and to check for unwanted effects.

While you are being treated with cladribine, and after you stop treatment with it, do not have any immunizations (vaccinations) without your doctor's approval. Cladribine may lower your body's resistance and there is a chance you might get the infection the immunization is meant to prevent. In addition, other persons living in your household should not take oral polio vaccine since there is a chance they could pass the polio virus on to you. Also, avoid persons who have taken oral polio vaccine within the last several months. Do not get close to them and do not stay in the same room with them for very long. If you cannot take these precautions, you should consider wearing a protective face mask that covers the nose and mouth.

Cladribine can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

• If you can, avoid people with infections, colds, or flu. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
• Check with your doctor immediately if you notice any unusual bleeding or bruising; black, tarry stools; blood in urine or stools; or pinpoint red spots on your skin.
• Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
• Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
• Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
• Avoid contact sports or other situations where bruising or injury could occur.

Along with its needed effects, a medicine may cause some unwanted effects. Some side effects will have signs or symptoms that you can see or feel. Your doctor may watch for others by doing certain tests.

Also, because of the way cancer medicines act on the body, there is a chance that they might cause other unwanted effects that may not occur until months or years after the medicine is used. These delayed effects may include certain types of cancer. Discuss these possible effects with your doctor.

Check with your doctor or nurse immediately if any of the following side effects occur:

• More common
  • Black, tarry stools;  blood in urine ;  cough or hoarseness, accompanied by fever or chills ;  fever;  lower back or side pain, accompanied by fever or chills;  painful or difficult urination, accompanied by fever or chills;  pinpoint red spots on skin;  unusual bleeding or bruising  
  
  

Check with your health care professional as soon as possible if any of the following side effects occur:

• More common
  • Skin rash 
  
  

• Less common
  • Pain or redness at place of injection;  shortness of breath;  stomach pain;  swelling of feet or lower legs;  unusually fast heartbeat  
  
  

This medicine may also cause the following side effects that your doctor will watch out for:

• More common
  • Anemia;  low white cell counts in blood  
  
  

Other side effects 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
  • Headache;  loss of appetite;  nausea;  unusual tiredness;  vomiting 
  
  

• Less common
  • Constipation;  diarrhea;  dizziness;  general feeling of discomfort or illness;  itching;  muscle or joint pain;  sweating;  trouble in sleeping;  weakness 
  
  

Other side effects not listed above may also occur in some patients. If you notice any other effects, check with your doctor.

Once a medicine has been approved for marketing for a certain use, experience may show that it is also useful for other medical problems. Although these uses are not included in product labeling, cladribine is used in certain patients with the following conditions:

• Cancer of the blood and lymph system
• Waldenström's macroglobulinemia (a certain type of cancer of the blood)

Other than the above information, there is no additional information relating to proper use, precautions, or side effects for these uses.