Pentostatin, is a chemotherapy drug that is given as a treatment for some types of leukaemia. It is most commonly used to treat a type of leukaemia called hairy cell leukaemia. It may be used as part of research trials to treat other types of cancer such as cutaneous T-cell lymphoma. This information describes pentostatin, how it is given and some of its possible side effects. It should ideally be read with our general information about chemotherapy and about your type of leukaemia or lymphoma.

If you have any further questions you can ask your doctor or nurse at the hospital where you are having your treatment, or speak to one of our cancer support service nurses.

Pentostatin is a clear, colourless fluid.

Pentostatin may given by injection:

• into a vein (intravenously) through a fine tube (cannula) placed into the vein
• through a fine plastic tube which is inserted under the skin into a vein near the collarbone (central line) or passed through a vein in the crook of the arm (PICC line).

While having pentostatin you will also be given a drip (infusion) of fluid to help keep your kidneys working normally.

Chemotherapy is usually given as a course of several sessions (or cycles) of treatment over a few months. The length of your treatment and the number of cycles you have will depend on the type of cancer for which you are being treated. Your nurse or doctor will discuss your treatment plan with you.

Each person’s reaction to chemotherapy is different. Some people have very few side effects, while others may experience more. The side effects described in this information will not affect everyone who is given pentostatin.

We have outlined the most common side effects as well as rarer ones, so that you can be aware of them if they occur. However, we have not included those which are very rare and therefore extremely unlikely to affect you.
If you notice any effects that you think may be due to the drug, but that are not listed in this information, please discuss these with your doctor or chemotherapy nurse.

Lowered resistance to infection Pentostatin can reduce the production of white blood cells by the bone marrow, making you more prone to infection. This effect can begin seven days after treatment has been given. Your blood cells will then increase steadily, and will usually have returned to normal levels before your next cycle of chemotherapy is due.

Contact your doctor or the hospital straightaway if:

• your temperature goes above 38ºC (100.5ºF)
• you suddenly feel unwell (even with a normal temperature).

You will have a blood test before having more chemotherapy to make sure that your cells have recovered. Occasionally it may be necessary to delay your treatment if the number of blood cells (the blood count) is still low.

Bruising or bleeding Pentostatin can reduce the production of platelets (which help the blood to clot). Let your doctor know if you have any unexplained bruising or bleeding, such as nosebleeds, blood spots or rashes on the skin, or bleeding gums.

Anaemia (low number of red blood cells) While having treatment with pentostatin you may become anaemic. This may make you feel tired and breathless. Let your doctor or nurse know if these symptoms are a problem.

Feeling sick (nausea) and being sick (vomiting) If you do feel sick this may begin a few hours after the treatment is given and last for up to a day. Your doctor can prescribe very effective anti-sickness (anti-emetic) drugs to prevent, or greatly reduce, nausea and vomiting. If the sickness is not controlled, or continues, tell your doctor; they can prescribe other anti-sickness drugs which may be more effective. Some anti-sickness drugs can cause constipation. Let your doctor or nurse know if this is a problem.

Skin changes Your skin may feel dry and may itch. Some people notice spots (like acne) on their face or upper body. This usually returns to normal a few months after the treatment has finished. Using a gentle or unperfumed moisturiser on dry areas can help. A skin rash may occur when you first start the treatment, but may not happen again as your treatment continues.

Lethargy (feeling weak) and fatigue (extreme tiredness) You may suffer from fatigue. It is important to allow yourself plenty of time to rest.

Loss of appetite A dietitian or specialist nurse at your hospital can give advice on boosting your appetite, coping with eating difficulties and maintaining weight.

Gritty eyes can occur due to inflammation of the lining (conjunctiva) of the eyelids. If this happens it is important to tell your doctor, who can prescribe soothing eye drops.

Diarrhoea This can usually be controlled with anti-diarrhoea medicines but let your doctor know if it is severe or if it continues. It is important to drink plenty of fluids if you do have diarrhoea.

Mouth sores and ulcers Your mouth may become sore, or you may notice small ulcers during this treatment. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush, can help reduce the risk of this happening. Tell your nurse or doctor if you have any of these problems, as they can give you special mouthwashes and medicine to prevent or clear any mouth infection.

Allergic reaction An allergic reaction may occur while you are having the drip or shortly afterwards. Signs of an allergic reaction include skin rashes and itching, high temperature, shivering, reddening of the face, dizziness, headache, breathlessness, anxiety and a feeling that you want to pass urine. You will be monitored for any signs of an allergic reaction while your treatment is being given. Tell your doctor or nurse if you have any of these..

Fever and chills These may occur with pentostatin but they do not usually last long. Your doctor may prescribe medicines to reduce these effects.

Your liver may be temporarily affected Pentostatin may cause changes in the way that your liver works, though your liver will return to normal when the treatment is finished. This is very unlikely to cause you any harm, but your doctor will monitor this carefully. Samples of your blood will be taken from time to time to monitor your liver and check that it is working properly.

Your kidneys may be affected Usually this does not cause any symptoms, and the effect is usually mild, but if the effect is severe the kidneys can be permanently damaged unless treatment is stopped. For this reason your kidneys will be checked by a blood test before each treatment. If necessary, you may be given medicine to help you to pass urine.

If you are asked to drink extra fluid it is important to do this, or to let your doctor know if you find this difficult, perhaps because you are feeling sick.

Changes to the lungs Higher doses of pentostatin may cause some changes to lung tissue. Tell your doctor if you notice any coughing or breathlessness.

Changes in the way your heart works Higher doses of pentostatin may cause changes in the muscle of the heart. This can affect how the heart works. The effect on the heart depends on the dose given. It is very unusual for the heart to be affected if you receive standard doses. Tests to see how well your heart is working may sometimes be carried out before the drug is given.

Hair loss Hair loss is rare, but your hair may thin, or occasionally fall out completely. If this occurs it usually begins about 3–4 weeks after starting treatment, although it may occur earlier. It is temporary and your hair will regrow once the treatment is finished.

Leakage into the tissue If pentostatin leaks into the tissue around the vein it can damage the tissue in that area. If you notice any stinging or burning around the vein while the drug is being given, or any leakage of fluid from the cannula site, it is very important that you tell the doctor or nurse.

If the area around the injection site becomes red or swollen at any time you should either notify the doctor or nurse on the ward, or if at home, ring the clinic or ward and ask to speak to the doctor or nurse.

Risk of blood clots Cancer can increase your risk of developing a blood clot (thrombosis), and having chemotherapy may increase this risk further. A blood clot may cause symptoms such as pain, redness and swelling in a leg, or breathlessness and chest pain. Blood clots can be very serious so it is important to tell your doctor straightaway if you have any of these symptoms. However, most clots can usually be successfully treated with drugs to thin the blood. Your doctor or nurse can give you more information.

Other medicines Some other medicines can be harmful when you are having chemotherapy. Tell your doctor about any medications you are taking, including non-prescribed drugs such as complementary therapies and herbal drugs.

Fertility Your ability to become pregnant or father a child may be affected by taking this drug. It is important to discuss fertility with your doctor before starting treatment.

Contraception It is not advisable to become pregnant or father a child while taking pentostatin, as the developing foetus may be harmed. It is important to use effective contraception while taking this drug, and for at least a few months afterwards. Again, discuss this with your doctor.

This section is based on our Pentostatin factsheet which has been compiled using information from a number of reliable sources, including:

• British National Formulary (54th edition). British Medical Association and Royal Pharmaceutical Society of Great Britain, September 2007.
• British Committee for Standards in Haematology website: www.bcshguidelines.com (Nov 2007).
• The Medicines.org.uk website – www.medicines.org.uk (November 2007).
• Essential Haematology (5th edition). AV Hoffbrand et al. Blackwell Scientific Publications, 2006.
• Wintrobe’s Clinical Haematology (11th edition). RG Lee et al. Lippincott Williams and Wilkins, 2003.

For further references, please see the general bibliography.