Pentostatin (Nipent)

Pentostatin is a type of chemotherapy. It is also called Nipent. You pronounce pentostatin as pen-toh-sta-tin.

It is treatment for hairy cell leukaemia and T-cell prolymphocytic leukaemia.

How does pentostatin work?

Pentostatin is one of a group of chemotherapy drugs known as antimetabolites Open a glossary item. These drugs stop cells making and repairing DNA. DNA is the genetic material of a cell. Cancer cells need to make and repair DNA so they can grow and multiply.

How do you have pentostatin?

You have pentostatin into your bloodstream (intravenously). You might have it as a slow injection over a few minutes or as a drip.

Into your bloodstream

You might have treatment through a long plastic tube that goes into a large vein in your chest. The tube stays in place throughout the course of treatment. This can be a:

  • central line
  • PICC line
  • portacath

If you don't have a central line

You might have treatment through a thin short tube (a cannula) that goes into a vein in your arm. You have a new cannula each time you have treatment.

How often do you have pentostatin?

You have pentostatin as cycles of treatment. This means that you have the drug and then a rest to allow your body to recover. Each cycle of treatment takes 28 days (4 weeks).

You are likely to have pentostatin every 2 weeks. It takes up to 30 minutes to have. You usually have fluids into the bloodstream before and after the drug.

You usually continue treatment until the leukaemia is under control as long as the side effects are not too bad.


You have blood tests before and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

What are the side effects of pentostatin?

Side effects can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, pharmacist or nurse will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

  • you have severe side effects

  • your side effects aren’t getting any better

  • your side effects are getting worse

  • the side effects are affecting your daily life

Early treatment can help manage side effects better. 

Contact your advice line, doctor or nurse immediately if you have signs of infection, such as a temperature above 37.5C or below 36C, or if you develop a severe skin reaction. Signs of a severe skin reaction include peeling or blistering of the skin.

We haven't listed all the side effects here. Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Allergic reaction

A reaction may happen during the infusion. Symptoms can include a skin rash, itching, swelling of the lips, face or throat, breathing difficulties, fever and chills.

Tell your doctor or nurse immediately if at any time you feel unwell. They will slow or stop your drip for a while and give you medicine to help relieve your symptoms.

Increased risk of infection

Increased risk of getting an infection is due to a drop in white blood cells. Symptoms include a change in temperature, aching muscles, headaches, feeling cold and shivery and generally unwell. You might have other symptoms depending on where the infection is.

Infections can sometimes be life threatening. You should contact your advice line urgently if you think you have an infection. 

Breathlessness and looking pale

You might be breathless and look pale due to a drop in red blood cells. This is called anaemia.

Bruising, bleeding gums or nosebleeds

This is due to a drop in the number of platelets in your blood. These blood cells help the blood to clot when we cut ourselves. You may have nosebleeds or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechiae).

Tiredness and weakness (fatigue)

Tiredness and weakness (fatigue) can happen during and after treatment. Doing gentle exercises each day can keep your energy up. Don't push yourself, rest when you start to feel tired and ask others for help.

Feeling or being sick

Feeling or being sick is usually well controlled with anti sickness medicines. It might help to avoid fatty or fried foods, eat small meals and snacks and take regular sips of water. Relaxation techniques might also help.

It is important to take anti sickness medicines as prescribed even if you don’t feel sick. It is easier to prevent sickness rather than treat it once it has started.

Tummy (abdominal) pain

Tell your treatment team if you have this. They can check the cause and give you medicine to help. 

Skin rash

Skin problems include a skin rash, dry skin and itching. This usually goes back to normal when your treatment finishes. Your healthcare team can tell you what products you can use on your skin to help.

Less commonly you may have skin sensitivity to sunlight.

Sweating and chills

Let your doctor know if you are sweating more than normal or have chills. They may be able to prescribe medicines to help.

Loss of appetite

You might lose your appetite for various reasons while having cancer treatment. Sickness, taste changes or tiredness can put you off food and drinks.


Contact your advice line if you have diarrhoea. For example, in one day you have 2 or more loose bowel movements than usual. If you have a stoma, you might have more output than normal. Your doctor may give you anti diarrhoea medicine to take home with you after treatment.

Try to eat small meals and snacks regularly. It’s best to try to have a healthy balanced diet if you can. You don’t necessarily need to stop eating foods that contain fibre. But if your diet is normally very high in fibre, it might help to cut back on high fibre foods such as beans, nuts, seeds, dried fruit, bran and raw vegetables. 

Drink plenty to try and replace the fluid lost. Aim for 8 to 10 glasses per day.


Let your doctor or nurse know if you have headaches. They can give you painkillers such as paracetamol to help.

Joint and muscle pain

You might feel some pain from your muscles and joints. Speak to your doctor or nurse about what painkillers you can take to help with this.

Liver changes 

You might have liver changes that are usually mild and unlikely to cause symptoms. They usually go back to normal when treatment finishes. You have regular blood tests to check for any changes in the way your liver is working.

Let your doctor or nurse know straight away if you have yellowing of the skin or whites of the eyes.

Lung problems

You may have lung problems with coughing and less commonly wheezing. Let your healthcare team know straight away if this happens. 

Occasionally you might have shortness of breath or asthma.

Kidney damage

To help prevent kidney damage, it is important to drink plenty of water. You might also have fluids into your vein before, during and after treatment. You have blood tests before your treatments to check how well your kidneys are working. You might also have fluids into your vein before and after your treatment to help prevent this.

High temperature (fever)

If you get a high temperature, let your healthcare team know straight away. Ask them if you can take paracetamol to help lower your temperature.

Damage to the brain or nervous system

This may include symptoms such as muscle weakness, headaches, vision problems or behavioural changes. Talk to your healthcare team if you notice any of these changes.

Less commonly you might have swelling in the brain.

Bleeding from the back passage

You might notice bleeding from your back passage or blood in your poo. Or you might have changes to your normal bowel habit.

Let your healthcare team know if you notice this.

Problems with your urinary system or reproductive organs

You may have problems with your urinary system or reproductive organs (genitourinary system Open a glossary item). Symptoms might include pain when you wee (urinate), trouble emptying your bladder or pain during or after sex.

Talk to your healthcare team if you notice any of these symptoms.

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (1 to 10%). You might have one or more of them. They include:

  • changes to your mood which may make you feel depressed, more anxious and nervous
  • strange dreams
  • taste changes
  • dry mouth
  • confusion and memory loss
  • red and sore gums, mouth, tongue or lips and you might have problems with your teeth
  • seizures (fits), twitching or shaking of the body
  • hair thinning or loss
  • eye problems such as dry, painful eyes and sensitivity to light
  • ear problems such as pain, loss of hearing or ringing in the ears (tinnitus)
  • coordination problems, balance problems or dizziness
  • changes to heart muscle which can cause you to have a fast or slow heart rate, changes to your heart rhythm and chest pain
  • a second cancer such as skin cancer or leukaemia
  • swollen or enlarged glands (lymph nodes) or spleen
  • weight gain or weight loss
  • erection problems and loss of interest in sex
  • periods stopping
  • breast mass or lump
  • changes to levels of minerals, enzymes and salts in your blood. You’ll have regular blood tests during treatment to check this
  • indigestion or heartburn
  • difficulty sleeping
  • constipation
  • numbness or tingling in fingers and toes
  • low or high blood pressure
  • swelling of your hands and feet or other parts of your body such as your voice box (larynx)
  • loss of fluid in your body (dehydration)
  • high levels of uric acid in your body (gout)
  • blood clots that are life threatening; signs are pain, swelling and redness where the clot is. Feeling breathless can be a sign of a blood clot on the lung. Contact your advice line or doctor straight away if you have any of these symptoms
  • graft versus host disease if you have had a stem cell transplant - the donated marrow (graft) reacts against the person receiving the marrow (the host) it can cause diarrhoea, skin rashes and liver damage
  • seeing, smelling, tasting or feeling things that appear to be real but are in your mind (hallucinations)
  • difficulty speaking due to weakness in your speech muscles
  • feeling very restless
  • neck stiffness with headache and dislike of bright lights
  • inflammation or damage to nerves
  • loss of ability to move some or all of your body
  • fainting
  • a sensation that the room or environment is spinning (vertigo)
  • reduced sensitivity to touch
  • uncontrolled bleeding (haemorrhage)
  • inflammation of a vein or blood vessels
  • swallowing problems
  • passing wind (farting)
  • food not moving through the bowel
  • feeling generally unwell

Rare side effects

These side effects happen in fewer than 1 in 100 people (fewer than 1%). You might have one or more of them. They include:

  • inflammation of the eyelids causing red, itchy, swollen, and crusty eyelids
  • bladder infection causing pain and discomfort when passing urine, needing to go more urgently and dark, cloudy and strong smelling urine
  • breathing problems such as a collapsed lung (pneumothorax), and fluid around your lung
  • inflammation of your intestines (bowel) causing you to have diarrhoea
  • bleeding disorders such as idiopathic thrombocytopenia purpura (ITP)
  • severe allergic reaction that can be life threatening
  • heart attack or disease of the heart muscle
  • high levels of uric acid and other substances in your body due to a break down of tumour cells (tumour lysis syndrome) - you have medicines to prevent this when you first start treatment
  • severe skin reaction that may start as tender red patches which leads to peeling or blistering of the skin. You might also feel feverish and your eyes may be more sensitive to light. This is serious and could be life threatening

Coping with side effects

We have more information about side effects and tips on how to cope with them.

What else do you need to know?

Other medicines, foods and drink

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Pregnancy and contraception

This treatment may harm a baby developing in the womb. It is important not to become pregnant or get someone pregnant while you're having treatment and for at least 6 months afterwards.

Talk to your doctor or nurse about effective contraception before starting treatment. Let them know straight away if you or your partner become pregnant while having treatment. 

Loss of fertility 

It is not known whether this treatment affects fertility Open a glossary item in people. Talk to your doctor before starting treatment if you think you may want to have a baby in the future.


Don’t breastfeed during this treatment because the drug may come through into your breast milk.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.


Don’t have immunisations with live vaccines while you’re having treatment and for up to 12 months afterwards. The length of time depends on the treatment you are having. Ask your doctor or pharmacist how long you should avoid live vaccinations.

In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and one of the shingles vaccines called Zostavax.

You can have:

  • other vaccines, but they might not give you as much protection as usual
  • the flu vaccine (as an injection)
  • the coronavirus (COVID-19) vaccine - talk to your doctor or pharmacist about the best time to have it in relation to your cancer treatment

Members of your household who are aged 5 years or over are also able to have the COVID-19 vaccine. This is to help lower your risk of getting COVID-19 while having cancer treatment and until your immune system Open a glossary item recovers from treatment.

Contact with others who have had immunisations - You can be in contact with other people who have had live vaccines as injections. Avoid close contact with people who have recently had live vaccines taken by mouth (oral vaccines) such as the oral typhoid vaccine. Sometimes people who have had the live shingles vaccine can get a shingles type rash. If this happens they should keep the area covered.

If your immune system is severely weakened, you should avoid contact with children who have had the flu vaccine as a nasal spray as this is a live vaccine. This is for 2 weeks following their vaccination.

Babies have the live rotavirus vaccine. The virus is in the baby’s poo for about 2 weeks and could make you ill if your immunity is low. Get someone else to change their nappies during this time if you can. If this isn't possible, wash your hands well after changing their nappy.

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

Related links