Pembrolizumab, capecitabine and oxaliplatin

Before starting this treatment, you should have a blood test to check for gene changes that affect how your body produces DPD. DPD is an enzyme that helps the body break down capecitabine. 

If you have low DPD levels or no DPD (DPD deficiency), you have more risk of serious or life-threatening side effects from capecitabine. To reduce your risk, your doctor may give you:

• a lower dose of capecitabine to start with
• a different type of chemotherapy.

Having low DPD levels does not usually cause any symptoms. Without a test, you will not know whether your DPD levels are low. Testing finds most people who are affected, but not all. Your doctor, nurse or pharmacist can give you more information about your risk of DPD deficiency, before you start treatment.

We explain the most common side effects of this treatment here. We also include some that are less common.

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here. 

Always tell your doctor, nurse or pharmacist about any side effects you have. They can give you: 

• drugs to help control some side effects
• advice about managing side effects. 

It is important to take any drugs exactly as explained. This means they will be more likely to work for you. 

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

If your body does not produce enough of an enzyme called DPD, you may have a higher risk of severe or life-threatening side effects.

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

They will also give you a card with information about your treatment. It is important to keep the card with you during treatment and after treatment ends. You should show it to any doctor or healthcare professional caring for you.

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If your white blood cell count is low, you may be more likely to get an infection. A low white blood cell count is called neutropenia.

An infection can be very serious when the number of white blood cells is low. It is important to get any infection treated as soon as possible. If you have any of the following symptoms, contact the hospital straight away on the 24-hour number:

• a temperature above 37.5°C  
• a temperature below 36°C 
• you feel unwell, even with a normal temperature
• you have symptoms of an infection.

Symptoms of an infection include:

• feeling shivery and shaking
• a sore throat
• a cough 
• breathlessness
• diarrhoea
• needing to pass urine (pee) often, or discomfort when you pass urine.

It is important to follow any specific advice your cancer treatment team gives you.

Your white blood cell count will usually return to normal before your next treatment. You will have a blood test before having more treatment. If your white blood cell count is low, your doctor may delay your treatment for a short time, until your cell count increases.

This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot.

If the number of platelets is low, you may bruise or bleed easily. You may have:

• nosebleeds
• bleeding gums
• heavy periods
• blood in your urine (pee) or stools (poo)
• tiny red, brown or purple spots that may look like a rash – these spots can be harder to see if you have black or brown skin. 

If you have any unexplained bruising or bleeding, contact the hospital straight away on the 24-hour number. You may need a drip to give you extra platelets. This is called a platelet transfusion.

This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may feel:

• very low in energy
• breathless 
• dizzy and light-headed. 

If you have these symptoms, contact the hospital straight away on the 24-hour number. You may need treatment for anaemia. If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

Capecitabine may cause diarrhoea. Sometimes it is severe. Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. If you have a stoma, it will be more active than usual. Your doctor, nurse or pharmacist may give you anti-diarrhoea drugs to take at home.

If you have diarrhoea or an increase in stoma activity, follow their advice on:

• taking the anti-diarrhoea drugs 
• how much and what type of fluids to drink 
• any changes to your diet that might help. 

After this, contact the hospital on the 24-hour number straight away if:

• you have diarrhoea at night 
• you have uncomfortable stomach cramps
• you have diarrhoea 4 or more times in a day 
• you have a moderate increase in stoma activity
• the anti-diarrhoea drugs do not work within 24 hours.

They will tell you to stop taking capecitabine. When the diarrhoea is better, they will tell you whether you can start taking it again. Sometimes they reduce the dose.

This treatment may affect the nerves in your fingers and toes. This can cause numbness, tingling or pain in your hands or feet. This is called peripheral neuropathy. You might find it hard to do fiddly tasks such as fastening buttons or tying shoelaces.

If you have these symptoms, always tell your doctor, nurse or pharmacist. They sometimes need to change the drug or the dose of the drug. The symptoms usually improve slowly after treatment ends. But for some people they continue and are a long-term side effect of treatment.

This treatment can affect the palms of your hands and the soles of your feet. This is called palmar-plantar or hand-foot syndrome.

If you have white skin these areas may become red. If you have black or brown skin, these areas might get darker.

The skin on the palms of your hands and the soles of your feet may:

• be sore
• be painful, tingle, or swell
• peel, crack or blister.

If you have any of these symptoms, contact the hospital straight away on the 24-hour number. They can give you advice. This is especially important if you have any broken skin or if walking is difficult. They can prescribe creams and painkillers to help.

You can care for your hands and feet by:

• gently moisturising your hands and feet regularly
• wearing gloves to protect your hands and nails when working in the house or garden
• wearing loose cotton socks and avoiding tight-fitting shoes and gloves.

Your doctor, nurse or pharmacist will prescribe anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as they tell you to, even if you do not feel sick. It is easier to prevent sickness than to treat it after it has started.

If you feel sick, take small sips of fluid often and eat small amounts regularly. It is important to drink enough fluids. If you continue to feel sick, or if you are sick (vomit) 1 to 2 times in 24 hours, contact the hospital on the 24-hour number as soon as possible. They will give you advice. They may change your anti-sickness treatment. Let them know if you still feel sick.

Some foods may taste different or have no taste. Try different foods to find out what tastes best to you. You may also get a bitter or metallic taste in your mouth. Your doctor, nurse or pharmacist can give you advice. It might help to try:

• sucking sugar-free sour or boiled sweets
• eating cold foods
• eating sharp-tasting fresh fruit.

Taste changes usually get better after treatment ends. We have more information about coping with changes to taste.

This treatment may cause a sore mouth and throat. You may also get mouth ulcers. This can make you more likely to get a mouth or throat infection. Use a soft toothbrush to clean your teeth or dentures in the morning, at night and after meals.

Contact the hospital straight away on the 24-hour number, if:

• a sore mouth or throat affects how much you can drink or eat 
• your mouth, tongue, throat or lips have any blisters, ulcers or white patches. 

They can give you advice, and mouthwash or medicines to help with the pain or to treat any infection. Follow their advice and make sure you:

• drink plenty of fluids
• avoid alcohol and tobacco
• avoid food or drinks that irritate your mouth and throat.

This treatment can affect your appetite. Don’t worry if you do not eat much for 1 or 2 days. But if your appetite does not come back after a few days, or if you are losing weight, tell your doctor, nurse or pharmacist. They can give you advice. They may give you food or drink supplements. Or they may suggest changes to your diet or eating habits to help.

Your hair may get thinner. But you are unlikely to lose all the hair from your head. Hair loss usually starts after your first or second treatment. It is almost always temporary, and your hair will usually grow back after treatment ends. 

Your nurse can talk to you about ways to cope with hair loss.

Pembrolizumab and capecitabine can both affect how the heart works. This is not common, but it can be serious. You may have tests to check how well your heart is working. These may be done before, during and after treatment.

Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

• breathlessness
• dizziness
• changes to your heartbeat
• swollen feet and ankles.

If you are still taking capecitabine and you have any of these symptoms, stop taking the capecitabine tablets. Do not start taking it again until your doctor, nurse or pharmacist tells you to.

Always call 999 if you have:

• chest pain, pressure, heaviness, tightness or squeezing across the chest
• difficulty breathing.

Oxaliplatin may cause you discomfort when you pass urine. You may also pass urine more often than usual. Make sure you drink plenty of fluids during the 24 hours following chemotherapy. Try to drink at least 2 litres (3½ pints).

It is also important to empty your bladder regularly and to try to pass urine as soon as you feel the need to go.

Contact the hospital straight away if you feel any discomfort or stinging when you pass urine, or if you notice any blood in it.

This treatment may cause hearing changes, including hearing loss. You may have ringing in the ears. This is called tinnitus. You may also become unable to hear some high-pitched sounds. Hearing changes may get better after this treatment ends. But this does not always happen. If you notice any changes in your hearing, tell your doctor, nurse or pharmacist.

Pembrolizumab can make the immune system too active. This can cause the following side effects. Some of them are rare. But it is important to know about them.

Side effects can become serious if they are not treated. They can start weeks, months, or sometimes more than a year after you finish treatment.

Do not try to treat these side effects yourself. If you have these side effects during treatment or after it ends, always contact the hospital straight away on the 24-hour number.

Your patient alert card has information about your pembrolizumab treatment. Remember to keep the card with you during treatment and after treatment ends. You should show it to any doctor or healthcare professional caring for you.

This treatment can cause inflammation of the lungs. This is called pneumonitis. Contact the hospital straight away on the 24-hour number if you notice any of these changes during treatment or after it ends:

• breathlessness
• a cough that does not go away
• wheezing
• a fever, with a temperature over 37.5°C.

You should also tell them if any existing breathing problems get worse. You may have tests to check your lungs. You may need steroids or other treatments.

Diarrhoea can be a side effect of capecitabine. It is also a possible serious side effect of pembrolizumab.

Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. If you have a stoma, it may be more active than usual.

Contact the hospital straight away on the 24-hour number if you have any of the following symptoms during treatment, or after treatment ends:

• You have diarrhoea 4 or more times in a day.
• You have a moderate increase in stoma activity.
• You have uncomfortable tummy cramps.
• You have diarrhoea at night.
• Your temperature is over 37.5°C.
• There is blood or mucus in your stool.

You may need to go into hospital to have fluids through a drip, or treatments such as steroids.

This treatment can cause kidney inflammation and may affect how the kidneys work. This is called nephritis. This is not common, but if it is not treated it can become serious. You will have regular blood tests to check how your kidneys are working. If tests show kidney changes, you may have steroids or other treatments.

Contact the hospital straight away on the 24-hour number during treatment, or after it ends, if you either:

• have blood in your urine (pee) 
• are passing less urine or peeing less often than usual.

This treatment can cause liver inflammation and may affect how your liver works. This is called hepatitis. You will have regular blood tests to check this. If the blood tests show liver changes, you may have steroids.

Sometimes liver changes can be serious. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during treatment or after it finishes:

• yellow skin or eyes
• feeling very sleepy
• dark urine (pee)
• unexplained bleeding or bruising
• pain in the right side of your tummy (abdomen)
• loss of appetite.

This treatment may cause inflammation in the skin. This is usually mild, but can if it is not treated it can become serious. You may need creams, steroids or other medicines to treat skin problems. If you notice skin changes during treatment, or after treatment ends, contact the hospital on the 24-hour number as soon as possible. Skin changes can include: 

• a rash or bumps on the skin
• dry or itchy skin
• patches of white or paler skin.

To protect your skin from the sun, use suncream with of at least SPF 30. SPF stands for sun protection factor. Cover up with clothing and a hat. 

Contact the hospital straight away on the 24-hour number if you have any of these symptoms:

• a rash that is spreading
• blistering or peeling skin
• flu-like symptoms, such as a high temperature and joint pain. 

These symptoms can be a sign of a serious skin reaction that needs to be treated immediately in hospital.

This treatment can cause sore or weak muscles. Your joints may also be stiff, sore or swollen (arthritis). If you already have problems with joint pain, this may become worse. Contact the hospital on the 24-hour number if you have any of these symptoms during treatment or after it ends:

• new or worsening aches or pains
• new or worsening stiffness in a joint
• swollen joints.

You may need steroids or other treatments, such as painkillers.

Rarely, this treatment can affect the brain and nerves. These effects may be mild at first, but can become serious if they are not treated. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during treatment or after it ends:

• any weakness, numbness or tingling in your arms, legs or face
• a headache that does not get better
• dizziness
• drowsiness or confusion
• problems with moving or speaking
• any unexplained pain in other parts of your body.

You may need steroids and other treatments.

This treatment may affect your hormones. Hormones control many different processes in the body. You will have regular blood tests to check some of your hormone levels. Contact the hospital on the 24-hour number if you have any of these side effects during treatment or after it ends:

• increased sweating
• weight gain or weight loss
• dizziness or fainting
• feeling more hungry or thirsty than usual
• loss of sex drive
• passing urine (peeing) more often than usual
• headaches that do not go away
• feeling more tired than usual (fatigue)
• mood changes.

You may need drugs to control your hormone levels.

This treatment may raise your blood sugar levels and increase the risk of diabetes. 

You will have regular blood tests to check this. 

Signs of raised blood sugar include:

• feeling thirsty
• needing to pass urine (pee) more often than usual
• feeling more tired than usual.

Contact the hospital on the 24-hour number if you have these symptoms during treatment or after it ends.

If you already have diabetes, your blood sugar levels may be higher than usual. You may need advice and support from your GP or diabetes team about managing this.

This treatment can affect your eyes and eyesight. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during treatment or after it ends:

• sore, painful, or swollen eyes
• eyes that are sensitive to light
• changes to your eyesight.

You may need steroids or other treatments. A specialist eye doctor (ophthalmologist) may also need to check your eyes.

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