What is olaparib?

Olaparib is used to treat:

It may sometimes be used to treat other cancers. It is best to read the information about this drug with our general information about targeted therapy drugs and the type of cancer you have. 

Olaparib belongs to a group of targeted therapy drugs called cancer growth inhibitors. Olaparib is also known as a PARP inhibitor. PARPs are proteins that help damaged cells repair themselves.

Olaparib blocks (inhibits) how PARP proteins work. Without PARP proteins, cancer cells may become too damaged to survive, and die. 

Your cancer doctor will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment.

More information about this treatment

This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.

You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.

How olaparib is given?

Olaparib comes as tablets, so you can take it at home. It can be given on its own or with other cancer drugs.  

During a course of treatment, you usually see a:

  • cancer doctor
  • cancer nurse or specialist nurse
  • specialist pharmacist.

This is who we mean when we mention doctor, nurse or pharmacist in this information.

You will have regular blood tests during treatment. This is to check that your kidneys are working and that your blood cells are at a safe level to have treatment. 

You will speak to a doctor, nurse or pharmacist regularly during treatment. They will talk to you about your blood results and ask how you have been feeling.  

They will give you the tablets to take home. They may also give you anti-sickness drugs and other medicines to take home. Take all your capsules or tablets exactly as they have been explained to you. This is important to make sure they work as well as possible for you. 

Taking olaparib capsules

Take your tablets 2 times a day, 12 hours apart. This should be once in the morning and once in the evening. You can take them with or without food. Swallow them whole with a glass of water. Do not chew, dissolve, crush, or break them. 

You should avoid having grapefruit or grapefruit juice while you are taking olaparib. It can affect how the drug works. 

You may be given tablets of different strengths. Always take them exactly as your doctor, nurse or pharmacist has explained. This is important to make sure they work as well as possible for you. If you forget to take your tablets, do not take a double dose. Take your next dose at the usual time and let your doctor or nurse know.

Other things to remember about your tablets:

  • Olaparib tablets should be kept in the original package and at room temperature, away from heat and direct sunlight.
  • Keep them safe, somewhere children cannot see or reach them.
  • If you are sick just after taking the tablets, contact the hospital. Do not take another dose.
  • If your treatment is stopped, return any unused tablets to the pharmacist. 

Your course of treatment

Your doctor, nurse or pharmacist will discuss your treatment plan with you. They may give you a copy of the treatment plan to take home. 

You keep taking olaparib for as long as your doctor tells you. Do not stop taking it without talking to your doctor. 

About side effects

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

You may get some of the side effects we mention, but you are unlikely to get all of them. If you are also having treatment with other cancer drugs, you may have some side effects that we have not listed here. 

You may have some rarer side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor, nurse or pharmacist can give you drugs to help control some side effects. It is important to take them exactly as they tell you. This means the drugs will be more likely to work for you. Your doctor, nurse or pharmacist will give you advice about managing your side effects.

Serious and life-threatening side effects

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.

Contact the hospital

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.

Common side effects of olaparib

Risk of infection

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.

You will have regular blood tests during treatment. If your white blood cell count is low, your doctor may stop your treatment for a short time, until your cell count increases. Sometimes they will reduce the dose of your treatment.

Anaemia (low number of red blood cells)

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.

Bruising and bleeding

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.

Feeling sick

Your doctor can prescribe anti-sickness drugs to help prevent or control sickness. Take the drugs exactly as your nurse or pharmacist tells you. If you feel sick, take small sips of fluids often and eat small amounts regularly. It is important to drink enough fluids. 

If you continue to feel sick or are sick (vomit) more than once in 24 hours, contact the hospital as soon as possible. They will give you advice. Your doctor or nurse may change the anti-sickness drug to one that works better for you.

Diarrhoea

This treatment may cause diarrhoea. Diarrhoea means passing more stools (poo) than is normal for you, or having watery or loose stools. You may also have stomach cramps. If you have a stoma, it may be more active than usual. 

If you are passing loose stools 3 or more times a day and this is not normal for you, contact the hospital as soon as possible on the 24-hour number. Follow the advice they give you about:

  • taking anti-diarrhoea medicines 
  • drinking enough fluids to keep you hydrated and to replace lost salts and minerals
  • any changes to your diet that might help. 

They might also ask you for a specimen of your stool to check for infection.

Tummy pain

You may get pain in your tummy (abdomen), or have indigestion. Your doctor, nurse or pharmacist can give you advice or treatment to help. Contact the hospital straight away on the 24-hour number if your symptoms do not go away, or get worse.

Changes to your taste

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.

Loss of appetite

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.

Feeling tired (fatigue)

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest between activities.

Being physically active can help to manage tiredness and give you more energy. It also:

  • helps you sleep better
  • reduces stress
  • improves your bone health.

If you feel sleepy, do not drive or operate machinery.

Headaches

This treatment may cause headaches. If you have headaches, tell your doctor, nurse or pharmacist. They can give you advice about painkillers that may help. Tell them if the headache does not get better, or gets worse.

Dizziness

You may feel dizzy during this treatment. Tell your doctor or nurse if this is difficult to cope with. If you feel dizzy, do not drive or operate machinery.

Sore mouth and throat

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

If your mouth or throat is sore:

  • tell your nurse or doctor – they can give you a mouthwash or medicines to help
  • try to drink plenty of fluids
  • avoid alcohol, tobacco and foods that irritate your mouth and throat.

Rash

Olaparib may cause an itchy rash and the skin may become raised and red. Tell your doctor or nurse if this happens. They can give you advice on looking after your skin and creams that you can use.

Effects on the lungs

This treatment can cause changes to the lungs. Contact the hospital straight away if you notice any of these changes:

  • breathlessness
  • a cough
  • wheezing
  • a fever, with a temperature over 37.5°C (99.5°F).

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

Less common side effects of olaparib

Second cancer

Some cancer drugs can increase the risk of developing other types of cancer or leukaemia later in life. This is rare. The benefits of treatment usually far outweigh this risk. Your doctor can talk to you about this.

Effects on the liver

This treatment may affect how your liver works. This is usually mild. You will have blood tests to check how well your liver is working.

Other information

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

  • throbbing pain or swelling in a leg or arm
  • reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
  • suddenly feeling breathless or coughing.

Always call 999 if you have:

  • chest pain
  • difficulty breathing.

A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.

Other medicines

Some medicines can affect how this treatment works or be harmful while you are having it. Always tell your cancer doctor, nurse or pharmacist about any drugs you are taking or planning to take, such as: 

Vaccinations

Doctors usually recommend that people with cancer have vaccinations for flu and for coronavirus (covid). These help reduce your risk of serious illness from these infections. Most people can have these vaccines, including people with weak immune systems.

If your immune system is weak, you should not have live vaccinations. Live vaccines can make you unwell because they contain a very weak version of the illness they will protect you against. Live vaccines include Zostavax®, which is a shingles vaccine, and the yellow fever vaccine.

It is important to ask your doctor, nurse or pharmacist for advice about having vaccinations. They can explain what vaccines are right for you and when it is best to have them.

Fertility

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

Contraception

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

Olaparib may make hormonal contraceptives less effective. If you take the pill or another hormonal contraceptive, talk to your nurse or doctor for more advice.

Breastfeeding

You are advised not to breastfeed while having this treatment, or for some time after treatment ends. This is because the drugs could be passed to the baby through breast milk. 

Your doctor, nurse or pharmacist can give you more information.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.

About our information

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert health professionals and people living with cancer.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 November 2023
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Next review: 01 November 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.