Olaparib (Lynparza) and niraparib (Zejula) belong to a group of targeted cancer tablets called PARP inhibitors. They are used for some ovarian, breast, pancreatic and prostate cancers, especially those linked to changes in the BRCA genes. This guide explains how they work, who they are for, and how the two compare.
What BRCA has to do with it
BRCA1 and BRCA2 are genes that make proteins to repair damaged DNA. People who inherit a harmful change in one of these genes have a higher risk of several cancers, especially breast and ovarian cancer3.
PARP enzymes are part of another DNA repair system1. Cancer cells with harmful BRCA changes, whether inherited or developed during life, already struggle to repair DNA. PARP inhibitors block another repair route, which can make these cancer cells easier to treat3. Some cancers have similar repair problems without a BRCA change. Doctors call this homologous recombination deficiency (HRD), and tests can look for it12.
PARP inhibitors are targeted therapy, not chemotherapy. See our guide is it chemotherapy?
Testing comes first
These medicines are only licensed for people whose cancer, or whose genes, have the right changes. In the US, the labels say to choose patients using an approved test for BRCA, other repair genes (HRR) or HRD, depending on the cancer12. If you have not been tested, ask your team whether testing is right for you. A BRCA change found in your blood may also matter for your relatives3.
Where they are used
| Cancer | Olaparib (Lynparza) | Niraparib (Zejula) |
|---|---|---|
| Ovarian cancer (maintenance after a response to platinum chemotherapy) | Yes, for BRCA changes, or with bevacizumab for HRD-positive cancer1 | Yes, for HRD-positive cancer after first-line treatment, or inherited BRCA changes when cancer comes back2 |
| Breast cancer | Yes, for inherited BRCA changes and HER2-negative cancer, early high-risk or spread1 | Not licensed in the US2 |
| Pancreatic cancer | Yes, maintenance for inherited BRCA changes1 | Not licensed in the US2 |
| Prostate cancer | Yes, for some repair-gene changes after enzalutamide or abiraterone, or with abiraterone for BRCA changes1 | Not on its own in the US2 |
Two other PARP inhibitors, rucaparib and talazoparib, are also approved for certain cancers with BRCA changes3. For prostate cancer, PARP inhibitors are among the options when hormone treatment stops working4. See our guide to abiraterone vs enzalutamide.
How you take them
| Olaparib | Niraparib | |
|---|---|---|
| Usual dose | 300 mg twice a day1 | 200 mg or 300 mg once a day, depending on body weight and platelet count2 |
| Food | With or without food1 | With or without food; taking it at bedtime may help with nausea2 |
| Swallowing | Whole; do not chew, crush, dissolve or divide1 | Whole; do not chew, crush or split2 |
| Missed dose | Take the next dose at the usual time1 | Take the next dose at the usual time2 |
Avoid grapefruit and Seville oranges, and their juices, while taking olaparib1. Men taking olaparib for prostate cancer also need ongoing hormone treatment to keep testosterone low1. Strengths and forms differ between brands, so do not swap one product for another without checking the dose with your pharmacist.
Side effects
- Olaparib: the most common side effects are nausea, tiredness, anaemia (low red blood cells), vomiting, diarrhoea, poor appetite, headache, taste changes, cough, low white cells, breathlessness, dizziness, indigestion and low platelets1.
- Niraparib: the most common are nausea, low platelets, anaemia, tiredness, constipation, muscle and joint pain, stomach pain, vomiting, low white cells, poor appetite, trouble sleeping, headache, breathlessness, rash, diarrhoea and high blood pressure2.
Rare but serious problems include12:
- Bone marrow problems, including the blood disorders myelodysplastic syndrome and acute myeloid leukaemia, which can be fatal. This is why blood counts are checked regularly.
- Lung inflammation (pneumonitis) and blood clots with olaparib.
- High blood pressure and a rare brain swelling condition (PRES) with niraparib.
Tell your team quickly about tiredness that does not improve, breathlessness, frequent infections, unusual bruising or bleeding, a new cough, leg pain or swelling, a severe headache or changes in your vision.
Blood tests and checks
- Olaparib: a full blood count before you start and then monthly1.
- Niraparib: a full blood count every week for the first month, then monthly for the next 11 months, then from time to time. Blood pressure and heart rate at least weekly for the first 2 months, then monthly for the first year2.
If blood counts drop, treatment is usually paused and restarted at a lower dose12. Do not change your dose yourself.
How long treatment lasts
- Olaparib after first-line treatment for BRCA ovarian cancer: up to 2 years. People with no sign of cancer on scans at 2 years stop; others may continue if their doctor thinks it will help1.
- Olaparib for early breast cancer: 1 year1.
- Most other uses: for as long as the medicine is working and the side effects are manageable12.
If the cancer grows, see our guide to when a cancer medicine stops working.
Generic versions and cost
Our generic Lynparza page explains the options. We stock olaparib, including Olanib 150 mg tablets and BDParp 150 mg tablets, and niraparib, including Niranib 100 mg capsules. See all options on our olaparib and niraparib pages, or browse our ovarian cancer, breast cancer and prostate cancer medicines. All need a prescription.
Frequently asked questions
Olaparib or niraparib: which is better?
Neither is better for everyone. Olaparib is licensed for more types of cancer, including breast, pancreatic and prostate cancer, while both are used for ovarian cancer. They also differ in dosing, side effects and checks. Your specialist will choose based on your cancer, your test results and your health.
Is olaparib chemotherapy?
No. Olaparib is a targeted therapy that blocks PARP enzymes involved in DNA repair. It is a tablet, and it works differently from chemotherapy.
How long do you take olaparib?
It depends on the cancer. After first-line treatment for BRCA ovarian cancer it is up to 2 years, and for early breast cancer it is 1 year. For other uses, it usually continues while it is working and the side effects are manageable.
Will olaparib get rid of ovarian cancer?
Olaparib is not described as a cure. It is used as maintenance treatment to help keep ovarian cancer under control after a response to chemotherapy. Your specialist can explain what it may mean for you.
Do I need a BRCA test to take olaparib?
Usually yes. In the US, olaparib is licensed for people whose cancer or genes have specific changes, found by an approved test.
Sources & references
- US National Library of Medicine, DailyMed. Lynparza (olaparib) prescribing information.
- US National Library of Medicine, DailyMed. Zejula (niraparib) prescribing information.
- National Cancer Institute. BRCA Gene Changes: Cancer Risk and Genetic Testing. Reviewed 19 July 2024.
- National Cancer Institute. Hormone Therapy for Prostate Cancer. Reviewed 4 October 2024.
Related reading
This content is for informational purposes only and is not medical advice. PARP inhibitors are prescribed and monitored by a cancer specialist. Used as prescribed by a licensed medical professional.
Mahesh Gupta is a licensed clinical pharmacist with 15 years of experience. He holds a B.Pharm and M.Pharm from LN Mithila University. At OnlineMeds, he reviews medicine and health content to help ensure it is accurate, evidence-based, and easy to understand.