Zejula (Niraparib) - Oral


Zejula has the potential to cause harm to an unborn fetus and should not be taken during pregnancy.

It also carries the risk of causing bone marrow disorders such as myelodysplastic syndrome or a type of leukemia called acute myeloid leukemia.

What Is Zejula?

Zejula (niraparib) is an oral cancer medication called a poly (ADP-ribose) polymerase (PARP) inhibitor. It is used in adults to treat certain types of cancer that affect the ovaries and fallopian tubes.

PARP is an enzyme that repairs DNA damage in cells. By blocking PARP from working in cancer cells, they are prevented from repairing the DNA, which causes the cancer cell to die. 

Zejula comes in capsule form.

Drug Facts

Generic Name: Niraparib

Brand Name(s): Zejula

Drug Availability: Prescription

Administration Route: Oral

Therapeutic Classification: Antineoplastic agent

Available Generically: No

Controlled Substance: N/A

Active Ingredient: Niraparib

Dosage Form(s): Capsule

What Is Zejula Used For?

The Food and Drug Administration (FDA) approved Zejula to treat ovarian cancer, which can also include cancer in the fallopian tubes and the pelvis area called the peritoneum. It is used as maintenance therapy, usually following an initial round of treatment for cancer.

Zejula can be used to:

  • Prevent cancer from recurring in people who have received and responded to their primary chemotherapy (maintenance therapy)
  • Treat ovarian cancer recurring after previous treatment with chemotherapy
  • Treat ovarian cancer that has a BRCA mutation after at least three chemotherapy treatments

Evidence supports the use of Zejula as first-line maintenance therapy for advanced ovarian cancer to help prevent a recurrence. For example, a recent placebo-controlled phase 3 trial in people with newly diagnosed advanced ovarian cancer found that the drug significantly reduced the risk of disease progression or death when used as first-line maintenance therapy in people who responded to platinum-based chemotherapy.

Zejula (Niraparib) Drug Information: Female reproductive system

Verywell / Zoe Hansen

How to Take Zejula

Zejula should be taken once a day, around the same time every day. It can be taken with or without food. Only swallow the capsules whole; do not open or crush them.

Zejula can sometimes cause nausea as a side effect. Taking your dose at bedtime can help reduce nausea symptoms.


Store Zejula at room temperature (between 68 and 77 degrees F) and keep it in its original container. It is important to keep your medication away from the reach of children.

How Long Does Zejula Take to Work?

Zejula may be given for a few months to allow it time to work before the oncologist orders any imaging studies to check the progression of your cancer and how well the medication is working.

What Are the Side Effects of Zejula?

This is not a complete list of side effects and others may occur. A healthcare provider can advise you on side effects. If you experience other effects, contact your healthcare provider. You may report side effects to the FDA at fda.gov/medwatch or 1-800-FDA-1088.

Common Side Effects

As with most medications, side effects can occur while taking Zejula.

The most common side effects of Zejula include:

  • Nausea and vomiting
  • Constipation
  • Mouth sores
  • Heartburn or indigestion
  • Diarrhea
  • Muscle pain
  • Back pain
  • Abdominal pain
  • Irregular heartbeat
  • Rash
  • Sore throat
  • Cough
  • Shortness of breath
  • Feeling tired
  • Dry mouth
  • Taste changes
  • Dizziness
  • Headache 
  • Trouble sleeping
  • Abnormal liver tests

Severe Side Effects

Call your healthcare provider right away if you experience any serious side effects from Zejula. Call 911 if you feel your symptoms are life-threatening. Serious side effects and their symptoms can include the following:

  • High blood pressure
  • Posterior reversible encephalopathy syndrome (PRES): Headache, vision changes, seizure, confusion
  • Myelosupression (low blood counts): This can include low white blood cells, red blood cells, and platelets

Long-Term Side Effects

Taking Zejula can potentially increase the risk of developing a bone marrow disorder, myelodysplastic syndrome, or acute myeloid leukemia

Signs and symptoms of these conditions can include:

  • Weight loss
  • Severe fatigue
  • Weakness
  • Frequent infections
  • Fever
  • Trouble breathing
  • Easy bleeding or bruising

Report Side Effects

Zejula may cause other side effects. Call your healthcare provider if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your healthcare provider may send a report to the FDA's MedWatch Adverse Event Reporting Program or by phone (800-332-1088).

Dosage: How Much Zejula Should I Take?

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The dose of this medicine will be different for different patients. Follow your doctor's orders or the directions on the label. The following information includes only the average doses of this medicine. If your dose is different, do not change it unless your doctor tells you to do so.

The amount of medicine that you take depends on the strength of the medicine. Also, the number of doses you take each day, the time allowed between doses, and the length of time you take the medicine depend on the medical problem for which you are using the medicine.

  • For oral dosage form (capsules):
    • For first-line maintenance treatment of advanced ovarian cancer, fallopian tube cancer, or primary peritoneal cancer:
      • Adults—Dose is base on body weight or platelet count and must be determined by your doctor:
        • Weighs 77 kilograms (kg) or more, or platelet count 150,000 microliters (µL) or more—300 milligrams (mg) (three 100 mg capsules) once a day. Your doctor may adjust your dose as needed and tolerated.
        • Weighs less than 77 kilograms (kg) or platelet count less than 150,000 microliters (µL)—200 milligrams (mg) (two 100 mg capsules) once a day. Your doctor may adjust your dose as needed and tolerated.
      • Children—Use and dose must be determined by your doctor.
    • For maintenance treatment of advanced or recurrent ovarian cancer, fallopian tube cancer, or primary peritoneal cancer:
      • Adults—300 milligrams (mg) (three 100 mg capsules) once a day. Your doctor may adjust your dose as needed and tolerated.
      • Children—Use and dose must be determined by your doctor.


You may need a dose modification of Zejula if you experience side effects that aren’t well controlled or if you have liver disease.

Missed Dose

If you miss your dose of Zejula, take it at the next scheduled time. Do not double up on doses to make up for the missed dose.

Zejula can sometimes cause nausea as a side effect. If you vomit after taking a dose, do not take an extra dose. Take your next dose at the scheduled time.

Overdose: What Happens If I Take Too Much Zejula?

Contact your cancer care team immediately if you take more than the prescribed amount of Zejula. 

What Happens If I Overdose on Zejula?

If you think you or someone else may have overdosed on Zejula, call a healthcare provider or the Poison Control Center (800-222-1222).

If someone collapses, has a seizure, has trouble breathing, or can’t wake up after taking too much Zejula, call 911 immediately.


Drug Content Provided and Reviewed by IBM Micromedex®

It is very important that your doctor check your progress at regular visits. This will allow your doctor to see if the medicine is working properly and to decide if you should continue to take it. Blood tests may be needed to check for unwanted effects.

Using this medicine while you are pregnant can harm your unborn baby. If you are a woman who can get pregnant, your doctor may do tests to make sure you are not pregnant before starting treatment. Use an effective form of birth control to keep from getting pregnant during treatment and for at least 6 months after the last dose of this medicine. If you think you have become pregnant while using the medicine, tell your doctor right away.

This medicine may cause bone marrow problems, including myelodysplastic syndrome or acute myeloid leukemia. Check with your doctor right away if you have a fever, blood in the urine or stool, chills, unusual bleeding, bruising, tiredness, or weakness, or weight loss.

Niraparib can temporarily lower the number of white blood cells in your blood, increasing the chance of getting an infection. It can also lower the number of platelets, which are necessary for proper blood clotting. If this occurs, there are certain precautions you can take, especially when your blood count is low, to reduce the risk of infection or bleeding:

  • If you can, avoid people with infections. Check with your doctor immediately if you think you are getting an infection or if you get a fever or chills, cough or hoarseness, lower back or side pain, or painful or difficult urination.
  • Check with your doctor immediately if you notice any unusual bleeding or bruising, black, tarry stools, blood in the urine or stools, or pinpoint red spots on your skin.
  • Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.
  • Do not touch your eyes or the inside of your nose unless you have just washed your hands and have not touched anything else in the meantime.
  • Be careful not to cut yourself when you are using sharp objects such as a safety razor or fingernail or toenail cutters.
  • Avoid contact sports or other situations where bruising or injury could occur.

If you plan to have children, talk with your doctor before using this medicine. Some men using this medicine have become infertile (unable to have children).

Your doctor will check your blood pressure on a regular basis while you are using this medicine. You might need to monitor your blood pressure at home. Tell your doctor right away if you have a severe headache, lightheadedness, or changes in your vision.

Check with your doctor right away if you have agitation, back pain, blurred vision, change in consciousness, confusion, dizziness, drowsiness, fever, hallucinations, headache, irritability, loss of consciousness, mood or mental changes, seizures, stiff neck, unusual tiredness or weakness, or vomiting. These may be symptoms of a serious nervous system problem called posterior reversible encephalopathy syndrome (PRES).

Do not take other medicines unless they have been discussed with your doctor. This includes prescription or nonprescription (over-the-counter [OTC]) medicines and herbal or vitamin supplements.

What Are Reasons I Shouldn’t Take Zejula? 

Do not take Zejula during pregnancy, as it can cause harm or death to the unborn fetus. Avoid taking Zejula while breastfeeding, as well.

People who are allergic to FD&C Yellow No. 5 (an artificial food coloring commonly used to dye tablets and capsules) should not take Zejula.

What Other Medications Interact With Zejula?

No studies specifically looking at drug interactions with Zejula have been done. 

However, any medication that could cause similar serious side effects as Zejula may need to be reviewed by your healthcare provider.

What Medications Are Similar?

In addition to Zejula, other PARP inhibitor medications include:

  • Lynparza (olaparib), which is used to treat ovarian, breast, prostate, and pancreatic cancer. 
  • Rubraca (rucaparib), which is used for ovarian and prostate cancers.
  • Talzenna (talazoparib), which is used to treat breast cancer. 

These medications should not be taken along with Zejula. 

Frequently Asked Questions

  • What is Zejula used for?

    Zejula is used to treat advanced ovarian cancer in people who have previously received a type of chemotherapy called platinum chemotherapy. It is typically used to prevent cancer from recurring after a person has responded to chemotherapy.

  • How does Zejula work?

    Zejula is a PARP inhibitor. It blocks the action of the PARP enzyme in cancer cells. The PARP enzyme repairs the DNA in a cell, and by blocking it, the cancer cell dies.

  • What are the side effects of Zejula?

    Some side effects from Zejula can include the following:

    • Nausea and vomiting
    • Fatigue
    • Constipation or diarrhea
    • Headache
    • Dizziness
    • Muscle pain
    • Rash
    • High blood pressure
    • Low blood counts
  • How to stop taking Zejula?

    Do not stop taking Zejula unless instructed by your oncologist.

How Can I Stay Healthy While Taking Zejula?

Zejula can be an effective part of your cancer medication plan. It can help treat ovarian cancer and keep it from returning when used as maintenance therapy. 

When starting your cancer treatment, it is important to communicate with your cancer care team about any questions, concerns, or feelings you have. They can help you navigate your cancer journey. 

Talk to your healthcare providers if you’re experiencing any side effects from the medication. They can help provide you with tips to manage your symptoms. 

Medical Disclaimer

Verywell Health's drug information is meant for educational purposes only and is not intended to replace medical advice, diagnosis, or treatment from a healthcare provider. Consult your healthcare provider before taking any new medication(s). IBM Watson Micromedex provides some of the drug content, as indicated on the page.

6 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Food and Drug Administration. Zejula label.

  2. National Cancer Institute. PARP inhibitor.

  3. Lee A. Niraparib. A review in first-line maintenance therapy in advanced ovarian cancer. Targeted Oncology. 2021. doi:10.1007/s11523-021-00841-2

  4. Food and Drug Administration. Lynparza label.

  5. Food and Drug Administration. Rubraca label.

  6. Food and Drug Administration. Talzenna label.

By Julie Scott, MSN, ANP-BC, AOCNP
Julie is an Adult Nurse Practitioner with oncology certification and a healthcare freelance writer with an interest in educating patients and the healthcare community.