[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [PARP inhibitors](https://durgical.com/en/pharmacology/classes/parp-inhibitors/) › Niraparib # Niraparib ## PARP inhibitors? PARP inhibitors ## High alert? An error with this medicine can cause serious harm: double checks and protocols are used. ## Pregnancy: avoid? Avoid in pregnancy. Can harm the fetus: a pregnancy test is done before starting, effective contraception is used during treatment and for a time afterwards (by women and by men… A once-daily PARP inhibitor used as maintenance in ovarian cancer after a platinum response. Watch platelets and blood pressure. Updated Nov 1, 2026 Also called: MK-4827 ## Quick facts **Group** [PARP inhibitors](https://durgical.com/en/pharmacology/classes/parp-inhibitors/) **Target** Poly(ADP-ribose) polymerases PARP1 and PARP2 **Used for** Maintenance in advanced ovarian **Key effects** Nausea · Thrombocytopenia and anaemia · Fatigue **Monitor** Complete blood count · Neurological symptoms **ATC** L01XK02 No doses: the clinician sets them by the current guideline. On this page - The basics Mechanism of action - Indications - Adverse effects - Pharmacokinetics - Memory aid - Clinical What the labels mean - Safety Contraindications - Key interactions - What is monitored - Administration and safety - Pregnancy and breastfeeding - Nursing care - Study Test yourself - Connections Connections ## Mechanism of action ✂**Poly(ADP-ribose) polymerases PARP1 and PARP2**Niraparib ⓘ The figure shows niraparib in the NAD+ site of the human PARP1 catalytic domain. **Target in 3D:** Poly(ADP-ribose) polymerases PARP1 and PARP2. PDB structure 4R6E (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/4R6E) · Drag to rotate · pinch to zoom Niraparib inhibits PARP1 and PARP2 and traps them on DNA, so single-strand breaks become lethal double-strand breaks in tumours with BRCA mutations or other homologous recombination defects. It also inhibits the dopamine, noradrenaline and serotonin transporters, which explains its effects on blood pressure and heart rate. - Inhibits PARP1/2 and traps them on DNA - Homologous recombination-deficient tumour cells die - Off-target block of monoamine transporters raises BP ## Indications - Maintenance in advanced ovarian, fallopian tube or primary peritoneal cancer after a response to first-line platinum chemotherapy. [Ovarian cancer →](https://durgical.com/en/conditions/ovarian-cancer/) - Maintenance in recurrent disease with germline BRCA mutation after a response to platinum. [Ovarian cancer →](https://durgical.com/en/conditions/ovarian-cancer/) ## Adverse effects ### Common - Nausea, vomiting, constipation, heartburn - Thrombocytopenia and anaemia - Fatigue, headache, dizziness - Trouble sleeping and anxiety - Dry mouth, mouth sores, taste changes ### Serious (rare, important) - Myelodysplastic syndrome and acute myeloid leukaemia (rare, often fatal) - Myelosuppression: anaemia, neutropenia, thrombocytopenia - Hypertension and fast heart rate - Posterior reversible encephalopathy syndrome (headache, confusion, vision changes, seizures) ## Contraindications - No absolute contraindications in the label apart from hypersensitivity; see the warnings ## Key interactions **Other bone-marrow-suppressing drugs** Additive anaemia, neutropenia and thrombocytopenia. **CYP3A4 inhibitors and inducers** Less relevant than for other PARP inhibitors, because niraparib is cleared mainly by carboxylesterases. ## What is monitored - Complete blood count, especially platelets - Blood pressure and heart rate regularly - Neurological symptoms (headache, confusion, vision) ## Administration and safety - Oral; swallowed whole, never split, crushed, chewed or opened. - Can be taken at bedtime to reduce nausea. - If the patient vomits after a dose, the dose is not repeated; the next one is taken at the usual time. ## Pregnancy and breastfeeding Avoid in pregnancy. Can harm the fetus: a pregnancy test is done before starting, effective contraception is used during treatment and for a time afterwards (by women and by men with partners who could conceive), and breastfeeding is avoided. ## Nursing care - Review blood counts before and during treatment; teach to report pallor, fatigue, bruising, bleeding or fever. - Measure blood pressure and pulse at each visit and teach home checks if ordered. - Teach to report severe headache, confusion or vision changes at once. - Confirm a negative pregnancy test before the first dose and teach contraception during treatment and afterwards. ## Pharmacokinetics **Absorption** Oral capsules, once daily, with or without food; at bedtime if it causes nausea. **Metabolism** Inactivated mainly by carboxylesterases, not mainly by CYP enzymes. **Half-life** About 36 hours. ## Memory aid «NIRAparib raises the pressure»: the PARP inhibitor that needs a blood-pressure cuff, and an eye on the platelets. ## Test yourself Think of the answer, then tap the question to see it. ## Why does niraparib raise blood pressure? It also inhibits the dopamine, noradrenaline and serotonin transporters. ## How is niraparib mainly inactivated? By carboxylesterases, not mainly by CYP enzymes. ## Which neurological syndrome is a warning for niraparib? Posterior reversible encephalopathy syndrome (PRES). [Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/niraparib/) [More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology) ## What the labels mean **High alert** An error with this medicine can cause serious harm: double checks and protocols are used. **Pregnancy: avoid** Avoid in pregnancy. Can harm the fetus: a pregnancy test is done before starting, effective contraception is used during treatment and for a time afterwards (by women and by men… ## Connections ## Related drugs 3 - [Olaparib](https://durgical.com/en/pharmacology/olaparib/) - [Rucaparib](https://durgical.com/en/pharmacology/rucaparib/) - [Talazoparib](https://durgical.com/en/pharmacology/talazoparib/) ## Related conditions 1 - [Ovarian cancer](https://durgical.com/en/conditions/ovarian-cancer/) [← Back to the class: PARP inhibitors](https://durgical.com/en/pharmacology/classes/parp-inhibitors/) Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given. Sources: [Niraparib: MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a617007.html) (MedlinePlus (U.S. National Library of Medicine), 2020); [Niraparib Tosylate Monohydrate - NCI](https://www.cancer.gov/about-cancer/treatment/drugs/niraparibtosylatemonohydrate) (National Cancer Institute, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L01XK02) (WHO Collaborating Centre for Drug Statistics Methodology, 2026). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/pharmacology/niraparib/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/niraparib/