St. John's Wort - Zejula (Niraparib Tosylate) Interaction
Herbal: St. John's Wort
Also Known As: Hypericum perforatum, Amber Touch-and-Heal, Barbe de Saint-Jean, Chasse-diable, Demon Chaser, Fuga Daemonum, Hardhay, Herbe Aux Mille Vertus, Hypereikon, Hyperici Herba, Hypericum, Millepertuis, Perforate St. John's Wort, Racecourse Weed, Rosin Rose, Saynt Johannes Wort
Drug: Niraparib Tosylate
Brand names:
Zejula
Medical Content Editor Dr. Brian Staiger, PharmD
Last updated
May 04, 2025
Interaction Details
Niraparib Tosylate is classified as belonging to the following category: P-Glycoprotein Substrates
St. John's wort decreases the levels and clinical effects of P-glycoprotein substrates.
St. John's wort induces P-glycoprotein. P-glycoprotein is a carrier mechanism responsible for transporting drugs and other substances across cell membranes. When P-glycoprotein is induced in the gastrointestinal (GI) tract, it can prevent the absorption of some medications. In addition, induction of p-glycoprotein can decrease entry of drugs into the central nervous system (CNS) and decrease access to other sites of action.
Interaction Rating
Likelihood of Occurrence
ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
References
- Johne A, Brockmoller J, Bauer S, et al. Pharmacokinetic interaction of digoxin with an herbal extract from St John's wort (Hypericum perforatum). Clin Pharmacol Ther 1999;66:338-45.
- Durr D, Stieger B, Kullak-Ublick GA, et al. St. John's Wort induces intestinal P-glycoprotein/MDR1 and intestinal and hepatic CYP3A4. Clin Pharmacol Ther 2000;68:598-604.
- Hennessy M, Kelleher D, Spiers JP, et al. St Johns wort increases expression of P-glycoprotein: implications for drug interactions. Br J Clin Pharmacol 2002;53:75-82.
- Kim RB. Drugs as P-glycoprotein substrates, inhibitors, and inducers. Drug Metab Rev 2002;34:47-54.
St. John's Wort Overview
St. John's wort (Hypericum perforatum) is a plant native to Europe and is known for its medicinal properties. St. John's wort has been used to treat a variety of conditions, including depression, anxiety, and sleep disorders. It is one of the most extensively used and researched natural medicines in the world, and is thought to work similarly to certain conventional antidepressants by increasing the levels of serotonin in the brain.
Niraparib Tosylate Overview
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Niraparib is used to help maintain the response of certain types of ovarian (female reproductive organs where eggs are formed), fallopian tube (tube that transports eggs released by the ovaries to the uterus), and peritoneal (layer of tissue that lines the stomach) cancer in people who have completely responded or partially responded to other chemotherapy medication(s). It is also used to treat certain types of ovarian, fallopian tube, or peritoneal cancer when the cancer has gotten worse after 3 or more chemotherapy treatments. Niraparib is in a class of medications called poly (ADP-ribose) polymerase (PARP) inhibitors. It works by killing cancer cells.
St. John's Wort - More Interactions
St. John's Wort interacts with 1115 drugs
Interaction Rating Key
These severity listings are for informational use only. Never start, stop or otherwise change your therapy before speaking with your provider.
| Major | The combined use of these agents is strongly discouraged as serious side effects or other negative outcomes could occur. |
| Moderate | Use cautiously under the care of a healthcare professional or avoid this combination. A significant interaction or negative outcome could occur. |
| Minor | Be aware that there is a chance of an interaction. Watch for warning signs of a potential interaction. |
| Unknown | No interactions have been reported or no interaction data is currently available. |
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Parts of this content are provided by the Therapeutic Research Center, LLC.
DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.
© 2021 Therapeutic Research Center, LLC
Drug descriptions are provided by MedlinePlus.
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Dr. Brian Staiger, PharmD
In addition to being a clinical pharmacist specializing in pharmacotherapy, Dr. Brian Staiger is a registered herbalist through the American Herbalist Guild. He has combined his passion for pharmacy practice with the study of medical ethnobotany to improve patient care. Feel free to reach out about any of your herbal or medication questions!
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