Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Herbal dietary supplement alters metabolism of chemotherapy drug

21.08.2002


Researchers in the Netherlands have found that the herbal dietary supplement St. John’s wort interferes with the metabolism--and potentially the effectiveness of--the chemotherapy drug irinotecan. Their findings appear in the August 21 issue of the Journal of the National Cancer Institute.



St. John’s wort (Hypericum perforatum L.) is widely used to treat mild to moderate forms of depression. Past studies have suggested that the compound increases levels of CYP3A4, an enzyme involved in drug metabolism. The enzyme inactivates the colorectal cancer chemotherapy drug irinotecan.

To examine the interaction between St. John’s wort’s and irinotecan, Ron H. J. Mathijssen, M.D., and Alex Sparreboom, Ph.D., of the Department of Medical Oncology at the Erasmus MC-Daniel den Hoed Cancer Center, and their colleagues treated five patients with irinotecan alone or in combination with St. John’s wort.


At the end of the study, blood levels of SN-38 (the active metabolite of irinotecan) were 42% lower in patients receiving irinotecan and St. John’s wort than when the patients received irinotecan alone. Detoxification of the drug to other known metabolites also decreased with St. John’s wort.

"Our findings suggest that irinotecan metabolism and toxicity are altered by [St. John’s wort] and that the two agents cannot be given safely in combination without compromising overall antitumor activity," the authors write.

They note that their results may have implications for other anticancer drugs metabolized by CYP3A4, such as the taxanes (paclitaxel). Combining these drugs with St. John’s wort may make it necessary to increase drug dosage to achieve the optimal pharmacologic effect. "Until specific dosing guidelines are available, it is strongly recommended that patients receiving chemotherapeutic treatments with such agents refrain from taking [St. John’s wort," they conclude.

In a related editorial, Patrick J. Mansky, M.D., and Stephen E. Straus, M.D., of the National Center for Complementary and Alternative Medicine at the National Institutes of Health, point out that cancer patients are among the most likely to seek complementary and alternative medical remedies to reduce the side effects of treatments. They say that, in addition to St. John’s wort, a number of herbal remedies have been identified that affect synthetic drug metabolism and, potentially, drug efficacy.

The National Institutes of Health is funding studies of complementary and alternative medicine practices in cancer patients. While waiting for these results, "it would be prudent for patients and their oncologists to appreciate that, no matter how beneficial some approaches may appear to be, they are not all safe," the editorialists conclude.


Contact: David Drexhage, Erasmus MC-Daniel den Hoed Cancer Center, +31 10 463 5525, d.a.drexhage@azr.nl (8:30 a.m. to 5:30 p.m. GMT)

Editorial: NCCAM press office, (301) 451-8876

Mathijssen R, Verweij J, Bruijn P, Loos W, Sparreboom A. Effects of St. John’s wort on irinotecan metabolism. J Natl Cancer Inst 2002;94:1247–9.

Editorial: Mansky P, Straus S. St John’s Wort: more implications for cancer patients. J Natl Cancer Inst 2002;94:1187–8.

Attribution to the Journal of the National Cancer Institute is requested in all news coverage.

Linda Wang | EurekAlert!
Further information:
http://jncicancerspectrum.oupjournals.org/

More articles from Health and Medicine:

nachricht Candidate Ebola vaccine still effective when highly diluted, macaque study finds
21.10.2019 | NIH/National Institute of Allergy and Infectious Diseases

nachricht Autism spectrum disorder risk linked to insufficient placental steroid
21.10.2019 | Children's National Hospital

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers watch quantum knots untie

After first reporting the existence of quantum knots, Aalto University & Amherst College researchers now report how the knots behave

A quantum gas can be tied into knots using magnetic fields. Our researchers were the first to produce these knots as part of a collaboration between Aalto...

Im Focus: A cavity leads to a strong interaction between light and matter

Researchers have succeeded in creating an efficient quantum-mechanical light-matter interface using a microscopic cavity. Within this cavity, a single photon is emitted and absorbed up to 10 times by an artificial atom. This opens up new prospects for quantum technology, report physicists at the University of Basel and Ruhr-University Bochum in the journal Nature.

Quantum physics describes photons as light particles. Achieving an interaction between a single photon and a single atom is a huge challenge due to the tiny...

Im Focus: Solving the mystery of quantum light in thin layers

A very special kind of light is emitted by tungsten diselenide layers. The reason for this has been unclear. Now an explanation has been found at TU Wien (Vienna)

It is an exotic phenomenon that nobody was able to explain for years: when energy is supplied to a thin layer of the material tungsten diselenide, it begins to...

Im Focus: An ultrafast glimpse of the photochemistry of the atmosphere

Researchers at Ludwig-Maximilians-Universitaet (LMU) in Munich have explored the initial consequences of the interaction of light with molecules on the surface of nanoscopic aerosols.

The nanocosmos is constantly in motion. All natural processes are ultimately determined by the interplay between radiation and matter. Light strikes particles...

Im Focus: Shaping nanoparticles for improved quantum information technology

Particles that are mere nanometers in size are at the forefront of scientific research today. They come in many different shapes: rods, spheres, cubes, vesicles, S-shaped worms and even donut-like rings. What makes them worthy of scientific study is that, being so tiny, they exhibit quantum mechanical properties not possible with larger objects.

Researchers at the Center for Nanoscale Materials (CNM), a U.S. Department of Energy (DOE) Office of Science User Facility located at DOE's Argonne National...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Symposium on Functional Materials for Electrolysis, Fuel Cells and Metal-Air Batteries

02.10.2019 | Event News

NEXUS 2020: Relationships Between Architecture and Mathematics

02.10.2019 | Event News

Optical Technologies: International Symposium „Future Optics“ in Hannover

19.09.2019 | Event News

 
Latest News

Composite metal foam outperforms aluminum for use in aircraft wings

23.10.2019 | Materials Sciences

Researchers watch quantum knots untie

23.10.2019 | Physics and Astronomy

A technology to transform 2D planes into 3D soft and flexible structures

23.10.2019 | Medical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>