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 NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures
17.11.2017 | National Institute of Standards and Technology (NIST)

nachricht High speed video recording precisely measures blood cell velocity
15.11.2017 | ITMO University

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: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>