Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Study identifies substances in grapefruit juice that interact dangerously with some drugs

10.05.2006


New research from the University of North Carolina at Chapel Hill has identified and established the substance in grapefruit juice that causes potentially dangerous interactions with certain medications.



For almost a decade, people have been told by their doctors and pharmacists to avoid grapefruit juice if they are being treated with certain medications, including some drugs that control blood pressure or lower cholesterol. Studies have shown that grapefruit juice can cause more of these drugs to enter the blood stream, resulting in undesirable and even dangerous side effects.

The drugs affected by grapefruit juice usually have some difficulty entering the body after they are consumed because an intestinal enzyme, CYP3A, partially destroys them as they are absorbed. Grapefruit juice, but not other commonly consumed fruit juices, inhibits this enzyme, allowing more of these drugs to enter the body.


It was originally assumed that the ingredients responsible for drug interactions were the flavonoids that give grapefruit juice its bitter taste.

The new study shows that a group of chemicals called furanocoumarins are the likely culprit.

"This is the best evidence to date that furanocoumarins are the active ingredients in grapefruit juice that cause the interaction with medications," said Dr. Paul Watkins, the Dr. Verne S. Caviness distinguished professor of medicine and director of UNC’s General Clinical Research Center (GCRC). Watkins led the study team.

A report of the new findings appears in the May issue of the American Journal of Clinical Nutrition.

To determine whether furanocoumarins are responsible for grapefruit juice-drug interactions, Watkins worked with scientists at the Florida Department of Citrus to selectively remove only the furanocoumarins from the juice. He and his collaborators then studied the effect of the whole juice versus furanocoumarin-free juice on the ability to affect absorption of felodipine, an anti-hypertension drug known to interact with grapefruit juice "And we found that removing the furanocoumarins from grapefruit juice entirely got rid of this interaction," Watkins said.

In this randomized study, 18 healthy volunteers took 10 milligrams of felodipine with each of three juices: orange juice, regular grapefruit juice, and grapefruit juice devoid of furanocoumarins. Blood was collected over 24 hours to measure felodipine blood levels. One week elapsed between each felodipine-juice "treatment."

The study found that in contrast to whole grapefruit juice, the furanocoumarin-free grapefruit juice behaved like orange juice and did not cause an interaction with felodipine.

Watkins notes that there are several implications of this work.

"First, it should now be possible to market the furanocoumarin-free grapefruit juice to patients who would otherwise need to avoid grapefruit. In addition, it should be possible to screen new foods for the potential for drug interactions by determining whether they contain furanocoumarins.

"Finally, it may be possible to add furanocoumarins to formulations of certain drugs that tend to be poorly or erratically absorbed to improve their oral delivery."

Leslie H. Lang | EurekAlert!
Further information:
http://www.med.unc.edu

More articles from Studies and Analyses:

nachricht Amputees can learn to control a robotic arm with their minds
28.11.2017 | University of Chicago Medical Center

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

A whole-body approach to understanding chemosensory cells

13.12.2017 | Health and Medicine

Water without windows: Capturing water vapor inside an electron microscope

13.12.2017 | Physics and Astronomy

Cellular Self-Digestion Process Triggers Autoimmune Disease

13.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>