Featured Research

from universities, journals, and other organizations

A Note Of Caution: Be Careful When Mixing Grapefruit Juice With Rxs

Date:
April 8, 1999
Source:
American Association Of Pharmaceutical Scientists
Summary:
Drinking a glass of grapefruit juice with medications has long been known to help with the body's absorption of certain drugs. However, scientists at the University of California at San Francisco (UCSF) have now found that grapefruit juice may actually have a negative impact on the body's absorption of many widely-prescribed medications.

New Study Finds Grapefruit Juice Could Decrease the Absorption of Many Drugs

Alexandria, VA -- Drinking a glass of grapefruit juice with medications has long been known to help with the body's absorption of certain drugs. However, scientists at the University of California at San Francisco (UCSF) have now found that grapefruit juice may actually have a negative impact on the body's absorption of many widely-prescribed medications.

Grapefruit juice is known to improve the oral absorption of several important medications on the market by decreasing levels of an intestinal enzyme, known as CYP3A4, that would otherwise breakdown drug molecules before they reach the blood stream. These drugs include antihypertensive calcium channel blockers (i.e., felodipine, Plendil and HIV-protease inhibitors (i.e., saquinavir, Invirase).

In a study* published in the April 1999 issue of Pharmaceutical Research, an American Association of Pharmaceutical Scientists (AAPS) publication, Dr. Andrea Soldner and other scientists at UCSF demonstrate that grapefruit juice can actually inhibit the body's absorption of certain drugs including: Vinblastine (for combating cancer) Cyclosporine (for supressing organ rejection following transplant)Losartan (for controlling high blood pressure)Digoxin (for treating congestive heart failure) Fexofenadine (for alleviating allergy symptoms)

This inhibition occurs because an unknown substance in grapefruit juice activates one of the body's naturally-produced drug efflux mechanisms, known as P-glycoprotein, located in the intestinal tract. When grapefruit juice interacts with P-glycoprotein, the result is an increased likelihood that certain drugs will be stopped from entering the bloodstream.

These findings help to clarify some major discrepancies we've noticed in the impact of grapefruit juice on various types of medications," said Dr. Leslie Benet, founder of the American Association of Pharmaceutical Scientists, professor of Biopharmaceutical Sciences at UCSF and director of the study. Patients already taking grapefruit juice with their medications can continue to do so. However, for certain drugs we studied, such as immunosuppressives and HIV protease inhibitors, patients may get a further increase in absorption by taking their drugs a couple of hours after a glass of grapefruit juice.

According to Dr. Benet, Patients who have not previously taken their drugs with grapefruit juice should be very cautious in doing so, since we now recognize, depending on the drug, that grapefruit juice may either increase or decrease levels of drug in the blood, leading to potential concerns for toxicity or lack of efficacy.

###AAPS is a professional, scientific society of more than 9,000 members employed in academia, industry, government and other research institutes worldwide. Founded in 1986, the goal of AAPS is to improve human health through the development of better pharmaceuticals. For more information about AAPS, visit our Web site at http://www.aaps.org.

*The results of the in vitro experiments are only preliminary and have yet to be proven in animal and human studies.


Story Source:

The above story is based on materials provided by American Association Of Pharmaceutical Scientists. Note: Materials may be edited for content and length.


Cite This Page:

American Association Of Pharmaceutical Scientists. "A Note Of Caution: Be Careful When Mixing Grapefruit Juice With Rxs." ScienceDaily. ScienceDaily, 8 April 1999. <www.sciencedaily.com/releases/1999/04/990408070156.htm>.
American Association Of Pharmaceutical Scientists. (1999, April 8). A Note Of Caution: Be Careful When Mixing Grapefruit Juice With Rxs. ScienceDaily. Retrieved August 23, 2014 from www.sciencedaily.com/releases/1999/04/990408070156.htm
American Association Of Pharmaceutical Scientists. "A Note Of Caution: Be Careful When Mixing Grapefruit Juice With Rxs." ScienceDaily. www.sciencedaily.com/releases/1999/04/990408070156.htm (accessed August 23, 2014).

Share This




More Health & Medicine News

Saturday, August 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Drug Used To Treat 'Ebola's Cousin' Shows Promise

Newsy (Aug. 21, 2014) An experimental drug used to treat Marburg virus in rhesus monkeys could give new insight into a similar treatment for Ebola. Video provided by Newsy
Powered by NewsLook.com
Two US Ebola Patients Leave Hospital Free of the Disease

Two US Ebola Patients Leave Hospital Free of the Disease

AFP (Aug. 21, 2014) Two American missionaries who were sickened with Ebola while working in Liberia and were treated with an experimental drug are doing better and have left the hospital, doctors say on August 21, 2014. Duration: 01:05 Video provided by AFP
Powered by NewsLook.com
Cadavers, a Teen, and a Medical School Dream

Cadavers, a Teen, and a Medical School Dream

AP (Aug. 21, 2014) Contains graphic content. He's only 17. But Johntrell Bowles has wanted to be a doctor from a young age, despite the odds against him. He was recently the youngest participant in a cadaver program at the Indiana University NW medical school. (Aug. 21) Video provided by AP
Powered by NewsLook.com
American Ebola Patients Released: What Cured Them?

American Ebola Patients Released: What Cured Them?

Newsy (Aug. 21, 2014) It's unclear whether the American Ebola patients' recoveries can be attributed to an experimental drug or early detection and good medical care. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins