Featured Research

from universities, journals, and other organizations

Painkiller undermines aspirin's anti-clotting action

Date:
December 17, 2009
Source:
University of Michigan Health System
Summary:
Millions of Americans take Celebrex for arthritis or other pain. Many, if they are middle-aged or older, also take a low-dose aspirin tablet daily to reduce the risk of heart attack and stroke. Yet they may be getting little protection, because Celebrex keeps the aspirin from doing its job effectively, a new study suggests.

Millions of Americans take Celebrex for arthritis or other pain. Many, if they are middle-aged or older, also take a low-dose aspirin tablet daily to reduce the risk of heart attack and stroke. Yet they may be getting little protection, because Celebrex keeps the aspirin from doing its job effectively, a new study suggests.

Related Articles


In laboratory studies, University of Michigan researchers found that several coxibs, the drug class to which Celebrex belongs, interfere with aspirin's ability to discourage blood clots, if the aspirin is taken in low doses. Celebrex, also known as celecoxib, is the only coxib currently on the market. The results appear online in the Proceedings of the National Academy of Sciences.

Doctors frequently advise daily low-dose aspirin (81 mg) for patients who have heart conditions, notably a serious form of angina known as unstable angina, or for patients who are at risk of second heart attacks. Aspirin is well-known for its ability to discourage formation of blood clots that can lead to heart attack and stroke. In addition, arthritis patients who take Celebrex regularly are often put on low-dose aspirin because this is thought to counteract Celebrex's own potential clot-promoting effect.

"There are many people who take low-dose aspirin, perhaps as many as half of men over 50. If they are also prescribed Celebrex for arthritis or other pain, our results suggest that the Celebrex will probably interfere with the aspirin's action," says William L. Smith, Ph.D., the study's senior author, Minor J. Coon Professor of Biological Chemistry and chair of the biochemistry department at the U-M Medical School.

"The greatest risk is having people take Celebrex who are taking aspirin for cardiovascular problems that are known to be mitigated by aspirin, including patients with unstable angina or those at risk for a second heart attack," he says. In unstable angina, small clots form in arteries and interfere with blood flow.

Previous studies of healthy subjects found no ill effect on blood clotting when Celebrex was combined with aspirin at higher doses, specifically a daily "regular" aspirin tablet (324 mg), Smith notes.

So it may be that a higher aspirin dose, or spreading out the time between taking low-dose aspirin and Celebrex, will allow aspirin to be effective. Aspirin's undesirable effects on the gastrointestinal tract at higher doses when taken long-term would have to be taken into account.

First, though, the effect seen in the U-M study needs to be replicated in studies of low-dose aspirin and Celebrex in people, perhaps in older patients who have conditions such as rheumatoid arthritis, says Smith. If the effect holds true in people, it will be important to determine if a balance in dose and/or dose regimens can be found so that aspirin and Celebrex can both be effective.

Research details

The researchers used biochemical measurements and X-ray crystallography to discover that celecoxib binds to COX-1, an enzyme that promotes clotting, and slows aspirin's COX-1-blocking action. In animal studies, the researchers found more clumping of platelets -- the initial stage of clotting -- in blood from animals given Celebrex and low-dose aspirin than in animals given only low-dose aspirin.

Background

Celebrex is one member of a class of drugs known as coxibs or COX-2 inhibitors, developed to selectively block the action of pain-causing enzymes while minimizing side effects such as gastrointestinal problems. Celebrex is the most widely prescribed COX-2 inhibitor in the United States.

More than half of older patients taking COX-2 inhibitors long-term were also taking aspirin to protect against heart disease, according to a 2004 study in the Archives of Internal Medicine.

Additional authors: Gilad Rimon, U-M and Ben-Gurion University of the Negev, Israel, first author; Ranjinder S. Sidhua, D. Adam Lauver, Jullia Y. Lee, Narayan P. Sharma, Chong Yuan, Ryan A. Frieler, Raymond C. Trievel and Benedict R. Lucchesi, all at U-M.

Funding: National Institutes of Health, Heart and Stroke Foundation of Canada


Story Source:

The above story is based on materials provided by University of Michigan Health System. Note: Materials may be edited for content and length.


Journal Reference:

  1. Rimon et al. Coxibs interfere with the action of aspirin by binding tightly to one monomer of cyclooxygenase-1. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0909765106

Cite This Page:

University of Michigan Health System. "Painkiller undermines aspirin's anti-clotting action." ScienceDaily. ScienceDaily, 17 December 2009. <www.sciencedaily.com/releases/2009/12/091214173750.htm>.
University of Michigan Health System. (2009, December 17). Painkiller undermines aspirin's anti-clotting action. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2009/12/091214173750.htm
University of Michigan Health System. "Painkiller undermines aspirin's anti-clotting action." ScienceDaily. www.sciencedaily.com/releases/2009/12/091214173750.htm (accessed October 25, 2014).

Share This



More Health & Medicine News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Texas Nurse Nina Pham Cured of Ebola

Texas Nurse Nina Pham Cured of Ebola

AFP (Oct. 25, 2014) — An American nurse who contracted Ebola while caring for a Liberian patient in Texas has been declared free of the virus and will leave the hospital. Duration: 01:01 Video provided by AFP
Powered by NewsLook.com
IKEA Desk Converts From Standing to Sitting With One Button

IKEA Desk Converts From Standing to Sitting With One Button

Buzz60 (Oct. 24, 2014) — IKEA is out with a new convertible desk that can convert from a sitting desk to a standing one with just the push of a button. Jen Markham explains. Video provided by Buzz60
Powered by NewsLook.com
Ebola Protective Suits Being Made in China

Ebola Protective Suits Being Made in China

AFP (Oct. 24, 2014) — A factory in China is busy making Ebola protective suits for healthcare workers and others fighting the spread of the virus. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com
WHO: Millions of Ebola Vaccine Doses by 2015

WHO: Millions of Ebola Vaccine Doses by 2015

AP (Oct. 24, 2014) — The World Health Organization said on Friday that millions of doses of two experimental Ebola vaccines could be ready for use in 2015 and five more experimental vaccines would start being tested in March. (Oct. 24) Video provided by AP
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:

Strange & Offbeat Stories

 

Health & Medicine

Mind & Brain

Living & Well

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