Featured Research

from universities, journals, and other organizations

Ibuprofen Blocks Aspirin’s Ability To Protect Against Heart Attacks; Common Arthritis Drugs Can Stop Aspirin From Thinning The Blood

Date:
December 20, 2001
Source:
University Of Pennsylvania Medical Center
Summary:
The ibuprofen that you take to ease arthritis pain can counteract the aspirin that you take to protect your heart, according to researchers at the University of Pennsylvania School of Medicine. The researchers studied how aspirin, taken to prevent second heart attacks, interacts with nonsteroidal anti-inflammatory drugs (NSAIDs), a group of drugs that includes ibuprofen, commonly taken to treat rheumatoid arthritis.

(Philadelphia, PA) – The ibuprofen that you take to ease arthritis pain can counteract the aspirin that you take to protect your heart, according to researchers at the University of Pennsylvania School of Medicine. The researchers studied how aspirin, taken to prevent second heart attacks, interacts with nonsteroidal anti-inflammatory drugs (NSAIDs), a group of drugs that includes ibuprofen, commonly taken to treat rheumatoid arthritis. Their findings are published in the December 20th issue of the New England Journal of Medicine.

“Our findings have shown that multiple daily doses of ibuprofen can undermine the cardioprotective effects of a daily aspirin regimen,” said Garret A. FitzGerald, MD, Robinette Professor of Cardiovascular Medicine, chair of the Penn Department of Pharmacology, and director of the Penn Center for Experimental Therapeutics. “NSAIDs and aspirin are two of the most frequently consumed drugs in North America and, since people commonly take both drugs daily, it is important to see how they could interact.” Much of their concern rests in the fact that aspirin and NSAIDs both inhibit two different versions of the same enzyme, a protein called cyclooxygenase (COX). One variant of the enzyme, COX-1, found in platelets, is essential in creating the molecules that allow platelets to clot blood. The other variant, COX-2, produces the molecules responsible for the pain and inflammation symptomatic of arthritis.

Aspirin will bind to the COX-1 enzyme irreversibly, thereby permanently putting the enzyme – and the platelet – out of commission. Such a sustained effect on platelets is key to the ability of aspirin to prevent heart attack and stroke. NSAIDs, however, bind less strongly to a different part of the enzyme, and only impair platelets for a short time. There is no evidence that NSAIDs prevent heart attack or stroke, but their effects on COX-2 help relieve pain and swelling.

“Since both NSAIDs and aspirin both bind near the reactive site deep within the COX-1 enzyme, we thought that NSAIDs might physically block aspirin from reaching its target,” explained Muredach Reilly, MD, a Penn cardiologist and co-author of the study. “It would not do you a lot of good to take one medication only to have another wipe out its effects.”

In particular, the researchers studied the over the counter NSAIDs ibuprofen (e.g. Advil®), diclofenac (Voltaren®) and acetaminophen (e.g. Tylenol®), as well as the prescription NSAID refocoxib (e.g. Vioxx®), which is part of a class of newer, COX-2 specific, NSAIDs. To determine how the drugs might interact, the researchers first studied how the order of dosing might influence the effects of combinations of aspirin with the various NSAIDs on the number of working platelets in volunteers. As they had guessed, taking ibuprofen before aspirin prevented aspirin’s effects on platelet COX-1. If they took aspirin 2 hours before the ibuprofen, however, there was no problem.

They then repeated the study, giving ibuprofen three times a day – the way people would generally take the drug for persistent pain or inflammation. This time they loaded the die against the interaction by giving the aspirin two hours before the morning dose of ibuprofen each day. To their surprise, there was still enough ibuprofen around from the prior evening’s dose to cause the aspirin-blocking interaction. “We know that aspirin works to protect the heart by acting as a blood thinner, that is, it prevents clotting by inactivating the enzyme that makes platelets stick together,” said FitzGerald. “This study tells us that ibuprofen can prevent this from happening by denying aspirin access to the enzyme’s active site.” As expected, the researchers failed to see an interaction with rofecoxib, an important point of distinction for patients on aspirin who are making a choice amongst NSAIDs. As a member of the newer COX-2 specific drugs, rofecoxib does not bind to COX-1 in platelets. Perhaps more surprisingly, the interaction was also absent from combinations of aspirin with diclofenac, an older NSAID. The interaction occurs in a narrow channel deep within the COX-1 molecule. “There is some evidence that diclofenac binds within the enzyme somewhat differently than does ibuprofen, but the failure to interact may also reflect its preference for COX-2, its turnover, or some other factor as yet to be identified,” said FitzGerald. The researchers also failed to see an interaction with 1000mg of acetaminophen. However, they did find out that at this dose acetaminophen is a weak NSAID. It remains to be seen if higher doses of acetaminophen can exert a full NSAID effect and whether they might effect aspirin like ibuprofen does.

“This study tells us that patients who take ibuprofen, the most common NSAID consumed in North America, are susceptible to an interaction that would undermine the cardioprotective action of low dose aspirin,” said FitzGerald. “Patients taking aspirin to protect against heart attack should seek the advice of their doctors before commencing additional treatments for pain or inflammation.”

This study was funded, in part, by the National Institutes of Health and the Bayer Corporation.


Story Source:

The above story is based on materials provided by University Of Pennsylvania Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

University Of Pennsylvania Medical Center. "Ibuprofen Blocks Aspirin’s Ability To Protect Against Heart Attacks; Common Arthritis Drugs Can Stop Aspirin From Thinning The Blood." ScienceDaily. ScienceDaily, 20 December 2001. <www.sciencedaily.com/releases/2001/12/011220081520.htm>.
University Of Pennsylvania Medical Center. (2001, December 20). Ibuprofen Blocks Aspirin’s Ability To Protect Against Heart Attacks; Common Arthritis Drugs Can Stop Aspirin From Thinning The Blood. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2001/12/011220081520.htm
University Of Pennsylvania Medical Center. "Ibuprofen Blocks Aspirin’s Ability To Protect Against Heart Attacks; Common Arthritis Drugs Can Stop Aspirin From Thinning The Blood." ScienceDaily. www.sciencedaily.com/releases/2001/12/011220081520.htm (accessed July 25, 2014).

Share This




More Health & Medicine News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

Beatings and Addiction: Pakistan Drug 'clinic' Tortures Patients

AFP (July 24, 2014) — A so-called drugs rehab 'clinic' is closed down in Pakistan after police find scores of ‘patients’ chained up alleging serial abuse. Duration 03:05 Video provided by AFP
Powered by NewsLook.com
Too Few Teens Receiving HPV Vaccination, CDC Says

Too Few Teens Receiving HPV Vaccination, CDC Says

Newsy (July 24, 2014) — The Centers for Disease Control and Prevention is blaming doctors for the low number of children being vaccinated for HPV. Video provided by Newsy
Powered by NewsLook.com
New Painkiller Designed To Discourage Abuse: Will It Work?

New Painkiller Designed To Discourage Abuse: Will It Work?

Newsy (July 24, 2014) — The FDA approved Targiniq ER on Wednesday, a painkiller designed to keep users from abusing it. Like any new medication, however, it has doubters. Video provided by Newsy
Powered by NewsLook.com
Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Doctor At Forefront Of Fighting Ebola Outbreak Gets Ebola

Newsy (July 24, 2014) — Sheik Umar Khan has treated many of the people infected in the Ebola outbreak, and now he's become one of them. 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