http://www.arthritis.org/info-for-celebrex-users.php
By Denise Lynn Mann
The
lone COX-2 drug celecoxib (Celebrex) has been linked to a new heart
woe: irregular heart beats, or arrhythmia. To learn what this means for
the millions of people with arthritis who regularly take celecoxib to
treat their joint pain and inflammation, Arthritis Today
spoke with lead study author Satpal Singh, PhD, an associate professor
of pharmacology and toxicology at the University of Buffalo School of
Medicine and Biomedical Sciences in New York:
How might taking celecoxib cause an arrhythmia?
“Celecoxib
inhibited the normal passage of potassium ions into and out of heart
cells by blocking potassium channels, which interrupted the heart’s
rhythm. Potassium channels allow influx and outflux of potassium ions
to maintain the proper amount so the heart can beat correctly. Too much
or too little potassium causes irregularities: The heart may beat too
slow or too fast. Severe irregularities may be life threatening.”
How did you make this discovery?
“It
was basically initiated by the Vioxx research. Because the COX-2 drugs
seemed to have an effect on the heart, we attempted to see if these
drugs affected the hearts of fruit flies. If they did, we could use it
as a model system for further studies. It did have an effect on the
fruit flies’ hearts, but not in the way that we thought it would.”
What do you mean?
“The
effect was entirely different than what was seen in the Vioxx studies.
In those studies, the COX-2 drugs increased risk of heart attack and
stroke by making people more prone to blood clots. Our finding on
arrhythmias has nothing to do with that.”
Did you use high doses of the drug to see this effect in your experiments?
“No. We used low concentrations of the drug that correspond to a standard prescription.”
Your study was not conducted in humans. How can you be sure that this same phenomenon could theoretically occur in people?
“We
can't be. It would be premature to make a claim that it could. We did
see this effect in a study of human cells, so we can say that in the
cell line that we studied, the human potassium channels are also
affected. This gives us a strong reason to explore further whether it
affects humans.”
What should people with arthritis who take celecoxib do now, if anything?
“At
this stage, it is premature to be worried about arrhythmias if you take
celecoxib. Talk to your doctor if you have any concerns.”
Source: Journal of Biological Chemistry, Vol. 283, No. 3