Celebrex, a popular arthritis drug that blocks pain by inhibiting an enzyme known as COX-2, has been shown in laboratory studies to induce arrhythmia, or irregular beating of the heart, via a novel pathway unrelated to its COX-2 inhibition.
University at Buffalo researchers discovered this unexpected finding while conducting basic research on potassium channels.
They found that low concentrations of the drug, corresponding to a standard prescription, reduced the heart rate and induced pronounced arrhythmia in fruit flies and the heart cells of rats.
The drug inhibited the normal passage of potassium ions into and out of heart cells through pores in the cell membrane known as delayed rectifier potassium channels, the study showed.
Aware that COX-2 inhibitors had been shown to produce cardiovascular side effects, the researchers first tested whether Celebrex would affect the heart in fruit flies, a good animal system for studies on heart in other species, including humans.
The researchers now are examining the underlying molecular mechanisms responsible for the drug’s action and its effect on other ion channels that play a prominent role in setting the rhythm of the heart.