Stopping Plavix may carry early clotting risk

By Julie Steenhuysen

CHICAGO (Reuters) - Patients given the blood-clot preventer Plavix after a heart attack or after receiving a stent have a far higher risk of heart attack or death in the three months after they stop taking the drug, U.S. researchers said on Tuesday.

They found a cluster of heart problems occurring within 90 days of stopping the drug in people whose heart disease was treated either with drugs or a stent to prop open their arteries.

"It was almost a twofold increased risk in that initial period compared to later follow-up periods," said Dr. P. Michael Ho of the Denver VA Medical Center, whose study appears in the Journal of the American Medical Association.

People who have acute coronary syndrome -- an umbrella term for heart problems caused by reduced blood flow to the heart -- routinely get a prescription for Plavix, one of the world's best-selling medicines sold by Bristol-Myers Squibb Co and Sanofi-Aventis.

Known generically as clopidogrel, Plavix prevents blood clots that can cause heart attacks and strokes. It works by preventing disc-shaped elements of the blood called platelets from sticking together.

Some studies have suggested there may be a "rebound effect" of extra blood clots in the period right after people have stopped taking other anti-platelet drugs, including aspirin. Ho and colleagues wanted to see if this might be happening in patients taking Plavix.

His team studied 3,137 veterans with acute coronary syndrome who had been discharged with a prescription for Plavix after they had been treated either with a stent to open a blocked artery or with a combination of medicines designed to manage their heart disease.

They tracked the number of heart attacks and deaths in the three months, six months and nine months after people stopped taking Plavix.