Jury selection began in Houston on Tuesday in the latest high stakes legal battle for Merck & and its first in a federal courtroom.

Merck & Co., with one victory and one loss in Vioxx lawsuits tried in state courts, may win the first federal trial over the painkiller, lawyers said.

A lawyer representing the widow of man who claims that Merck & Co.'s Vioxx caused her husband's death argued that taking the pain reliever for one month was enough to cause the 53-year-old man's heart attack.

A lawyer representing the widow of man who claims that Merck & Co.'s Vioxx caused her husband's death called the link between the pain reliever and heart attacks the company's "dirty little secret."

A nationally known pharmacology expert testified that the prescription painkiller Vioxx can cause blood clots like the one that led to the death of a Florida seafood salesman four years ago.

With the score 1-1 in the high-stakes game of Vioxx pharmaceutical litigation, the tie-breaking trial begins in federal court in Houston.

After state court trials in Texas and New Jersey, the first Vioxx lawsuit in federal court goes to trial in Houston this week, but the issue remains essentially the samewhether short-term use of the once-popular pain reliever causes heart attacks.

The nation's third Vioxx trial and the first in a federal courtroom gets under way in Houston this week, and a verdict would break a current tie in one of the most high-profile consumer legal battles in the past decade.

Vioxx trials, said that Merck should be "excited" about fighting the next battle in federal district court. "Oftentimes state court judges are not listening to them."

The first federal trial over Merck & Co.'s Vioxx painkiller is scheduled to begin next week, but it could take several more trials before the drug maker decides whether to begin settling cases or stand by its vow to fight thousands of lawsuits over many years.