"On the other hand, if it's not excessive bleeding and there are other options to explore, the safety issue may hold you back from doing this."

The treatment did not increase the risk of unwanted clots in veins, regardless of age, the researchers found. It increased the risk of stroke, but not enough to be statistically significant.

Dr. Louis Aledort of the Mount Sinai School of Medicine in New York said in a commentary that 4 percent of the NovoSeven used at his hospital is for non-approved therapy. "At other centers, the rate of off-label use may be even higher," Aledort said.

Levi said hospitals that are quick to give the drug may now want to reconsider that practice.