Last year, Pfizer's Viagra sales totaled $1.7 billion, including $800 million in the United States.

In 2000, Viagra sales accounted for 92 percent of the global market for prescribed erectile dysfunction pills.

In a small way, it could help buttress Viagra sales as new competitors eat into the market for impotence medications.

As the only pill for impotence in a sexually active culture, Viagra sales could soar to several billion dollars annually in a year or two, securities analysts said yesterday.

Globally, Pfizer earned $1.66 billion from Viagra sales in 2006.

Pfizer had about $900 million of Viagra sales in the United States last year, Dr. Yaffe said.

Viagra sales should continue to grow, he said, but at a slower rate.

Worldwide sales topped $1 billion in 1999, and some Wall Street analysts predicted that Viagra sales would reach several billion dollars annually.

Mr. Sweig said that less than half of the Viagra sales of $981 million in its first 12 months were covered by insurance.

The Wall Street Journal reports that Viagra sales have er, come down.