Although Mevacor, a Merck cholesterol-lowering drug lost market share, sales were up 8 percent in the quarter, to $415 million, and reached $1.35 billion for the year.

And a new Merck drug to counteract niacin-induced flushing is being tested in Britain.

He estimated the nine Merck drugs would have total Canadian sales this year of about $201 million.

There are numerous examples of Merck's having published trial results that were inconclusive or even unfavorable to the Merck drug.

The Merck drug is also single dose.

He had been a vocal critic of Vioxx, a Merck drug, which was withdrawn from the market.

Thirteen percent of Medco sales are from Merck drugs, up from 10 percent two years ago.

If sales of Merck drugs falter, they said, the rebates would shrink, sharply cutting Medco's profits.

Mr. Bukoll also noted Medco's commitments to promote Merck drugs, even after becoming independent one day.

The patents on several popular Merck drugs expired in 2000 and 2001, opening them to generic competition.