Shares of Mylan Inc. slid in after-hours trading yesterday after the Cecil generic drug maker posted a first-quarter loss of $443.9 million and cut its earnings forecast through 2010.

The first-quarter loss, which amounted to $1.46 per diluted share, reflected more than $500 million in charges related to Mylan's $6.8 billion October acquisition of Merck Generics. It also reflected $34.7 million in dividends paid on preferred stock issued to finance the deal.

Revenue more than doubled to $1.07 billion. Excluding sales generated by Merck, revenue fell nearly 9 percent.

Mylan said excluding one-time items, it earned 9 cents per diluted share, in line with analysts' consensus estimate of 8 cents per share.

In the year-ago quarter, Mylan reported a loss of $71.3 million, or 31 cents per diluted share, on revenue of $487.3 million.

One-time charges included a $385 million noncash accounting charge related to the possible sale of Mylan's Dey specialty pharmaceutical business that it acquired when it bought Merck Generics, and other accounting charges of $118.1 million related to the acquisition.

"Our global generics business is performing extremely well," Vice Chairman and Chief Executive Officer Robert J. Coury told analysts during a conference call.

Mr. Coury said the company expects to report adjusted earnings per share of 40 cents to 50 cents this year, 90 cents to $1.10 next year, and $1.50 to $1.70 in 2010. That's down from projections issued in October of 70 cents to 90 cents per share in 2008 and $2 to $2.40 in 2010. The decrease anticipates the sale of Dey, expected in the fourth quarter, and reflects higher investment costs, Mr. Coury said.

Mylan also scaled back projected annual savings from synergies with Merck, from $300 million to $275 million by the end of 2010.

The results were announced after the market closed. Mylan finished at $12.46, down 35 cents for the day, and continued falling in after-hours trading. The shares are off 11 percent this year and down from the $22 range before the Merck deal was announced last year.