Schering-Plough Corp. said Friday it had received government approval for Clarinex, the successor to the company's best-selling allergy drug Claritin.

The U.S. Food and Drug Administration had previously held up approval of the drug while it investigated quality violations at the company's New Jersey and Puerto Rico factories.

In conjunction with the approval, Schering-Plough said it was currently negotiating a consent decree with the FDA to resolve compliance issues at the factories that could lead to a payment as much as $500 million.

Investors responded to the news by pushing shares up $2.65, or 7 percent, in after-hours trading after finishing the regular session up 24 cents to $36.35 on the New York Stock Exchange.

FDA spokesman Lawrence Bachorik confirmed that the agency did approve Clarinex, but would not comment further.

Claritin is one of Kenilworth, N.J.-based Schering-Plough's best-selling drugs and the world's top-selling antihistamine. It took in $3 billion in sales in 2000 — about one-third of the company's revenue. The drug will go off patent protection later this month.

Clarinex, a once-daily nonsedating antihistamine to treat seasonal allergic rhinitis, will launch in January.

Richard Jay Kogan, Schering-Plough's chairman and chief executive, also said hat earnings per share would be about 7 percent below the comparable 2000 period of 39 cents per share, however, citing the impact of manufacturing issues on product sales. That would be about 36 cents per share and does not include any impact from the potential consent decree.

Analysts surveyed by Thomson Financial/First Call were expecting earnings of 41 cents per share. For the year, Kogan said that earnings would be off 4 percent from last year's $1.64 per share, or about $1.57; analysts had been expecting $1.63 per share.