Forest Laboratories ( FRX) said Tuesday that it expects its third-quarter profit to exceed Wall Street estimates by 15%. Making its announcement after markets had closed, Forest said it expected earnings per share to top the consensus estimate of 59 cents because of strong sales volume, especially for its antidepressant Lexapro. The company will announce formal financial results for the quarter ended Dec. 31, on Jan 18. For the same period last year, Forest earned 60 cents a share. Forest's stock dropped $1.28, or 2.9%, to $42.90 in regular trading. After hours, shares gained 33 cents. The company expects third-quarter sales of $795 million, including $427 million for Lexapro. The antidepressant Celexa produced sales of approximately $130 million as generic competition began to take its toll. Sales of Namenda, for treating moderate to severe Alzheimer's disease, were approximately $100 million.