Pharmaceutical companies were down across the board on Friday following bleak news coming out of the sector. Merck ( MRK) warned of an earnings shortfall for the second quarter and full year, and its shares lost 7.4% to $69 in recent New York Stock Exchange trading. Also this morning, Schering-Plough ( SGP) was down 6.5% to $37.93 after the company said the Food and Drug Administration has found that it still isn't in compliance with good manufacturing practices. The regulators first found problems with the company's operations in February. Additionally, Wyeth-Ayerst Laboratories, the pharmaceuticals unit of American Home Products ( AHP), said it has received a not-approvable letter from the FDA for a treatment for acute long-bone fractures. The agency's letter focused on the design of the clinical study and the interpretation of the clinical data. Shares of AHP were off 2.2% to $60.83 in afternoon market activity. Others in the sector were also moving downward. GlaxoSmithKline ( GSK) was off 0.6% to $56.55, and Pfizer ( PFE) lost 4.2% to $43. AstraZeneca ( AZN) dropped 1.4% to $49.20, and Bristol-Myers Squibb ( BMY) fell 1.6% to $54.45. Novartis ( NVS) was off 4.7% to $34.98. Aventis ( AVE) slipped 0.4% to $78.32, while Pharmacia ( PHA) slid 5% to $48.93. Johnson & Johnson ( JNJ) lost 2.5% to $51.72.