Shares in Salix Pharmaceuticals (Nasdaq: SLXP) fell 34 cents, or 4.7 percent, Monday after the company said the Food and Drug Administration had requested more information about a proposed new product.

The FDA sent Salix a letter in which it sought more details about a proposed ulcerative colitis treatment for patients 18 years and older. Salix announced receipt of the letter after stock markets closed Friday.

Shares dipped to $6.94 Monday.

Salix is seeking to regain market share in the gastrointestinal market against increasing generic competition.

“Late this afternoon Salix received a communication from the FDA that the Balsalazide Tablet NDA is approvable,” Bill Forbes, vice president of research and development at Salix, said in the statement on Friday. “Salix will work diligently with the FDA over the next several days to compile a complete response to this approvable letter, which Salix believes will consist of referencing data already available.”