Updated from 2:04 p.m. EDT

Shares of NBTY ( NTY) were among the worst-performing health and pharmaceutical stocks Friday after the company reported weaker-than-expected third-quarter financial results.

The nutritional supplements company posted third-quarter earnings of 37 cents a share on sales of $400 million. Analysts polled by Thomson First Call had expected it to earn 48 cents a share on sales of $416.4 million. Weakness in the company's Vitamin World unit contributed to the third-quarter shortfall. A year ago, NBTY earned pro forma earnings of 37 cents a share on sales of $308 million. Shares of NBTY traded down $4.82, or 19.7%, to $19.68.

Closure Medical ( CLSR) fell after it reported better-than-expected second-quarter financial results but warned that third-quarter earnings and sales would fall short of expectations. The biomaterial medical device company earned 17 cents a share during the second quarter on sales of $11.3 million. Analysts had expected it to earn 14 cents a share on sales of $10.7 million. Looking ahead, Closure expects third-quarter earnings of 12 cents to 15 cents a share on sales of $9.5 million to $10.5 million. Analysts were looking for 18 cents a share on sales of $12.1 million. Shares of Closure Medical traded down $2.92, or 14%, to $17.90.

Shares of Quinton Cardiology Systems ( QUIN) fell after the company reported mixed second-quarter earnings and sales results and warned that third-quarter earnings could fall short of expectations if they come in at the low end of its forecast. Excluding a one-time gain, the cardiology products maker earned 8 cents a share during the second quarter on sales of $21.6 million. Analysts had expected it to earn 8 cents a share on sales of $21.9 million. Looking ahead, it expects third-quarter earnings of 8 cents to 11 cents a share on sales of $22 million to $23.5 million. Analysts are looking for 11 cents a share on sales of $22.9 million. Shares of Quinton Cardiology Systems traded down $1.96, or 19.9%, to $7.90.

Shares of Auxilium Pharmaceuticals ( AUXL) were recently trading below their offering price on the company's first day of trading as a public company. After cutting the size and price of its IPO twice, the specialty pharmaceutical company priced 5.5 million shares at $7.50 apiece, raising about $42 million. Deutsche Bank Securities led the underwriting syndicate, which included Piper Jaffray and Thomas Weisel Partners. Shares of Auxilium Pharmaceuticals traded down 30 cents, or 4%, to $7.20.

Other health care volume movers included Boston Scientific ( BSX), up 32 cents to $33.59; Pfizer ( PFE), down 21 cents to $32.30; Amgen ( AMGN), down 74 cents to $55.36; Schering-Plough ( SGP), down 15 cents to $18.75; and Genentech ( DNA), down 24 cents to $48.26.