Wyeth (WYE) reported a 12% rise in first-quarter earnings compared with the year-ago quarter. However, sales of the company's top-selling drug, the antidepressant Effexor, slid 6%. Wyeth lost 67 cents, or 1.2%, at $55.66.
Medical-device makers were also under pressure. Stryker (SYK - Get Report) beat first-quarter earnings targets after reporting results following Wednesday's close, but the stock fell $3.09, or 4.5%, to $66.01.