Blue chips closed higher Friday thanks to a boost from Pfizer and Merck, whose stock jumped after favorable regulatory reviews of their arthritis painkillers. But that was not enough to finish the week on a high note: The Dow Jones industrial average closed at 10,785.22, up 30.96 points on Friday but down 0.1 percent for the week, ending three weeks of gains. The Nasdaq dropped 2.72 points to 2,058.62, losing 0.9 percent on the week. A Food and Drug Administration panel voted to allow Merck's Vioxx pain-relief drug back on the market and also gave approval to Pfizer to continue selling similar medications, Celebrex and Bextra. The drugs came under scrutiny amid concerns about cardiovascular side effects. WPP, trading as American Depository Receipts on the Nasdaq, closed at $55.74, up 0.7 percent. On the Big Board, Omnicom ended down 0.2 percent at $85.61, and IPG finished 3.4 percent lower at $13.17.