Pfizer Hikes Warning on Bextra Skin Risk  NEW YORK (Reuters) - Pfizer Inc. &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=PFE.N target=/stocks/quickinfo/fullquote"&gt;PFE.N&lt;/A&gt; said on Friday it  is sending additional information to healthcare professionals  about its arthritis drug Bextra, a COX-2 product in the same  class as the withdrawn drug Vioxx.