Pfizer News Sends Blue Chips Down  NEW YORK (Reuters) - The Dow Jones industrial average fell  on Friday after 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; shares opened nearly 19  percent down on trial data for its popular arthritis drug  Celebrex that showed increased risk of heart attack.