Pubdate: Fri, 22 May 1998 Source: Chicago Tribune (IL) Contact: Website: http://www.chicago.tribune.com/ Author: From Tribune News Services: Compiled by Steven Morris BUSINESS BRIEFING: PFIZER Pfizer Inc. said Thursday it will warn paramedics and emergency-room physicians not to treat patients on its impotence pill Viagra with nitroglycerin. The warning sent Pfizer shares down $3.69, to $109.12. Nevertheless, Pfizer shares have more than doubled in the last year on prospects for Viagra. It reached an all-time high of $121.75 on April 21. Viagra's label already contains a warning that it shouldn't be used by those taking organic nitrates such as nitroglycerin, primarily used to treat angina, or chest pain. Pfizer said it will send out 10,000 letters this week to emergency-room personnel who might not realize they're treating Viagra users. Viagra, which is easier to use than other impotence remedies on the market, became one of the best-selling U.S. drugs after its April introduction. Meanwhile, the nation's leading discount chains are vying in a Viagra price war. Kmart Corp. has taken out national newspaper ads to promote its price of $39.99 for a five-tablet prescription. - --- Checked-by: Melodi Cornett