COLORADO SPRINGS, Colo. (May 18, 2004) - The United States Anti-Doping Agency (USADA) announced Tuesday that Faruk Sahin of Fort Carson, Colo., an athlete in the sport of wrestling, tested positive at the U.S. National Championships on Apr. 10, 2004 in Las Vegas, Nev.      He tested positive for phentermine, a prohibited substance under the rules of the Fédération Internationale des Luttes Associées (FILA), which is the international federation for the sport of wrestling.  Sahin won the 145.5-pound division at the U.S. National Championships in the Greco-Roman competition.     Phentermine is a stimulant, which is a prohibited substance during in-competition testing.      Sahin, 28, accepted and began serving the provisional suspension on May 18, 2004.  By accepting the provisional suspension, Sahin agreed not to compete in any competitions under the jurisdiction of FILA, USA Wrestling or the United States Olympic Committee, including the U.S. Olympic Trials, pending the resolution of the doping violation.      He will receive credit for the period of the time he has served the provisional suspension should a doping violation be determined at an arbitration hearing. According to FILA rules, if Sahin did not accept the provisional sanction, his suspension would begin on the date of the decision of the arbitration panel.     USADA became the independent anti-doping agency for U.S. Olympic, Pan Am and Paralympic athletes on Oct. 2, 2000. USADA is the independent anti-doping agency for Olympic sports in the United States, and is responsible for managing the testing and adjudication process for U.S. Olympic, Pan Am and Paralympic athletes. USADA is equally dedicated to preserving the integrity of sport through research initiatives and educational programs.