The American Medical Association is considering putting the brakes on its controversial practice of selling information about its members to the nation's largest drug marketers. The AMA generates more than $20 million in revenue from selling doctors' biographies, which include everything from medical license information and private telephone numbers to federal identification data issued to track controlled substances. This information is an important marketing tool, giving pharmaceutical companies valuable insight into which doctors to target for the latest brand-name drugs. Some lawmakers, prosecutors and employers say the industry's practices are driving up the usage of prescription drugs and overall health-care costs.