WASHINGTON -- Kelly Knable, a 34-year-old mother of three from the Richmond, Va., suburb of Powhatan, didn't have time to be sick. So when Knable was recovering from surgery that fused several vertebrae in 1998, her doctor minimized her downtime by placing her on a regimen of prescription drugs: first a narcotic called Lortab, then a non-narcotic painkiller called Ultram. For more than two years, she took two 50-milligram Ultram tablets three or four times a day, which allowed her to maintain her busy schedule. Then her doctor moved. Unable to find a new physician to write her prescriptions, Knable...