New York's attorney general filed a federal lawsuit Monday seeking to stop a manufacturer from discontinuing its drug widely used to treat Alzheimer's patients, arguing the company is illegally driving patients to its newer patented drug to avoid losses from cheaper generic alternatives coming out next year. Attorney General Eric Schneiderman alleges anti-trust and state law violations by Dublin-based Actavis PLC and New York subsidiary Forest Laboratories, which Actavis recently acquired for $28 billion.