The city of Chicago says it has reached an agreement with Pfizer committing the drugmaker to disclosing the risks of addiction in its marketing of prescription opioid painkillers. Chicago is suing five pharmaceutical companies, alleging they have misrepresented the benefits of opioids while concealing serious health risks associated with the drugs. Pfizer Inc. is not named in the lawsuit. But Mayor Rahm Emanuel’s office said in its announcement that Pfizer has cooperated with the city’s investigation and the legal action. The agreement with Pfizer also bars it from supporting organization or individual who make inaccurate claims about the risks and benefits of opioids.