Systems and methods for treating an opioid-induced adverse pharmacodynamic response

A method of treating pain comprising orally co-administering to a patient in need thereof (i) an oral dosage form comprising an analgesically effective amount of morphine or a pharmaceutically acceptable salt thereof and (ii) an effective amount of buprenorphine to prevent or treat an adverse pharmacodynamic response induced by the administration of the morphine or pharmaceutically acceptable salt thereof, wherein the adverse pharmacodynamic response is selected from the group consisting of bowel dysfunction, respiratory depression and a combination thereof and wherein the co-administration is analgesically effective;

• and wherein the morphine or pharmaceutically acceptable salt thereof is administered with a dosing interval of about 12 hours or about 24 hours.