According to the Institute of Medicine, there are approximately 100 million Americans—more than those affected by heart disease, cancer, and diabetes—who suffer from chronic pain. When untreated, chronic pain is associated with functional loss and disability, reduced quality of life, high health care costs, and premature death. According to the Institute of Medicine Pain, the cost of pain to society is between $560 and $635 billion annually due to loss of productivity and medical costs. It is important that these patients, whose chronic pain often interrupts daily life, gain and maintain access to adequate pain relief. Opioid analgesics play an important role in the management of moderate to severe pain and are the most widely prescribed products for pain, with 259 million prescriptions written in 2013.