Patients with both chronic non-cancer (e.g., post-operative surgical pain) and cancer pain present a number of challenges to their treating physicians. One such challenge is whether to use oral opioids in their treatment plan; some patients are not good candidates due to a combination factors, including poorly defined pathology, significant psychosocial problems, manipulative behavior, dependence, and tolerance. However, opioid therapy can yield adequate relief in more than three quarters of patients with severe pain. This justifies its use as a first-line therapy for patients with moderate to severe cancer pain or post-operative surgical pain. Many patients with mild pain respond adequately to non-opioid drugs, and these should be considered first in such cases. Since the response to opioids is highly individual, sequential trials (so-called opioid rotation) may be needed to identify the drug that yields the most favorable balance between analgesia and side effects.
Although the oral route is usually preferred for chronic opioid therapy, other routes may be needed for diverse reasons, including dysphagia, impaired gastrointestinal function, and noncompliance with oral agents. Opioid delivery can be accomplished via many other approaches, including the transdermal route, continuous subcutaneous or intravenous infusion, and intraspinal infusion. However, there continues to be a need for effective methods of delivery that do not involve injection and yet accomplish the goal of immediate and lasting pain relief.