Opioid pharmacotherapy in the management of cancer pain. A survey of strategies used by pain physicians for the selection of analgesic drugs and routes of administration

Background. This survey documents the strategies used by pain control physicians in the selection of opioid drugs and routes of administration in the management of inpatients referred to a cancer pain service. Methods. The following approaches were prospectively evaluated during the treatment of 100 consecutive inpatients: 1) the influence of the evaluation of the goals of care on decision making, 2) selection of opioid drugs, 3) indications for changing opioid drugs and the frequency with which this strategy is used, and 4) selection of route of administration. Results. Eighty of the 100 patients underwent a total of 182 changes in drug, route, or both drug and route before discharge or death. The major reasons for change were to improve the convenience of treatment regimen in the setting of adequate pain relief (31.4%), diminish side effects in the setting of controlled pain (25.0%), reduce the invasiveness of therapy in the setting of controlled pain (19.3%), and simultaneously improve pain control and reduce opioid toxicity (17.7%). When opioid toxicity was the reason for change, physicians changed the opioid drug in 71% of cases and the route in 29%. When convenience or invasiveness were targeted, the physicians changed the route in 61% of cases and the opioid in 39%. Forty-four patients required one or more change in the opioid, and 20 required 2 or more changes (range, 2-6 changes). At the time of discharge (n = 82), morphine was more commonly selected than hydromorphone or fentanyl (39% vs. 23% vs. 17%) and the routes of administration were oral (57%), transdermal (18%), intravenous (18%), subcutaneous (5%), and intraspinal (4%), Therapeutic changes were associated with improvement in physician-recorded pain intensity and a lower prevalence of cognitive impairment, hallucinations, nausea and vomiting, and myoclonus among patients who were discharged from the hospital. Conclusions. These data illustrate the application of strategies for selections of opioid drugs and their route of administration that are recommended in current guidelines for the management of cancer pain.