A prospective study evaluating the response of patients with unrelieved cancer pain to parenteral opioids

BACKGROUND. The initiation of continuous parenteral (subcutaneous or intravenous) opioids or a change of opioid (opioid rotation) are treatment options for patients who fail on oral or transdermal opioids. There are insufficient data on the efficacy of these strategies, and comparative data are unavailable. METHODS. The authors prospectively evaluated the efficacy of the start of parenteral opioids in 100 patients with cancer pain who failed on conventional opioids. Pain intensity was rated at rest and during movement from 0 to 10 and was categorized as mild (0-4), moderate (5-6), or severe (7-10): Clinically important pain control was defined as a decrease 2 points in pain intensity and pain intensity < 7. Pain control was evaluated on the second day and again when a clinical decision was made to continue or change parenteral opioid treatment after a median of 6 days. The presence of side effects (absent, mild, moderate, or severe) was evaluated. RESULTS, The mean pain intensity at rest decreased significantly from 6.3 to 4.4 at 48 hours and to 3.4 at the end of treatment. The mean pain intensity during movement decreased significantly from 8.4 to 5.7 at 48 hours and to 4.6 at the end of treatment. Clinically important pain control at rest was seen in 52% of patients at 48 hours, in 71% of patients at the end of treatment; and clinically important pain control during movement was seen in 43% of patients at 48 hours and in 61% of patients at the end of treatment. The proportion of patients with mild pain increased significantly both at rest and during movement. Side effects were present in 78% of patients, and they resolved completely in 32% of patients. The median intravenous morphine equivalent dose increased from 80 mg per day to 135 mg per day at 48 hours and to 201 mg per day at the end of treatment. Results were not different for opioid rotation or for change of route only, nor did the start of antitumour treatment influence the results. In 34% of patients, it was decided to rotate to a second-line parenteral opioid or to start either spinal analgesia or a sedation procedure after a median of 6 days. During follow-up, 18% of patients who were dismissed with parenteral opioids (and 6% of all patients) needed a further change of treatment. CONCLUSIONS. Parenteral opioids improved the balance between analgesia and side effects in patients with cancer pain who failed on conventional opioids, with an important improvement seen in 71% of patients. On the basis of this study, it is concluded that parenteral opioids are a good alternative to spinal opioids. Furthermore, it is suggested that a change of route alone is as effective as opioid rotation. Cancer 2002;94:3049-56. (C) 2002 American Cancer Society.