Objective: To evaluate the outcomes associated with the use of controlled-release (CR) oxycodone for up to 3 years in the treatment of noncancer pain.
Methods: Adult patients who previously participated in controlled trials of CR oxycodone for osteoarthritis pain, diabetic neuropathy pain, or low back pain, and who continued to require opioid analgesia for moderate or severe pain, were enrolled in an open-label, uncontrolled, registry study. Data collected over time included dose, pain severity on a numeric scale, treatment acceptability, adverse events, and descriptions of problematic drug-related behavior.
Results: Two hundred thirty-three patients were enrolled. When the study closed, 141, 86, and 39 patients had taken CR oxycodone for at least 1, 2, and 3 years, respectively; mean duration of treatment was 541.5 days. Among the 219 intent-to-treat patients (received at least 1 dose and provided at least 1 postdose study observation), the mean (SD, range) daily dose was 52.5 (±38.5, 10.0 to 293.5) mg. Before the end of month 3, 44% required an increase in total daily dose; this dropped to 23% during months 4 to 6, to 17% during months 10 to 12, and remained at approximately 10% for each time interval thereafter (range 8% to 13%). Among the large majority of patients with stable or lower dose requirements after the initial 3 months of treatment, the average pain intensity ratings were unchanged or improved for approximately 70% to 80% of patients at all subsequent time points through month 33, and for 54% (7/13 patients) at month 36. A decrease in pain was initially seen by the end of month 3, and for the majority of patients, the Average Pain Intensity score remained the same, better, or minimally worse (<3 points) for the remainder of the 3-year study period. The most common adverse events were constipation and nausea, and the incidence of these events declined over time on treatment. Investigators reported 6 cases (2.6%) of possible drug misuse but no evidence of de novo addiction was observed.
Discussion: These registry data demonstrate that a subgroup of patients with noncancer pain experienced prolonged relief with tolerable side effects and modest need for dose escalation during long-term therapy with CR oxycodone.