Objective: To evaluate the impact of an extended-release, once-daily morphine sulfate formulation on depressive symptoms and neurocognition in patients with chronic nonmalignant pain.
Design: Prospective, open-label, one-group trial with a pretest-posttest design.
Setting: Outpatient pain management clinic.
Patients and intervention: Chronic nonmalignant pain patients inadequately controlled with short-acting opioid analgesics and eligible for treatment with once-daily morphine sulfate were initiated on a dose at or near the morphine-equivalent dose of the short-acting regimen.
Outcomes: The following assessments were made at baseline and 4 weeks after initiating intervention: pain intensity, pain unpleasantness, pain suffering, pain behaviors, Beck Depression Inventory, and cognitive function.
Results: Eighty-four patients provided usable data. Pain intensity, unpleasantness, and suffering scores were significantly reduced at follow-up (P = 0.001). The mean Beck Depression Inventory scores were significantly lower at follow-up (P = 0.001). Significant improvements were seen in scores at follow-up on the three validated neurocognitive tests: the digit span test, the digit symbol substitution test, and the paced auditory serial addition test (P = 0.001).
Conclusions: Achieving adequate pain control with once-daily morphine was associated with a reduction in pain and improvements in depressive symptoms and cognitive functioning in the short term.