Sleep improves when patients with chronic OA pain are managed with morning dosing of once a day extended-release morphine sulfate (AVINZA®): Findings from a pilot study

Study objective: To investigate the effect of once-a-day extended release of morphine sulfate AVINZA® (A-MQD) on polysomnographic measures of sleep in a population of chronic osteoarthritic pain patients with sleep difficulties.Design: Single-center, single-blind, placebo-lead-in, 30 mg or 60 mg. Patients’ sleep and neurocognition were objectively measured at a sleep laboratory, and patients self-rated their pain, sleep, and other functions.Participants: Thirty-four participants (26 to 75 years old) complaining of sleep difficulties and chronic, stable pain secondary to hip or knee osteoarthritis.Interventions: Participants had a screening visit on current pain medication and then, following a singleblind placebo run-in period, received 30 mg/d of A-MQD for six days. At day 6, doses for participants with incomplete pain relief on the Brief-Pain-Inventory (BPI) pain scale were increased to 60 mg/d. Treatment continued for another eight days at the new dose level (14 days for a subgroup at 60 mg/d). Sleep was objectively measured by all-night polysomnography (PSG) at screening while on the participants’ current pain therapy, at baseline following a placebo run-in and at the end of treatment while on A-MQD.Outcome measures: PSG parameters evaluated included Total-Sleep-Time (TST), Wake-timeafter-Sleep-Onset (WASO), Sleep-Efficiency (SE), Latency-to-Persistent Sleep (LPS), Latency-to-REM-sleep, the Number-of-Awakenings (NAW), the time spent in each stage of sleep, and REM-sleep-latency. Subjective evaluations included participants’ estimations of sleep time and sleep quality, the Epworth-Sleepiness-Scale (ESS), the BPI, and participant acceptance of and relief due to current therapy. Assessments of neurocognitive function were also made.Results: Sleep initiation and maintenance tended to improve with A-MQD as demonstrated by the increases in TST and SE and decreases in WASO and NAW as compared with placebo-baseline values. Sleep architecture was preserved by the study drug and some increases in stage 2 and 3/4 sleep were seen compared with placebo baseline. Subjective ratings of sleep quality and sleep time were significantly improved with treatment, as were BPI scores and ratings of medication acceptance and pain relief. A-MQD was generally well tolerated.Conclusions: A-MQD was an effective treatment for pain, and this study treatment was associated with improvement of both objective and subjective sleep parameters in participants with chronic osteoarthritic pain.