Bowel function after tapentadol and oxycodone immediate release (IR) treatment in patients with low back or osteoarthritis pain.

Objectives: Constipation is a common side effect of opioid therapy. Tapentadol immediate release (IR) was better tolerated than oxycodone IR in 2 clinical trials involving patients with low back or osteoarthritis pain. The objective of this study was to examine patient-reported bowel function during those trials.
Methods: Bowel function was assessed during secondary post hoc analyses using: the bowel movement questionnaire (BMQ; 10-d trial); the Patient Assessment of Constipation Symptoms questionnaire (PAC-SYM; 90-day trial); and laxative use (both trials). Random effects maximum likelihood regressions were run to examine PAC-SYM data. BMQ data were analyzed using 1-way analyses of variance and a multinomial logistic regression. Rates of laxative use were compared using χ(2) statistics.
Results: The 10- and 90-day trials consistently showed that tapentadol IR caused less impairment of bowel function than oxycodone IR. BMQ data were comparable between patients receiving tapentadol IR and placebo, and better versus oxycodone IR including: lower proportion of days where bowel movement was absent (P<0.05); lower risks of reporting hard stools (P<0.001); and moderate or severe straining (P<0.001). All PAC-SYM summary scores (abdominal, rectal, stool, overall) indicated fewer symptoms among patients receiving tapentadol IR versus oxycodone IR (P<0.001). In both trials, rates of laxative use was lower for tapentadol IR treatment groups versus oxycodone IR (P<0.001).
Discussion: Patient-reported bowel function associated with tapentadol IR treatment was similar to that associated with placebo (10-d trial) and significantly better than that associated with oxycodone IR treatment (10- and 90-d trials).