Age-dependent Intrathecal Opioid Escalation in Chronic Noncancer Pain Patients

Background. Age and gender may exert important influences on opioid responsiveness and chronic pain. These effects have not been explored in the setting of chronic intrathecal (IT) opioid therapy. The objective of this study was to evaluate the effect of age and sex on IT opioid requirements during the first year after implantation of an intrathecal drug delivery system (IDDS) in chronic noncancer pain patients. Design. Retrospective study. Methods and Patient Population. In this retrospective study, 135 chronic noncancer pain patients consecutively implanted with IDDSs for opioid therapy had their first year postimplant records examined. Results. Similar pain relief was achieved at 12 months after implant in both age groups. Relative to the dose at implant, younger patients had significantly higher rates of IT opioid dose escalation compared with older patients at 12 months (750 +/- 450% in patients <= 50 years old vs 195 +/- 120% in patients >50 years old, P < 0.001). Oral opioid consumption was significantly decreased at 12 months in the older patient population (140 +/- 89 to 62 +/- 35 mg/day at 12 months, P < 0.001, n = 85), while in the younger patient group, there was no change in oral opioid consumption (128 +/- 81 mg/day to 105 +/- 140 mg/day at 12 months, P = 0.65, n = 50). Gender-based analysis (55% males and 45% females) revealed similar reductions in pain scores during the first year postimplant. Oral opioid consumption was significantly higher in females (126 +/- 138 mg) vs males (79 +/- 89 mg) at 12 months postimplant; however, IT opioid dose escalation at 12 months postimplant was not statistically different between males and females. Conclusion. IT opioid dose escalation occurs more steeply in the younger (under 50 years old) IDDS patient population without a concomitant significant decrease in oral consumption of opioids. Age-dependent changes may have important clinical implications on the effectiveness of IT opioid therapy in noncancer pain and its potential complications.