A Randomized, Double-Blind, Placebo-Controlled Study of Intrathecal Ziconotide in Adults with Severe Chronic Pain

Safety and efficacy data from a study of slow intrathecal (IT) ziconotide titration for the management of severe chronic pain are presented. Patients randomized to ziconotide (n = 112) or placebo (n = 108) started IT infusion at 0.1 μg/hour (2.4 μg/day), increasing gradually (0.05–0.1 μg/hour increments) over 3 weeks. The ziconotide mean dose at termination was 0.29 μg/hour (6.96 μg/day). Patients' baseline Visual Analogue Scale of Pain Intensity (VASPI) score was 80.7 (SD 15). Statistical significance was noted for VASPI mean percentage improvement, baseline to Week 3 (ziconotide [14.7%] vs. placebo [7.2%; P = 0.036]) and many of the secondary efficacy outcomes measures. Significant adverse events (AEs) reported in the ziconotide group were dizziness, confusion, ataxia, abnormal gait, and memory impairment. Discontinuation rates for AEs and serious AEs were comparable for both groups. Slow titration of ziconotide, a nonopioid analgesic, to a low maximum dose resulted in significant improvement in pain and was better tolerated than in two previous controlled trials that used a faster titration to a higher mean dose.