Intrathecal ziconotide for complex regional pain syndrome: seven case reports

Ziconotide is a nonopioid analgesic currently indicated as monotherapy, but frequently used in combination with opioids, for the management of severe chronic pain in patients for whom intrathecal (IT) therapy is warranted and who are intolerant of, or whose pain is, refractory to other treatments. There is a paucity of information regarding ziconotide use in patients with complex regional pain syndrome (CRPS). Seven cases in which IT ziconotide was used in patients with CRPS were analyzed. All patients (4 male, 3 female; age range, 14 to 52 years) had experienced inadequate pain relief with multiple conventional and interventional treatments. Three patients received ziconotide monotherapy exclusively; 4 patients received ziconotide monotherapy initially, then combination IT therapy. The mean ziconotide dose was 5.2 mcg/d (range, 0.5 to 13 mcg/d) at initiation and 24.7 mcg/d (range, 0.06 to 146 mcg/d) at the last available assessment. The mean duration of ziconotide therapy was 3.1 years (range, 26 days to 8 years). At ziconotide initiation, the mean visual analog scale (VAS) score was 89.3 mm (range, 75 to 100 mm); VAS scores decreased by a mean of 47.5% (range, 5% to 100%) at last assessment. Of the 5 patients who experienced substantial improvement in pain, edema, skin abnormalities, and/or mobility with ziconotide therapy, 2 have discontinued ziconotide and are pain free. Another patient experienced marked reversal of both edema and advanced skin trophic changes. Adverse events included urinary retention, depression, anxiety, and hallucinations. Adverse events generally resolved spontaneously, with treatment, or with ziconotide discontinuation/dose reduction. Although further studies are required, ziconotide holds promise as an effective treatment for CRPS.