Use of Low Dose Ziconotide as First-Line Intrathecal Monotherapy

Abstract

Ziconotide use in intrathecal drug therapy (IDT) has been limited by dosing related side effects. We examine our experience with ziconotide as a first line IDT monotherapy in patients with chronic pain and present our low and slow dosing algorithm aimed at reducing these patient experienced side effects while adequately managing pain. We retrospectively reviewed demographics, dosing, and outcomes of 15 consecutive patients with complete three-month data sets implanted with intrathecal pain pumps more than three years utilizing ziconotide as a first-line monotherapy. Ziconotide response was assessed at visit 5 (69 ± 10 days) and responders were characterized by having 30% or greater improvement in numerical rating scale scores (n = 7), or activities of daily living (ADL) (n = 7). Eight of our patients had a response in at least one measure (53%). In our eight responders, NRS score decreased from 8.4 ± 0.7 at baseline (consult visit) to 2.4 ± 1.0 at 2.6 months and 4.0 ± 1.3 at most recent follow-up, mean of 12.9 months after implant. We noted that our responders tended to have neuropathic pain with an objective etiology. Initial dosing in 12 patients was 1.2 mcg/day (range for the other three patients was 0.6-1.4). Following initial dosing, visits were at 2-4 week intervals with mean titration doses between 1.1 and 2.8mcg/day. Slight dizziness in two patients and transient urinary retention in one patient occurred, all resolving with dose reduction. No patients had discontinued use at three-month follow-up. We present our experience with low and slow ziconotide IDT as a first-line monotherapy, which showed no side effects resulting in discontinuation of the medication at three-month follow-up. Using a conservative dosing strategy, we were able to effectively treat 53% of patients.