Use of Low Dose Ziconotide as First-Line Intrathecal Monotherapy.

BACKGROUND: 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.

METHODS: 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.

RESULTS: 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 2.8 mcg/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.

DISCUSSION: 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.