Ziconotide-induced psychosis: a case report

Ziconotide is used intrathecally in the management of severe chronic pain that contains a warning against neuropsychiatric adverse events. The definition of psychiatric events is broad and management strategies are vague. This case report describes a 49-year-old female who was admitted to the acute psychiatric unit to address auditory hallucinations and paranoid ideation persisting for 3 weeks. Approximately 3 months ago, an intrathecal pump with ziconotide was implanted to treat pain. Upon hospital admission, the pump was infusing at a rate of 4.9 mcg/24 hours. Because the drug could not be immediately discontinued, risperidone 0.5 mg nightly was initiated and subsequently, the pump was drained of ziconotide, rinsed, and refilled with normal saline. The patient reported no hallucinations or apparent delusions several hours later and was eventually discharged with resolution of psychotic symptoms and continuation of risperidone for 10 days. Despite the identification of neuropsychiatric effects, limited information is available to characterize the presentation and guide specific management aside from recommendations to discontinue the infusion and possible use of psychotropic medications or necessity for hospitalization. This case report characterizes one presentation of hallucinations and paranoia associated with ziconotide intrathecal infusion. Clinicians should be aware of the management strategies to mediate these adverse effects, including expected time to adverse effect resolution, removal of ziconotide from the pump, and role for short-term use of antipsychotics.