Adverse effect · Ziconotide

How common is severe psychiatric and neurological effects with Ziconotide?

A
Grade A — established in humansLabel boxed warning; approval programme · effect size: large · adverse
Short answerEstablished in humans. Label boxed warning; approval programme point the same way: a large effect. The Prialt label's boxed warning states that severe psychiatric symptoms and neurological impairment may occur during treatment, and that the drug is contraindicated in patients with a pre-existing history of psychosis. Hallucinations, confusion, depression and in some cases suicidality have been reported, and monitoring for cognitive and psychiatric change is built into the label. The dose–harm relationship is the limiting factor in practice.

What the studies show

The Prialt label's boxed warning states that severe psychiatric symptoms and neurological impairment may occur during treatment, and that the drug is contraindicated in patients with a pre-existing history of psychosis. Hallucinations, confusion, depression and in some cases suicidality have been reported, and monitoring for cognitive and psychiatric change is built into the label. The dose–harm relationship is the limiting factor in practice.

Several well-run randomised trials in people, pointing the same way. You can plan around this. It still says nothing about whether the effect is worth the side effects for you.

  1. 1
    Prialt (ziconotide) intrathecal infusion prescribing information.DailyMed, read 29 Oct 2026Boxed warning, contraindication in pre-existing psychosis, intrathecal route, CSF terminal half-life about 4.6 hours, and the 25-amino-acid structure with three disulfide bonds.

In context

Ziconotide is a synthetic copy of a 25-amino-acid peptide from the venom of the cone snail Conus magus, approved as Prialt in 2004 for severe chronic pain in people who need intrathecal therapy. It blocks N-type calcium channels in the spinal cord — a mechanism unrelated to opioids, with no tolerance and no dependence. In its cancer and AIDS pain trial, pain scores improved 53.1% against 18.1% on placebo. It carries a boxed warning for severe psychiatric and neurological effects.

Ziconotide is approved (rx). Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is Ziconotide proven to cause severe psychiatric and neurological effects?
Yes, as far as human trials can show it: Label boxed warning; approval programme. LYO grades this outcome A.
What studies are behind the grade?
The Prialt label's boxed warning states that severe psychiatric symptoms and neurological impairment may occur during treatment, and that the drug is contraindicated in patients with a pre-existing history of psychosis. Hallucinations, confusion, depression and in some cases suicidality have been reported, and monitoring for cognitive and psychiatric change is built into the label. The dose–harm relationship is the limiting factor in practice.
Is Ziconotide approved for this?
Ziconotide is an approved medicine (Approved (Rx)); whether this particular outcome is a licensed indication is stated on the compound page's regulation section.

Other outcomes for Ziconotide

Written and maintained by LYO Research — how pages are written and checked. Reviewed 29 October 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →