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Pain & nerve

Ziconotide

Also called Prialt, SNX-111, ω-conotoxin MVIIA

Ziconotide is a lab-made copy of a toxin from a fish-hunting cone snail. It is a non-opioid pain drug given only by a pump into the spinal fluid, for severe long-term pain that other treatments have not controlled.

FDA-approvedApproved by the FDA for at least one use after large human trials.

All printable flashcards

Drawn from its published sequence: 25 residues, one bead each. Dashed arcs are ring bonds.

Overview

Ziconotide is a lab-made copy of a toxin from a fish-hunting cone snail. It is a non-opioid pain drug given only by a pump into the spinal fluid, for severe long-term pain that other treatments have not controlled.

How it works

Established: ziconotide blocks N-type (Cav2.2) voltage-gated calcium channels on pain-sensing nerve endings in the spinal cord's dorsal horn. This stops the release of pain-signaling chemicals. It does not act on opioid receptors, so it does not cause opioid tolerance or withdrawal. It has to be given into the spinal fluid because it does not reach the spinal cord well from the blood.

What research shows

  • Staats et al., JAMA 2004 (cancer or AIDS pain, 68 vs 40): pain score improved 53.1% vs 18.1% with placebo (summarized in a review).
  • Rauck et al., 2006 (slow titration, 112 vs 108): pain improved 14.7% vs 7.2% at day 21 (p=0.036); this schedule underlies the label dosing (FDA label; review).
  • Faster titration to high doses in earlier trials caused many more nerve and psychiatric side effects (FDA label).

Doses studied in people

Study or labelDose usedSource
FDA label (Prialt), severe chronic pain, intrathecal infusionStart ≤2.4 mcg/day (0.1 mcg/h); increase by up to 2.4 mcg/day no more than 2-3 times per week; maximum 19.2 mcg/day (0.8 mcg/h)1

Given only intrathecally by implanted or external pump under specialist care; the label limits the start dose and how fast it is increased.

Read this first: these are the amounts given to participants in published studies or written on official prescribing labels, reported for reference. They are not recommendations. Trial doses were chosen for specific patients under medical supervision, and a dose that is safe in one person can be harmful in another.

Safety

  • BOXED WARNING: severe psychiatric symptoms and neurological impairment (confusion, hallucinations, mood or consciousness changes); contraindicated with a history of psychosis (FDA label).
  • Common in the slow-titration trial vs placebo: dizziness 46% vs 13%, nausea 40% vs 29%, confusion 15% vs 5%, nystagmus 8% vs 0% (FDA label).
  • Creatine kinase above normal in 40% of patients; rare myopathy and rhabdomyolysis (FDA label).
  • Meningitis in 3% (most with external pumps or catheters) (FDA label).

Report side effects of any drug or product to the FDA through MedWatch. For a possible poisoning in the US, call Poison Control at 1-800-222-1222.

Storage and stability

Refrigerate at 2-8°C, do not freeze, protect from light; diluted solution may be refrigerated up to 24 hours (FDA label).

General lab handling, not instructions for personal use. See Storage and stability.

History

The peptide came out of Baldomero Olivera's cone-snail venom research at the University of Utah; Michael McIntosh isolated it in the early 1980s. It was fully synthesized in 1987 and developed as SNX-111 by Neurex, later Elan. The FDA approved it as Prialt on December 28, 2004, and the EU in 2005.

Common questions

Is ziconotide FDA-approved?

Yes. It was approved as Prialt in 2004 for severe long-term pain that needs treatment delivered into the spinal fluid, and it carries a boxed warning 1.

Where does ziconotide come from?

It is a lab-made copy of a toxin from a fish-hunting cone snail, found through venom research at the University of Utah 5. It blocks N-type calcium channels on pain nerves in the spinal cord, which stops pain signals being passed on 13.

What does the research show?

In one trial of cancer or AIDS pain, pain scores improved 53.1% versus 18.1% with placebo 3. A slower-dosing trial found 14.7% versus 7.2% improvement at day 21, and faster dose increases in earlier trials caused more side effects 13.

What doses are on the FDA label?

The label lists a start of no more than 2.4 mcg per day by spinal infusion, raised slowly to a maximum of 19.2 mcg per day 1. It is given only by pump under specialist care 1.

What are the main risks?

The boxed warning covers severe psychiatric and nerve effects such as confusion and hallucinations, and it must not be used with a history of psychosis 1. Dizziness, nausea, raised muscle enzymes and meningitis (mostly with external pumps) were also reported 1.

How is ziconotide stored?

It is kept in the fridge at 2 to 8°C, not frozen and protected from light 2. Diluted solution may be refrigerated for up to 24 hours 2.

Related compounds

Pain & nerveFDA-approvedFlashcard

Difelikefalin

Korsuva · Kapruvia

Difelikefalin is a small lab-made peptide that switches on kappa opioid receptors, mostly outside the brain.

Sources

  1. PRIALT (ziconotide) intrathecal infusion prescribing information (2023) FDA label
  2. Prialt prescribing information (clinical studies, storage) FDA label
  3. Ziconotide review in Therapeutics and Clinical Risk Management (doi:10.2147/TCRM.S4438) PubMed review
  4. ChEBI: ω-conotoxin MVIIA (CHEBI:142406) Journal
  5. Ziconotide (Wikipedia; discovery history) Journal
  6. WADA 2026 Prohibited List Regulatory

Last reviewed 2026-10-25 · How we research · Found an error? See our corrections policy.