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approvedPain & Recovery

Ziconotide

Also known as: Prialt, SNX-111, Omega-conotoxin MVIIA, ω-MVIIA

Ziconotide (Prialt) is a synthetic 25-amino acid peptide derived from the omega-conotoxin MVIIA found in the venom of the marine cone snail Conus magus. FDA-approved in 2004, it is the first and only intrathecally administered N-type calcium channel blocker for the management of severe chronic pain in patients who are intolerant of or refractory to other analgesic therapies. It represents a landmark achievement in venom-derived drug development.

3 cited references·5 researched benefits

Quick Answer

Ziconotide (Prialt) is a synthetic 25-amino acid peptide derived from cone snail venom that selectively blocks N-type voltage-gated calcium channels in the spinal cord dorsal horn. FDA-approved in 2004, it is administered intrathecally via implanted pump for severe chronic pain refractory to opioids and other analgesics. It is non-addictive and does not produce tolerance, making it a critical option for patients with intractable pain from cancer, AIDS, or neuropathic conditions.

Key Facts

Mechanism
Ziconotide selectively and reversibly blocks presynaptic N-type voltage-gated calcium channels (Cav2.2) in the superficial laminae of the spinal cord dorsal horn. By blocking calcium influx into primary afferent nerve terminals, it inhibits the release of pronociceptive neurotransmitters including substance P, glutamate, and calcitonin gene-related peptide (CGRP). This disrupts pain signal transmission from peripheral nociceptors to second-order neurons in the spinothalamic tract. Unlike opioids, ziconotide does not act on opioid receptors, produces no tolerance, has no respiratory depressant effects, and carries no addiction potential.
Research Status
approved
Half-Life
~4.6 hours (in CSF)
Molecular Formula
C₁₀₂H₁₇₂N₃₆O₃₂S₇
Primary Use
Pain & Recovery
Table of Contents

Benefits

  • Effective for severe chronic pain refractory to opioids, local anesthetics, and other intrathecal agentsstrong
  • Non-addictive with no tolerance development — pain relief is sustained over years of continuous infusionstrong
  • No respiratory depression — a major safety advantage over intrathecal opioidsstrong
  • Effective in both nociceptive and neuropathic pain syndromes, including cancer pain and AIDS-related neuropathystrong
  • Provides an alternative for patients who have failed or cannot tolerate intrathecal morphinemoderate

Dosage Protocols

RouteDosage RangeFrequencyNotes
Intrathecal infusion (implanted pump)0.1–2.4 mcg/day initially, up to 19.2 mcg/day maximumContinuous infusionMust be titrated slowly (no more than 2.4 mcg/day increase per week) via programmable intrathecal pump (e.g., Medtronic SynchroMed). Rapid titration increases risk of serious neuropsychiatric adverse events.
Intrathecal infusion (external microinfusion)0.1–2.4 mcg/day initiallyContinuous infusionExternal pump used during initial trialing period before permanent pump implantation. Allows dose optimization in a monitored setting.

Medical disclaimer

Dosage information is provided for educational reference only. Always follow your prescriber's instructions and consult a qualified healthcare provider before starting any peptide protocol.

Side Effects

  • Dizziness, confusion, and cognitive impairment — most common CNS effects, dose-relatedcommon
  • Nausea, vomiting, and headache during titration phasecommon
  • Gait disturbance and nystagmus — dose-dependent neurological effectscommon
  • Severe psychiatric symptoms including hallucinations, psychosis, and suicidal ideation (FDA black box warning)serious
  • Elevated creatine kinase levels (rhabdomyolysis risk at high doses)serious
  • Meningitis risk associated with intrathecal delivery system (not drug-specific)serious

Frequently Asked Questions

Why is ziconotide only given intrathecally?
Ziconotide cannot cross the blood-brain barrier effectively when given intravenously or subcutaneously, so it must be delivered directly into the cerebrospinal fluid (CSF) via an intrathecal pump to reach its target — the N-type calcium channels in the spinal cord dorsal horn. Additionally, systemic administration would cause unacceptable cardiovascular side effects (severe hypotension) due to N-type calcium channel blockade in peripheral blood vessels.
How does ziconotide compare to intrathecal morphine?
Both are FDA-approved for intrathecal pain management, but they work through entirely different mechanisms. Morphine activates opioid receptors and produces tolerance, requiring dose escalation over time. Ziconotide blocks calcium channels and does not produce tolerance — the same dose can remain effective for years. Ziconotide also has no respiratory depression risk and no addiction potential. However, ziconotide has a narrower therapeutic window and more neuropsychiatric side effects (confusion, hallucinations), requiring careful slow titration.
Is ziconotide really derived from snail venom?
Yes. Ziconotide is a synthetic version of omega-conotoxin MVIIA, a peptide naturally produced by the cone snail Conus magus. Cone snails are predatory marine mollusks that inject venom to paralyze prey. Their venom contains hundreds of small, highly selective peptide toxins (conotoxins) that target ion channels with remarkable specificity. Baldomero Olivera and colleagues at the University of Utah identified MVIIA as a potent and selective N-type calcium channel blocker in the 1980s, leading to its development as the drug Prialt.
What are the risks of the intrathecal pump required for ziconotide?
The implanted intrathecal pump (typically Medtronic SynchroMed) requires surgical placement under the skin of the abdomen with a catheter threaded into the spinal canal. Risks include surgical site infection, meningitis, catheter migration or kinking, pump malfunction, and CSF leak. The pump reservoir must be refilled every 1–3 months by a pain specialist. Despite these challenges, the pump system is well-established and has been used for intrathecal drug delivery for decades.

References

  1. 1
    Omega-conotoxin MVIIA: a selective blocker of N-type calcium channels in neurons(2000)PubMed ↗
  2. 2
    Ziconotide: a review of its pharmacology and use in the management of pain(2004)PubMed ↗
  3. 3
    Intrathecal ziconotide for severe chronic pain: safety and efficacy findings from an open-label, long-term trial(2006)PubMed ↗

Latest Research

Last updated: 2026-02-19