Source: FDA label
| Molecular formula | C102H172N36O32S7 |
|---|---|
| Molecular weight | 2639.2 g/mol |
| Registered trials | 14 |
| PubChem CID | 16135415 |
| Brand names | PRIALT |
Boxed warning: The FDA label for this compound includes a boxed warning, the FDA's strongest safety warning. See the full prescribing information for details.
Mechanism of Action
12.1 Mechanism of Action Ziconotide binds to N-type calcium channels located on the primary nociceptive (A-δ and C) afferent nerves in the superficial layers (Rexed laminae I and II) of the dorsal horn in the spinal cord. Although the mechanism of action of ziconotide has not been established in humans, results in animals suggest that its binding blocks N-type calcium channels, which leads to a blockade of excitatory neurotransmitter release from the primary afferent nerve terminals and antinoci
Living with severe chronic pain that no longer responds to standard treatment leaves few options. Ziconotide, sold as Prialt, is one of the few therapies delivered directly into the spinal fluid for this exact situation.
Key takeaways
- Ziconotide (Prialt) is FDA-approved for severe chronic pain in adults who need intrathecal therapy.
- It works by blocking N-type calcium channels involved in pain signaling in the spinal cord.
- It carries a boxed warning and is reserved for patients intolerant of or refractory to other treatments.
- At least 14 clinical trials have studied ziconotide, including completed Phase 3 chronic pain trials.
- Reported side effects most often involve pain, neuropsychiatric symptoms, and device-related issues, based on FAERS reports.
What ziconotide is
Ziconotide is an N-type calcium channel antagonist given as an intrathecal infusion, meaning it is delivered directly into the fluid around the spinal cord. Its label indicates that it binds to calcium channels on nerve fibers that carry pain signals into the spinal cord's dorsal horn. This binding is thought to block the release of excitatory neurotransmitters from those nerve endings, reducing pain signal transmission. The exact mechanism has not been established in humans, though animal studies support this pathway.
What ziconotide is approved for
Prialt is approved for managing severe chronic pain in adults for whom intrathecal therapy is warranted. It is intended for patients who are intolerant of, or whose pain is refractory to, other treatments such as systemic analgesics, adjunctive therapies, or intrathecal morphine. The label carries a boxed warning, reflecting the seriousness of the risks associated with this therapy.
What the evidence shows
At least 14 clinical trials have investigated ziconotide. Two completed Phase 3 trials, "Prialt (Ziconotide) In Severe Chronic Pain" and the "Ziconotide Effectiveness and Safety Trial in Patients With Chronic Severe Pain," evaluated its use specifically in this severe chronic pain population. A newer trial exploring ziconotide for chemotherapy-induced peripheral neuropathy has not yet begun recruiting.
Reported side effects
FAERS reports for ziconotide are dominated by pain (362 reports), device issues related to the intrathecal delivery system (313), and off-label use (301). Neuropsychiatric reactions are also prominent, including confusional state (205), hallucination (168), and dizziness (157), alongside nausea (204) and reports of the drug being ineffective (241). These figures reflect the number of reports submitted, not confirmed incidence or a causal link to ziconotide.
FAQ
What is ziconotide used for?
Ziconotide, marketed as Prialt, is approved for managing severe chronic pain in adults who require intrathecal therapy. It is meant for patients who cannot tolerate or do not respond to other pain treatments, including systemic analgesics or intrathecal morphine.
How does ziconotide work?
Ziconotide blocks N-type calcium channels on nerve fibers that transmit pain signals into the spinal cord. This is thought to reduce the release of chemical messengers that carry pain signals, though the precise mechanism in humans has not been fully established.
Does ziconotide have a boxed warning?
Yes, the FDA label for ziconotide includes a boxed warning. It is generally reserved for patients who have not responded to, or cannot tolerate, other chronic pain treatments.
What side effects are reported with ziconotide?
The most frequently reported issues include pain, problems with the intrathecal delivery device, and neuropsychiatric symptoms such as confusion, hallucination, and dizziness. Nausea is also commonly reported. These are counts of submitted reports, not confirmed rates or proof that ziconotide caused the reaction.
Is there clinical trial evidence supporting ziconotide's use?
Yes, at least 14 clinical trials have studied ziconotide, including two completed Phase 3 trials specifically in patients with severe chronic pain. Additional research, such as a trial in chemotherapy-induced peripheral neuropathy, is in earlier stages.
This page is an editorial information resource. It does not sell, prescribe, or recommend any medication.
Content is editorial information, not medical advice. Talk to your doctor before any treatment decision.
Sources: FDA label (DailyMed) ClinicalTrials.gov FDA Adverse Event Reporting System (FAERS) PubChem
Updated 2026-09-19