Is ziconotide FDA-approved, and what does the research show?

What is ziconotide?

Ziconotide is a prescription pain medicine sold in the United States as Prialt ¹. It is a peptide, a short chain of amino acids, the building blocks of proteins, and it has 25 of them ¹. The label describes it as a synthetic equivalent of a peptide that occurs naturally in a fish-eating marine snail ¹.

Ziconotide is not a wellness, weight-loss or performance peptide. Its one approved use is severe chronic pain in adults whom other treatment has not helped or who cannot tolerate it ¹. The label calls it "a non-opioid and non-NSAID analgesic agent" ¹. An analgesic is a pain reliever, and opioids are the morphine family of drugs. NSAIDs, nonsteroidal anti-inflammatory drugs, are pain relievers that also reduce inflammation.

Ziconotide is delivered only by intrathecal infusion: a pump sends it continuously through a catheter, a thin tube, into the cerebrospinal fluid ¹. That is the fluid surrounding the spinal cord. The label states that it "is not intended for intravenous administration," meaning delivery into a vein ¹.

Is ziconotide FDA-approved?

Yes, as a prescription drug with one approved use. FDA approved Prialt (ziconotide) on December 28, 2004, under NDA 021060, a new drug application ². Its marketing status is "Prescription" as of November 9, 2026, the date of the Drugs@FDA record's data ². That record lists four Prialt products: three vial sizes marked "Prescription," which the current label also lists, and a fourth marked "Discontinued" ¹, ².

The label gives a single indication, the use FDA approved. Prialt "is indicated for the management of severe chronic pain in adult patients for whom intrathecal therapy is warranted, and who are intolerant of or refractory to other treatment, such as systemic analgesics, adjunctive therapies, or intrathecal morphine" ¹. "Refractory" describes pain that has not responded to treatment. "Systemic analgesics" are pain relievers that act through the whole body rather than at the spine.

Prialt is prescription-only, and the label says it is to be given "by or under the direction of a physician experienced in the technique of intrathecal administration and who is familiar with the drug and device labeling" ¹. Section 17 of the label says Prialt is "For use only in the Medtronic SynchroMed® II and SynchroMed® III Infusion System," a named pump system ¹. The label's Highlights, its opening summary, name "a programmable implanted variable-rate microinfusion device or an external microinfusion device and catheter" ¹. The full label's dosing section names only that system; the external-device wording survives in the Highlights and the meningitis warning ¹.

See the FDA status of every peptide, updated weekly.

How does ziconotide work?

The label states that "the mechanism of action of ziconotide has not been established in humans" ¹. It does state where the drug binds. Ziconotide attaches to N-type calcium channels, one kind of the pores that let calcium into nerve cells ¹. The label places those channels on the pain-sensing nerves that run into the dorsal horn, the part of the spinal cord that receives their signals ¹. The label does not say whether the binding was shown in human or animal tissue ¹.

The next step has been studied in animals. The label says results in animals "suggest that its binding blocks N-type calcium channels" ¹. The same animal results, it says, suggest the block stops the nerve endings from releasing excitatory neurotransmitters ¹. Those are the chemical messengers that pass a signal to the next nerve cell. The label's term for the result is "antinociception," a reduced response to pain signals ¹.

Ziconotide is not an opioid. It "does not bind to opioid receptors and its pharmacological effects are not blocked by opioid antagonists," the drugs that reverse opioids ¹. The label also states that it "is not an opiate and cannot prevent or relieve the symptoms associated with the withdrawal of opiates" ¹.

As a peptide, ziconotide "is expected to be completely degraded" by enzymes found widely in the body ¹. The label refers to "low plasma ziconotide concentrations," plasma being the liquid part of blood ¹. During 5 or 6 days of continuous infusion, plasma levels "could not be quantified in 56% of patients" ¹. Its half-life in cerebrospinal fluid, the time for half of it to clear, was about 4.6 hours ¹.

What does the research show?

Ziconotide is approved by FDA for a use, the management of severe chronic pain ¹. The label says its efficacy "was studied in three double-blind, placebo-controlled, multicenter studies in a total of 457 patients (268 PRIALT, 189 placebo)" ¹. The placebo was a dummy infusion, and double-blind means neither patients nor doctors knew who received which. Multicenter means each study ran at several sites.

The three studies used two titration schedules, titration being the stepwise raising of a dose ¹. The slow schedule raised the dose two to three times a week over 21 days ¹. The fast schedule raised it daily over 5 to 6 days to a higher maximum, and it "resulted in less tolerability and substantially more frequent adverse events" ¹.

The label reports the slow-schedule trial in detail ¹. It enrolled adults whose severe chronic pain was not adequately controlled with intrathecal analgesics, including morphine, or who could not tolerate analgesics ¹. It was randomized, meaning chance decided each patient's group, and 112 received ziconotide and 108 received placebo ¹. Nearly every patient, 98 percent, was also receiving opioids ¹. Pain was scored on the Visual Analog Scale of Pain Intensity, a 100-millimeter line on which 100 is the worst possible pain ¹.

Both groups began at a mean score of 81 ¹. After three weeks the ziconotide group's score had improved by a mean of 12 percent and the placebo group's by 5 percent ¹. The 95 percent confidence interval for the difference, the range in which the true gap plausibly lies, ran from 0.4 to 13 percentage points ¹. The label calls the difference statistically significant in an intent-to-treat analysis, one that counts every randomized patient ¹.

A report published in May 2006 describes a trial with the same arm sizes and length, though the label does not name it ³. Its authors sign as the Ziconotide 301 Study Group, and FDA's statistical review gives Study 301, the slow-titration trial, arms of 112 and 108 ³, ⁴. That report gives the improvement as 14.7 percent against 7.2 percent, with a P value of 0.036 ³. A P value is the chance of seeing a gap that large if the drug did nothing. Both figures count every randomized patient; the report carries a dropout's last score forward, and the label's figures match FDA's analysis carrying forward the starting score ⁴.

The label gives two further measures from that trial. Patients with at least a 30 percent improvement, the "responders," were 16 percent of the ziconotide group and 12 percent of the placebo group ¹. Use of non-intrathecal opioids fell by 24 percent with ziconotide and by 17 percent with placebo ¹. The label adds that the effect on pain "was variable over the time period of treatment for some patients" ¹.

Two published trials also titrated ziconotide over 5 to 6 days, and the label does not say whether they are among its three studies ⁵, ¹, ⁶. FDA's statistical review names three efficacy studies: Study 301 and two short-term trials, in malignant and nonmalignant pain, in which the applicant counted low-dose patients only and excluded one site ⁴. Studied in people: a randomized, double-blind, placebo-controlled trial published in January 2004 enrolled 111 patients aged 24 to 85 with cancer or AIDS ⁵. Their pain was refractory to conventional treatment, with a mean pain score of 50 millimeters or more ⁵. They were assigned two to one to ziconotide or placebo at 32 centers in the United States, Australia and the Netherlands ⁵.

The abstract counts an evaluable population of 68 patients on ziconotide and 40 on placebo ⁵. Mean pain scores improved 53.1 percent with ziconotide (95 percent confidence interval 44.0 to 62.2) and 18.1 percent with placebo (4.8 to 31.4) ⁵. Pain relief was moderate to complete in 52.9 percent of the ziconotide group and 17.5 percent of the placebo group ⁵. The authors concluded that ziconotide "provided clinically and statistically significant analgesia in patients with pain from cancer or AIDS" ⁵.

A second trial, published in April 2006, studied pain not caused by cancer ⁶. It gave ziconotide to 169 patients and placebo to 86, all with severe chronic nonmalignant pain "unresponsive to conventional therapy," over six days in the hospital ⁶. The mean reduction in pain score was 31.2 percent with ziconotide and 6.0 percent with placebo ⁶. The starting and maximum doses were reduced during the trial because of adverse events, shortened in the report to AEs ⁶. The authors reported "a considerable incidence of ziconotide-associated AEs due to the rapid titration and high doses administered" ⁶.

The authors of the May 2006 report compared the approaches. They wrote that slow titration "was better tolerated than in two previous controlled trials that used a faster titration to a higher mean dose" ³.

The label sets out what its trials did not cover. Its placebo-controlled comparisons cover titration periods of 5 to 6 days and of 21 days ¹. It reports no placebo-controlled pain result beyond three weeks ¹. The label says the combination with intrathecal opiates "has not been studied in placebo-controlled clinical trials and is not recommended" ¹. Safety and effectiveness in pediatric patients "have not been established" ¹.

The label reports no result for weight, metabolism, muscle or athletic performance in people ¹. Its table for the slow-schedule trial lists anorexia, the medical term for loss of appetite, in 6 percent of ziconotide patients and 2 percent on placebo ¹.

What are the side effects?

The label's boxed warning reads: "Severe psychiatric symptoms and neurological impairment may occur during treatment with PRIALT" ¹. It tells physicians to monitor all patients "frequently for evidence of cognitive impairment, hallucinations, or changes in mood or consciousness" ¹. Cognitive impairment is trouble with thinking, memory or speech.

The safety figures come from 1,254 adults who received ziconotide by continuous intrathecal infusion in trials of acute and severe chronic pain ¹. Treatment lasted a mean of 193 days, and 173 patients, 14 percent, were treated for at least a year ¹. The most frequent reactions, each in 25 percent of patients or more, were dizziness, nausea, confusional state and nystagmus, an involuntary movement of the eyes ¹.

Among patients treated with ziconotide, hallucinations were reported in 12 percent, paranoid reactions in 3 percent, and hostility and delirium in 2 percent each ¹. The label says ziconotide "may cause or worsen depression with the risk of suicide in susceptible patients" ¹. In placebo-controlled trials, suicide, suicide attempts and suicidal thoughts occurred at 0.27 per patient-year with ziconotide and 0.10 with placebo ¹. A patient-year is one patient followed for one year.

Confusion was reported in 33 percent of patients, memory impairment in 22 percent and speech disorder in 14 percent ¹. The label says cognitive impairment "may appear gradually after several weeks of treatment," and that the effects "are generally reversible within 2 weeks after drug discontinuation" ¹. Confusion was more common in older patients: 42 percent of those 65 and over, against 29 percent of those younger ¹.

The slow-schedule trial shows the rates against placebo ¹. Any adverse event was reported by 93 percent of the 112 ziconotide patients and 82 percent of the 108 placebo patients ¹. Dizziness affected 46 percent against 13 percent, nausea 40 against 29, and confusional state 15 against 5 ¹. Ataxia, a loss of coordination, affected 14 percent against 1 percent, and urinary retention 9 percent against none ¹. The May 2006 report says discontinuation rates for adverse events "were comparable for both groups" ³.

The route carries its own risk: meningitis, an infection of the membranes around the brain and spinal cord. The label reports it in 3 percent of the ziconotide group, 40 patients, and 1 percent of the placebo group, 1 case ¹. The label gives these rates for its clinical trials as a whole, with internal or external pumps, and does not give the placebo group's size ¹. The label says the risk "was particularly high in patients with external microinfusion devices and catheters, occurring in 38 out of 41 patients (93%), 37 of whom received PRIALT and one who received placebo" ¹.

Other warnings concern consciousness and muscle. Patients "have become unresponsive or stuporous," a state of deep unresponsiveness, with an incidence of 2 percent in trials ¹. In clinical studies, 40 percent of patients had creatine kinase, an enzyme found in muscle, above the normal range ¹. In 11 percent it exceeded three times the upper limit ¹. The label reports one case of symptomatic muscle disease and two of acute kidney failure with rhabdomyolysis, a breakdown of muscle ¹.

The label contraindicates Prialt, meaning it must not be used, in three groups ¹. They are patients with "a known hypersensitivity to ziconotide or any of its formulation components," patients with "a pre-existing history of psychosis," and patients with "any other concomitant treatment or medical condition that would render intrathecal administration hazardous" ¹. Its examples of the last are infection at the infusion site, "uncontrolled bleeding diathesis," a bleeding disorder that is not under control, and "spinal canal obstruction that impairs circulation of CSF," the cerebrospinal fluid ¹. The label also states: "There is no known antidote to ziconotide" ¹.

It tells physicians to caution patients against "operating machinery or driving a motor vehicle" ¹. Drugs that depress the central nervous system, the brain and spinal cord, may be associated with more dizziness and confusion ¹. In pregnancy, the label says the available reports "are insufficient to identify a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes" ¹. For breastfeeding, there are "no data on the presence of ziconotide in either human or animal milk" ¹.

In sport

Ziconotide is not named on WADA's 2026 Prohibited List, and neither is its class, N-type calcium channel antagonists ⁷. WADA is the World Anti-Doping Agency. Section S7 of its list, Narcotics, prohibits thirteen named narcotics in competition, morphine, oxycodone and tramadol among them ⁷. Ziconotide is not one of the thirteen ⁷. The list's rule on infusions, M2.2, prohibits "Intravenous infusions and/or injections of more than a total of 100 mL per 12-hour period except for those legitimately received in the course of hospital treatments, surgical procedures or clinical diagnostic investigations" ⁷.

What JumpstartMD offers

JumpstartMD does not prescribe ziconotide. Our peptide library covers it so you have the facts on its FDA status and the evidence, current as of November 10, 2026.

Ready to talk?

Book FREE Consultation

Share your details and a JumpstartMD team member will reach out shortly. Or call 408.478.3496 for your free, no-obligation consultation.

Share your details and a JumpstartMD team member will reach out when we open.

Disclaimer

Compounded medications are not FDA-approved, and FDA does not review their safety, effectiveness, or quality before they are marketed. A licensed clinician decides after an evaluation whether a peptide is appropriate for you, and not every patient will qualify.