Prialt (Ziconotide)
Intrathecal analgesic for severe chronic pain
Prialt (ziconotide) is a non-opioid analgesic administered directly into the spinal fluid to treat severe, chronic pain in adults. It is derived from a peptide found in the venom of the marine cone snail Conus magus and works by blocking N-type calcium channels in the spinal cord. Prialt is reserved for patients who have not responded to other pain management therapies and requires administration through an intrathecal infusion pump by a specialist physician.
Quick Facts: Prialt
Key Takeaways
- Prialt (ziconotide) is a non-opioid intrathecal analgesic for severe chronic pain that has not responded to other treatments, including systemic opioids.
- It works by a unique mechanism — blocking N-type calcium channels in the spinal cord — and does not cause opioid-type dependence or respiratory depression.
- Administration requires an intrathecal infusion pump (implanted or external) and must be managed by an experienced specialist physician.
- Common side effects include confusion, dizziness, nausea, and drowsiness; serious risks include psychiatric symptoms, meningitis, and rhabdomyolysis.
- Dosing starts very low (2.4 micrograms/day) and is titrated slowly, with a maximum of 21.6 micrograms/day, to minimize neurological adverse effects.
What Is Prialt and What Is It Used For?
Quick Answer: Prialt (ziconotide) is a prescription-only, non-opioid analgesic used for the treatment of severe, chronic pain in adults. It is given by continuous intrathecal infusion — meaning directly into the fluid surrounding the spinal cord and brain — and is reserved for patients who need this specialized route of pain relief.
Prialt contains the active substance ziconotide, a synthetic version of a naturally occurring peptide called omega-conotoxin MVIIA. This peptide is found in the venom of the marine cone snail Conus magus, a predatory sea snail native to the Indo-Pacific region. The discovery of ziconotide represents one of the most significant examples of marine-derived pharmacology, demonstrating how compounds evolved by venomous animals for predation can be harnessed for therapeutic benefit in humans.
Ziconotide belongs to a distinct class of analgesics that works through a completely different mechanism from opioids, non-steroidal anti-inflammatory drugs (NSAIDs), or other conventional pain medications. By selectively blocking N-type voltage-sensitive calcium channels (specifically Cav2.2 channels) on the presynaptic nerve terminals in the dorsal horn of the spinal cord, ziconotide prevents the release of excitatory neurotransmitters involved in nociceptive (pain) signaling. This targeted action at the spinal level means that pain signals are interrupted before they reach the brain.
The clinical indications for Prialt are narrow and specific. It is approved for the management of severe, chronic pain in adult patients who require intrathecal analgesia. In practice, this means patients with intractable pain — often due to conditions such as advanced cancer, failed back surgery syndrome, complex regional pain syndrome, or other neuropathic pain conditions — who have not achieved adequate pain relief from systemic therapies including oral or transdermal opioids, adjuvant medications, nerve blocks, or other interventional procedures.
Because ziconotide does not cross the blood–brain barrier in clinically meaningful amounts when given systemically, it must be delivered directly into the intrathecal space. This is accomplished using a programmable infusion pump, which can be either surgically implanted in the abdominal wall or worn externally in a belt-mounted pouch. The choice of pump depends on the anticipated duration of treatment, patient anatomy, and clinical considerations discussed between the patient and the treating physician.
What Should You Know Before Taking Prialt?
Quick Answer: Prialt must not be used if you are allergic to ziconotide or if you are receiving intrathecal chemotherapy. Important warnings relate to psychiatric effects (including depression and suicidal thoughts), infection risk from the catheter system, meningitis, and elevated creatine kinase levels. Tell your doctor about all other medications you take.
Contraindications
There are absolute contraindications that prevent the use of Prialt. You must not receive this medicine if you have a known allergy (hypersensitivity) to ziconotide or to any of the excipients in the formulation, which include methionine, sodium chloride, hydrochloric acid, sodium hydroxide, and water for injections. Additionally, Prialt is strictly contraindicated in patients who are simultaneously receiving any cancer chemotherapy agent by the intrathecal route, as the combination could lead to unpredictable and potentially dangerous pharmacological interactions within the cerebrospinal fluid.
Warnings and Precautions
Before and during treatment with Prialt, several important warnings and precautions should be discussed with your healthcare provider. The long-term effects of ziconotide therapy are not yet fully characterized, and the possibility of toxic effects on spinal cord tissue has not been entirely ruled out. Your doctor may therefore recommend periodic monitoring during prolonged treatment.
Patients with severe chronic pain are at higher risk of suicide and suicidal behavior compared to the general population. Prialt may also cause or worsen depression in individuals who are already vulnerable. If you have a history of depression or psychiatric illness, inform your doctor before starting treatment. Seek immediate medical attention if you experience worsening depression, unusual changes in mood, or thoughts of self-harm after beginning Prialt therapy.
Infection monitoring: If you receive Prialt through an external pump system, it is essential to inspect the catheter insertion site daily for signs of infection. Redness, swelling, pain, warmth, or discharge around the catheter site should be reported to your healthcare team immediately. Even tenderness without visible signs of infection may indicate an early infectious process and warrants prompt medical evaluation.
Meningitis risk: Symptoms of meningitis — including high fever, severe headache, stiff neck, fatigue, confusion, nausea, vomiting, and occasional seizures — require immediate medical attention. Both infectious and aseptic meningitis have been reported with intrathecal infusion systems.
Cognitive and neurological effects: Prialt can affect thinking, mood, and memory. If you notice changes in your mental clarity, ability to concentrate, or emotional state, inform your doctor promptly. These effects may necessitate dose reduction or discontinuation of treatment.
Creatine kinase elevation: Ziconotide may increase blood levels of the enzyme creatine kinase (CK). While this is usually asymptomatic, your doctor will likely monitor CK levels during treatment. Report any unexplained muscle pain, tenderness, or weakness, as these could indicate rhabdomyolysis — a serious condition involving muscle fiber breakdown that can potentially damage the kidneys.
Drowsiness and reduced consciousness: Prialt can cause significant drowsiness and reduced awareness of surroundings. If this occurs, it may be necessary to adjust your dose or stop treatment. Do not drive or operate machinery if you feel drowsy or confused.
Although rare, severe allergic reactions (anaphylaxis) can occur. Seek emergency medical help immediately if you experience sudden wheezing, difficulty breathing, chest pain, swelling of the eyelids, face, or lips, widespread rash, or itching after receiving Prialt.
Pregnancy and Breastfeeding
Prialt is not recommended during pregnancy. There are no adequate clinical data on the use of ziconotide in pregnant women. Animal reproductive studies have shown adverse effects, and the potential risk to the human fetus is unknown. Women of childbearing potential should use effective contraception during treatment with Prialt.
It is not known whether ziconotide is excreted in human breast milk. A decision must be made whether to discontinue breastfeeding or to discontinue Prialt therapy, taking into account the importance of the medicine to the mother. Discuss the risks and benefits with your healthcare provider if you are breastfeeding or plan to breastfeed.
Children and Adolescents
Prialt is not recommended for use in children and adolescents under 18 years of age. There is insufficient data on safety and efficacy in this age group, and the potential effects on the developing nervous system have not been adequately studied.
How Does Prialt Interact with Other Drugs?
Quick Answer: Prialt is contraindicated with intrathecal chemotherapy. It may interact with CNS depressants (causing excessive drowsiness), intrathecal opioids, and other medications given into the spinal fluid. Always inform your doctor about all medicines you are taking.
Drug interactions with ziconotide have not been studied as extensively as with many oral medications, partly because of its intrathecal route of administration and its peptide nature (it is not metabolized by cytochrome P450 enzymes). However, several clinically significant interactions have been identified or are theoretically possible based on the pharmacological profile of the drug.
Major Interactions
The most critical interaction involves the concurrent use of intrathecal chemotherapy agents. This combination is absolutely contraindicated. Intrathecal chemotherapy drugs and ziconotide could interact unpredictably within the cerebrospinal fluid, potentially altering the pharmacokinetics or toxicity profile of either agent.
Moderate Interactions
Ziconotide may enhance the sedative effects of other central nervous system (CNS) depressants. When Prialt is used alongside the following medications, increased drowsiness and cognitive impairment may occur, and careful monitoring is recommended:
| Drug | Interaction Type | Clinical Effect | Recommendation |
|---|---|---|---|
| Intrathecal chemotherapy | Contraindicated | Unpredictable CSF interactions | Do not combine |
| Morphine (intrathecal) | Pharmacodynamic | Additive CNS depression | Monitor closely; dose adjustment may be needed |
| Baclofen (intrathecal) | Pharmacodynamic | Increased drowsiness and confusion | Monitor neurological status |
| Clonidine | Pharmacodynamic | Enhanced hypotension and sedation | Monitor blood pressure and consciousness |
| Bupivacaine (intrathecal) | Pharmacodynamic | Additive neurological effects | Careful dose titration |
| Propofol | Pharmacodynamic | Enhanced CNS depression during anesthesia | Inform anesthesiologist |
Minor Interactions
Because ziconotide is a peptide that is degraded by ubiquitous peptidases in the body and is not metabolized by liver enzymes, it has a low potential for pharmacokinetic drug interactions with oral medications. However, any medication that causes drowsiness or cognitive impairment (including benzodiazepines, antihistamines, and alcohol) may have additive effects when combined with Prialt. Patients should be counseled about these potential interactions and advised to exercise caution.
What Is the Correct Dosage of Prialt?
Quick Answer: Prialt treatment is started at 2.4 micrograms/day by continuous intrathecal infusion. The dose is increased slowly (no more than 2.4 mcg/day at intervals of at least 1–2 days) up to a maximum of 21.6 micrograms/day, based on pain relief and tolerability.
Prialt must only be prescribed and managed by physicians experienced in intrathecal drug delivery and the use of implanted or external infusion pumps. Dosing requires careful, individualized titration because the therapeutic window is relatively narrow and neurological side effects are dose-dependent.
Adults
Standard Adult Dosing Protocol
- Starting dose: 2.4 micrograms/day (0.1 micrograms/hour) as a continuous intrathecal infusion
- Titration: May increase by up to 2.4 micrograms/day, with dose adjustments no more frequently than every 1–2 days
- Maximum dose: 21.6 micrograms/day (0.9 micrograms/hour)
- Dose reduction: If side effects become intolerable, the dose may be reduced or infusion temporarily stopped
The infusion is delivered continuously through a programmable pump. External pumps (such as the CADD-Micro) can be used for short-term therapy or during the initial assessment period, while implanted pumps (such as the Medtronic SynchroMed) are preferred for long-term treatment. The choice of pump affects the minimum concentration of the ziconotide solution: at least 5 micrograms/mL for external pumps and at least 25 micrograms/mL for internal pumps.
| Parameter | External Pump | Implanted Pump |
|---|---|---|
| Minimum concentration | 5 mcg/mL | 25 mcg/mL |
| Starting dose | 2.4 mcg/day | 2.4 mcg/day |
| Maximum dose | 21.6 mcg/day | 21.6 mcg/day |
| Stability at 37°C | 21 days (room temp) | 14 days (naive pump) / 60 days (primed) |
| Refill interval | Per clinical need | 14 days initially, then 60 days |
Children
Prialt is not recommended for use in children and adolescents under 18 years of age. There is no established pediatric dosing protocol, and the safety and efficacy of ziconotide have not been studied in this population.
Elderly Patients
No specific dose adjustment is required for elderly patients based on age alone. However, older patients may be more susceptible to the cognitive and neurological side effects of ziconotide, including confusion, drowsiness, and gait disturbance. Clinicians should use particular caution when titrating the dose in elderly patients, with potentially smaller increments and longer intervals between dose adjustments.
Missed Dose
Because Prialt is delivered as a continuous infusion, a “missed dose” would indicate a pump malfunction or interruption in the infusion system. If the infusion stops unexpectedly, contact your healthcare provider or the clinic managing your pump immediately. Unlike opioids, abrupt discontinuation of ziconotide does not cause a withdrawal syndrome, but pain will return as the drug is cleared from the cerebrospinal fluid.
Overdose
If you receive more Prialt than your doctor planned, you may experience an exaggeration of the known side effects. Symptoms of overdose can include severe confusion, difficulty speaking or finding words, marked tremor, pronounced dizziness, excessive drowsiness, nausea, and vomiting. There is no specific antidote for ziconotide overdose. Treatment is supportive: the infusion should be stopped or the dose reduced, and medical observation should be continued until symptoms resolve. Contact your doctor or hospital immediately if you suspect an overdose.
What Are the Side Effects of Prialt?
Quick Answer: The most common side effects of Prialt are neurological: confusion, dizziness, blurred vision, headache, nystagmus, memory impairment, nausea, vomiting, weakness, and drowsiness. Serious but less common effects include meningitis, seizures, suicidal ideation, rhabdomyolysis, and coma.
Like all medicines, Prialt can cause side effects, although not everybody gets them. The side effect profile of ziconotide is predominantly neurological, reflecting the drug's action on calcium channels in the central nervous system. Many side effects are dose-dependent and may improve with dose reduction. Below is a comprehensive breakdown of reported adverse effects organized by frequency.
Seek urgent medical care if you experience: signs of meningitis (severe headache, stiff neck, fever, confusion, light sensitivity); seizures; thoughts of self-harm or suicide; dark brown urine with muscle pain (rhabdomyolysis); loss of consciousness or coma; or signs of a severe allergic reaction (sudden breathing difficulty, chest pain, facial swelling, widespread rash).
Serious Side Effects
Require immediate medical attention
- Meningitis — inflammation of the membranes around the brain and spinal cord (up to 1 in 100)
- Seizures (convulsions) — uncontrolled body shaking and possible loss of consciousness (up to 1 in 100)
- Suicidal thoughts or suicide attempts (up to 1 in 100)
- Rhabdomyolysis — breakdown of muscle fibers potentially causing kidney damage (up to 1 in 100)
- Coma — profound unconsciousness (up to 1 in 100)
- Anaphylactic reaction — severe, life-threatening allergic reaction (frequency unknown)
Very Common
May affect more than 1 in 10 people
- Confusion
- Dizziness
- Blurred vision
- Headache
- Nystagmus (rapid involuntary eye movements)
- Memory impairment (forgetfulness)
- Nausea
- Vomiting
- General weakness (asthenia)
- Drowsiness (somnolence)
Common
May affect up to 1 in 10 people
- Decreased appetite, anxiety, hallucinations, insomnia, restlessness
- Depression or worsened depression, nervousness, mood swings, irritability, paranoia
- Disorientation, abnormal thinking, confusion (worsened), cognitive difficulty
- Reduced or absent reflexes, speech problems, slurred speech
- Impaired balance and coordination, burning sensation, abnormal sensations
- Sedation, difficulty concentrating, altered smell or taste, tremor, tingling
- Double vision, visual disturbances, light sensitivity, tinnitus, vertigo
- Low blood pressure, shortness of breath, dry mouth, abdominal pain
- Diarrhea, constipation, sweating, itching
- Muscle weakness, muscle spasms, cramps, muscle or joint pain
- Difficulty urinating, urinary retention, feeling of nervousness
- Falls, pain (or worsened pain), fatigue, feeling cold
- Swelling of face, legs, or feet, chest pain, weight loss
Uncommon
May affect up to 1 in 100 people
- Blood infection (sepsis), delirium, psychotic disorder
- Thought disorder, abnormal dreams, loss of consciousness, stupor
- Stroke, encephalopathy (brain disease), aggression
- Abnormal heart rhythm, breathing difficulties, indigestion
- Rash, muscle inflammation, back pain, muscle twitching, neck pain
- Acute kidney failure, abnormal ECG, elevated body temperature
- Difficulty walking
If you experience any side effects, including those not listed above, talk to your doctor or pharmacist. You can also report suspected side effects directly to your national pharmacovigilance authority (e.g., the FDA MedWatch program in the US, the Yellow Card Scheme in the UK, or the EMA in Europe). By reporting side effects, you help improve the safety information available for this medicine.
How Should You Store Prialt?
Quick Answer: Prialt must be stored in a refrigerator at 2–8°C, protected from light, and must not be frozen. Once opened or diluted, it should be used promptly. The solution remains stable for up to 60 days at 37°C in an infusion pump.
Proper storage of Prialt is essential to maintain the stability and efficacy of the medication. As a peptide-based drug, ziconotide is sensitive to temperature extremes, light exposure, and oxidative degradation. The following storage guidelines should be followed:
- Unopened vials: Store in a refrigerator at 2–8°C (36–46°F). Do not freeze. Keep the vial in the outer carton to protect from light.
- In-use stability: Chemical and physical stability has been demonstrated for 60 days at 37°C when placed in a primed infusion pump.
- Diluted solution: If Prialt is diluted, it should be transferred to the infusion pump immediately. If not used immediately, the diluted solution should generally be used within 24 hours when stored at 2–8°C, unless prepared under validated aseptic conditions.
- Visual inspection: Do not use this medicine if you notice any discoloration, cloudiness, or visible particles in the solution. Prialt should appear as a clear, colorless liquid.
- Expiry date: Do not use after the expiration date printed on the label and carton. The expiry date refers to the last day of the stated month.
Keep this medicine out of the sight and reach of children. Your healthcare team will handle the storage and preparation of Prialt in most circumstances, as it is administered in a clinical setting or through a professionally managed pump system.
What Does Prialt Contain?
Quick Answer: Each milliliter of Prialt solution contains 25 micrograms of ziconotide (as acetate). A 20 mL vial contains 500 micrograms total. The inactive ingredients are methionine, sodium chloride, water for injections, hydrochloric acid, and sodium hydroxide.
Active Ingredient
The active substance is ziconotide (as the acetate salt). Ziconotide is a 25-amino-acid peptide with a molecular weight of approximately 2,639 daltons. It is a synthetic equivalent of omega-conotoxin MVIIA, originally isolated from the venom of Conus magus. The peptide has three disulfide bonds that maintain its three-dimensional structure, which is critical for its biological activity at N-type calcium channels.
Inactive Ingredients (Excipients)
- L-Methionine: An amino acid used as an antioxidant to protect ziconotide from oxidative degradation
- Sodium chloride: Provides isotonicity to the solution
- Water for injections: The solvent base
- Hydrochloric acid: pH adjustment
- Sodium hydroxide: pH adjustment
The sodium content is less than 1 mmol (23 mg) per maximum recommended daily intrathecal dose (21.6 micrograms/day), meaning Prialt is essentially sodium-free.
Pharmaceutical Form and Packaging
Prialt is supplied as a clear, colorless solution for infusion in single-use glass vials. Each carton contains one 20 mL vial. The vials are for single use only; any unused solution should be discarded according to local pharmaceutical waste regulations.
Frequently Asked Questions About Prialt
Prialt (ziconotide) is used for the treatment of severe, chronic pain in adults who require intrathecal analgesia. It is delivered directly into the spinal fluid via an implanted or external infusion pump. Prialt is typically reserved for patients whose pain has not responded adequately to other treatments, including systemic analgesics, adjunctive therapies, or intrathecal morphine. Common underlying conditions include cancer pain, failed back surgery syndrome, and complex regional pain syndrome.
Unlike opioids, which bind to mu-opioid receptors in the brain and spinal cord, Prialt (ziconotide) works by blocking N-type voltage-sensitive calcium channels on nerve cells in the spinal cord dorsal horn. This prevents the release of neurotransmitters involved in pain signaling. Because ziconotide acts through a completely different mechanism, it does not cause opioid-type side effects such as respiratory depression, physical dependence, tolerance development, or constipation. This makes it a valuable alternative for patients who cannot tolerate or have not responded to opioid therapy.
The most common side effects of Prialt (affecting more than 1 in 10 patients) are predominantly neurological and include confusion, dizziness, blurred vision, headache, nystagmus (rapid involuntary eye movements), memory impairment, nausea, vomiting, general weakness, and drowsiness. These side effects are often dose-related and may improve when the dose is reduced. Your doctor will start with a very low dose and increase it gradually to help minimize these effects.
Prialt must never be combined with intrathecal chemotherapy agents. When used alongside other intrathecal drugs such as baclofen, clonidine, bupivacaine, or morphine, additional monitoring may be needed due to the potential for additive central nervous system depression. Systemic (oral or injectable) pain medications may be continued during Prialt therapy, but any CNS depressant (including benzodiazepines, antihistamines, or alcohol) may increase drowsiness. Always inform your healthcare provider about all medications you are taking before starting Prialt.
No, unlike opioids, ziconotide does not cause physical dependence or a withdrawal syndrome when discontinued. If the infusion is stopped, pain will gradually return as the drug is cleared from the cerebrospinal fluid, but you will not experience the withdrawal symptoms (such as sweating, anxiety, muscle aches, or gastrointestinal upset) that are associated with stopping opioid medications. However, if you were previously taking intrathecal opioids before starting Prialt, your doctor will have tapered those medications appropriately to avoid opioid withdrawal.
Prialt is given as a continuous, slow intrathecal infusion using either an implanted programmable pump or an external pump. For implanted pumps, the first refill typically occurs after 14 days. Once the pump has been primed with the drug, subsequent refills are generally performed every 60 days. External pumps are refilled as clinically needed. Your pain management team will schedule regular appointments for pump refills and monitoring. It is important to attend these appointments to ensure uninterrupted pain relief and to check for any complications.
References
- European Medicines Agency (EMA). Prialt – Summary of Product Characteristics. Last updated 2024. Available at: EMA – Prialt EPAR.
- Staats PS, Yearwood T, Charapata SG, et al. Intrathecal ziconotide in the treatment of refractory pain in patients with cancer or AIDS: a randomized controlled trial. JAMA. 2004;291(1):63–70. doi:10.1001/jama.291.1.63.
- Rauck RL, Wallace MS, Leong MS, et al. A randomized, double-blind, placebo-controlled study of intrathecal ziconotide in adults with severe chronic pain. J Pain Symptom Manage. 2006;31(5):393–406.
- Deer TR, Pope JE, Hayek SM, et al. The Polyanalgesic Consensus Conference (PACC): Recommendations on intrathecal drug infusion systems best practices and guidelines. Neuromodulation. 2017;20(2):96–132.
- World Health Organization (WHO). WHO Guidelines for the Pharmacological and Radiotherapeutic Management of Cancer Pain in Adults and Adolescents. Geneva: WHO; 2018.
- National Institute for Health and Care Excellence (NICE). Intrathecal drug delivery systems for chronic pain. Technology Appraisal TA303. 2020.
- McGivern JG. Ziconotide: a review of its pharmacology and use in the treatment of pain. Neuropsychiatr Dis Treat. 2007;3(1):69–85.
- Pope JE, Deer TR. Ziconotide: a clinical update and pharmacologic review. Expert Opin Pharmacother. 2013;14(7):957–966.
Editorial Team
This article was written by the iMedic Medical Editorial Team, comprising licensed specialist physicians in pain medicine, anesthesiology, and clinical pharmacology. All content is reviewed according to international medical standards, including guidelines from the European Medicines Agency (EMA), the U.S. Food and Drug Administration (FDA), the World Health Organization (WHO), and the National Institute for Health and Care Excellence (NICE).
Written by physicians with expertise in pain medicine and neuropharmacology. All medical claims are supported by peer-reviewed evidence at the highest available quality level.
Reviewed by the iMedic Medical Review Board, an independent panel of specialists who verify accuracy, completeness, and adherence to current clinical guidelines.
Content follows the GRADE evidence framework. No commercial funding or pharmaceutical industry influence. Full editorial independence maintained.
This article is reviewed regularly and updated when new evidence, regulatory changes, or guideline revisions become available. Last fact-check: January 2026.