Ziconotide

Ziconotide (Prialt) is a synthetic version of ω-conotoxin MVIIA, a 25-amino-acid peptide neurotoxin derived from the marine cone snail Conus magus. It is approved by FDA and EMA as a third-line treatment for severe chronic pain in adults requiring intrathecal (IT) analgesia. It carries FDA boxed warnings for severe psychiatric and neurological adverse effects, including suicide risk, and is restricted to use with specialised intrathecal equipment. No US federal CSA scheduling was identified as of 2026-08-06; state law and other jurisdictions were not assessed.

Ziconotide is a selective, reversible, high-affinity blocker of N-type voltage-gated calcium channels (CaV2.2). By binding to the α₁B subunit, it prevents calcium influx into presynaptic nociceptive terminals in the dorsal horn of the spinal cord, thereby blocking release of multiple neurotransmitters (substance P, CGRP, glutamate) involved in pain transmission. It produces analgesia without opioid receptor involvement, mu-receptor activity, or respiratory depression. Mechanism is well-characterised — high confidence.

Approved labeled regimen

The label summary below is product-, indication-, and jurisdiction-specific; consult the full current label and a licensed clinician/pharmacist.

FDA-approved regimen:

• Intrathecal only via micro-infusion device (SynchroMed II or equivalent)

• Start: No more than 2.4 mcg/day (0.1 mcg/hour)

• Titrate: Increase by up to 2.4 mcg/day at intervals no more frequently than 2–3 times per week

• Maximum: 19.2 mcg/day (0.8 mcg/hour) by Day 21

• Device: Use with the Medtronic SynchroMed II or III infusion system per manufacturer's manual for programming, reservoir rinse, initial fill, and refill procedures

• Initial fill with naïve pump: Use undiluted 25 mcg/mL; refill within 14 days

• Subsequent refills (undiluted): at least every 84 days; (diluted): at least every 40 days

Studied regimens (not recommendations)

• Pivotal fast-titration (Staats 2004): 0.2–7.2 mcg/day with high AE rates

• Wallace 2006 slow titration: 0.1–0.9 mcg/day starting dose, showed improved tolerability — this is a consensus clinical approach, NOT the FDA label starting dose

What is not established

• Safety or efficacy by any non-IT route (IV, epidural, intranasal, subcutaneous)

• Paediatric safety and efficacy

• Long-term safety beyond 12 months in controlled studies

• Combination with IT opioids (limited data; possible synergy with morphine but must use separate pumps)

Established label risks

Boxed warning — Severe psychiatric/neurological effects (FDA):

• Severe psychiatric symptoms (psychosis, hallucinations, paranoia, mood alterations, depression, suicide)

• Cognitive impairment (confusion, memory impairment, speech disorder)

• Neurological impairment (ataxia, nystagmus, gait disturbance)

• All patients must be monitored; dose reduction or discontinuation if symptoms develop

Important warnings:

• Suicide: Cases of suicide/suicide attempt reported; evaluate for depression/suicidality before and during treatment

• Meningitis: Pump/catheter infection risk (IT delivery); meningitis requiring hospitalisation reported

• Elevated CPK: In 40% of patients; CPK monitoring recommended — rhabdomyolysis reported with higher doses

• Withdrawal: Not associated with opioid withdrawal (no opioid activity)

• US federal scheduling: No CSA scheduling was identified as of 2026-08-06; this does not assess state law or other jurisdictions. The reviewed label does not describe opioid-like dependence or tolerance.

Contraindications: Pre-existing history of psychosis; known hypersensitivity to ziconotide or any formulation component; any concomitant treatment or medical condition that would render intrathecal administration hazardous, including infection at the microinfusion injection site, uncontrolled bleeding diathesis, or spinal canal obstruction impairing CSF circulation.

Human-study signals

High AE rate in clinical trials: dizziness (50%), confusion (30%), ataxia (20%), abnormal gait (20%), memory impairment (15%), hallucinations (10–15%), vomiting (30%), somnolence (20%). Most AEs dose-dependent and improve with slow titration.

Unknowns and product-quality risks

• No data on paediatric use

• Long-term cognitive effects beyond 12 months unknown

• Effect on driving/operating machinery (assessed in label — likely impaired)

• Interaction with IT baclofen, clonidine, or other IT agents not studied

• Research chemical ω-conotoxin products (non-IT, unapproved routes) are extremely dangerous — no safety data and risk of severe toxicity

• Concomitant IT opioids: Pharmacokinetic compatibility confirmed for SynchroMed II; efficacy data limited

• CNS depressants: Additive effects with benzodiazepines, opioids, anaesthetics, alcohol

• Nephrotoxicity risk with aminoglycosides, amphotericin B, cisplatin, cyclosporine, NSAIDs (theoretical based on animal data)

• Renal impairment: No dose adjustment studied — use caution

• Elderly (>65): Higher AE rates; slower titration recommended

• Pregnancy: Category C — animal reproductive toxicity; no adequate human studies

• Lactation: Unknown if excreted in breast milk

• DEA: NOT a controlled substance — no abuse liability; common misconception corrected

• WADA: ziconotide was not identified by exact name in the 2026 Prohibited List, and this review did not identify a matching prohibited class. Route of administration and an unsupported assumption about performance effect do not themselves determine classification; athletes should verify the exact product and current status.

• The reviewed US PRIALT product is prescription-only and its labeled use requires specialist intrathecal-pump management; access rules vary elsewhere

• FDA approval of PRIALT does not by itself establish a lawful or clinically equivalent compounding pathway, and this page does not imply a REMS program

• Prior-authorisation typically required in US insurance

• Paediatric safety and efficacy entirely absent

• Long-term cognitive effects >12 months unstudied

• Optimal slow-titration protocol still debated

• Combination with IT opioids or clonidine needs controlled trials

• Carcinogenicity, mutagenicity data limited (not expected given mechanism)

• No head-to-head comparator with IT morphine as first-line therapy

• Cost-effectiveness data limited for long-term use

• Databases and registries: PubMed, DailyMed, FDA Drugs@FDA, EMA EPAR, ClinicalTrials.gov, DEA scheduling

• Search terms: Ziconotide, Prialt, SNX-111, ω-conotoxin MVIIA, 107452-89-1, intrathecal, boxed warning

• Last searched: 2026-08-06

• Inclusion emphasis: regulatory labels, pivotal trials, safety communications

1. FDA label: Prialt (ziconotide). DailyMed (updated May 2025). https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=b025d8ed-937d-4597-9ad1-0b2f6e0ee5b1

2. Staats PS, 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. PMID 14709577. DOI 10.1001/jama.291.1.63. https://pubmed.ncbi.nlm.nih.gov/14709577/

3. Wallace MS et al. (2006) Anesth Analg. Pivotal trial (slow titration). PMID

4. DrugBank DB06283. https://go.drugbank.com/drugs/DB06283

5. PubChem CID 16135415. https://pubchem.ncbi.nlm.nih.gov/compound/16135415

6. DEA Office of Diversion Control — no US federal CSA scheduling identified for ziconotide.

7. World Anti-Doping Agency. 2026 Prohibited List. https://www.wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf