← The ApothecaryConidaevenom peptide (ω-conotoxin MVIIA), now made syntheticallyFact-checked 24 October 2026

Toxic — not for home useCone snails are venomous predators that inject venom through a harpoon-like tooth; their conotoxins act on nerve ion channels. Ziconotide is given only through an implanted or external intrathecal pump under specialist care. Not for home use.In an emergency, call your local emergency number or poison centre.

Magician's cone snail

Conus magus

A marine cone snail whose venom contains ω-conotoxin MVIIA, a peptide that blocks N-type calcium channels in pain-signalling nerves. A synthetic copy, ziconotide (Prialt), was approved in the US in 2004 and the EU in 2005 for severe chronic pain, given only by continuous infusion into the spinal fluid. It is a hospital medicine with serious psychiatric risks, not a remedy.

What it is used for

Pain (general)
Strong
Approved for severe chronic pain needing intrathecal therapy in patients intolerant of or not helped by other treatments, including intrathecal morphine. In three placebo-controlled studies (589 patients), pain scores fell from 74 to 35 mm with ziconotide versus 61 mm on placebo in cancer/AIDS pain, and from 80 to 54 versus 72 mm in other pain; the 3-week study showed only a trend.^1,2
Nerve pain and neuralgia
Strong
One of the two short pivotal trials covered pain from causes such as nerve damage; ziconotide does not act on opioid receptors and causes no respiratory depression or dependence.^1,4

Safety

Pregnancy: Insufficient data
Breastfeeding: Insufficient data
Children: Approved for adults only.

Interactions with medicines

intrathecal chemotherapyMajorMust not be used at the same time (EMA).

Interaction checker →

Do not use if

Pre-existing history of psychosis (FDA boxed warning)
Concurrent intrathecal chemotherapy

Side effects

Boxed warning: severe psychiatric symptoms and neurological impairment; hallucinations (12%), paranoia, delirium, psychosis; may cause or worsen depression with suicide risk
Confusion, dizziness, nystagmus, memory impairment, sleepiness, blurred vision, nausea, abnormal gait, weakness
Meningitis from the infusion system (93% of patients with external devices in trials)
Raised creatine kinase

In the healing traditions

Modern pharmacology
Ziconotide (Prialt)
A synthetic copy of ω-conotoxin MVIIA. Blocks N-type (Cav2.2) voltage-gated calcium channels on spinal pain-transmitting neurons, interrupting pain signals; a non-opioid, non-NSAID analgesic given only by intrathecal pump.

Active compounds

ω-conotoxin MVIIA (ziconotide): cystine-knot peptide; reversible, high-affinity pore blocker of N-type calcium channels

History

Cone snails' intricately patterned shells made them prized by collectors long before their venom was studied. Among the many conotoxins since characterised, ω-conotoxin MVIIA from Conus magus became the most prominent clinical success: as ziconotide it was approved by the FDA in 2004 and in the EU in 2005, initially under 'exceptional circumstances' that ended in 2014.

Sources

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.