Synthetic version of a toxin from the marine cone snail Conus magus. Used for severe chronic pain that does not respond to other treatments, delivered directly into the cerebrospinal fluid through an intrathecal pump.
Regulatory status
Approved (FDA / EMA)
Family
N-type calcium channel blocker (derived from a marine cone snail toxin)
FDA (U.S.): Approved (2004, Prialt) for severe chronic pain in patients who need intrathecal analgesia and do not tolerate or do not respond to other treatments.
EMA (EU): Approved (2005, Prialt) for severe chronic pain in adults who require intrathecal analgesia.
Dose
Continuous intrathecal infusion: start at 2.4 micrograms/day and titrate slowly up to a maximum of 19.2 micrograms/day (FDA label 2004 / EMA 2005).
Safety
Frequent neurological and psychiatric effects: dizziness, nausea, confusion, memory impairment, drowsiness, hallucinations and, in some cases, severe depression or suicidal thoughts (boxed warning in the US). Contraindicated with a history of psychosis. Risk of meningitis from the pump. Hospital/pain-unit use only.
Interactions
More central nervous system effects if combined with other depressants (opioids, benzodiazepines, antiepileptics).
Effect by goal · level of evidence
Refractory pain in cancer or AIDS
reducesModerateRCT (AA)in people
−53% pain vs −18%
Double-blind trial with 111 patients with pain that did not respond to strong opioids. After 5–6 days of titration, pain improved by an average of 53.1% with ziconotide vs 18.1% with placebo; half of the patients responded vs 1 in 6 with placebo.
It blocks the N-type calcium channels of the spinal cord neurons that transmit pain. As a result, less neurotransmitter is released and the pain signal reaches the brain more weakly. It is not an opioid and does not cause tolerance or dependence the way they do.
What the evidence says
In people
Refractory pain in cancer or AIDS. Double-blind trial with 111 patients with pain that did not respond to potent opioids. After 5–6 days of titration, pain improved on average by 53.1% with ziconotide versus 18.1% with placebo; half of the patients responded versus 1 in 6 with placebo. PubMed 14709577