Ziconotide (CI 1009, SNX 111), the synthetic form of the cone snail peptide &ohgr;-cenotoxin M-VII-A, is a neurone-specific calcium channel blocker that is being developed as an analgesic agent by Neurex Corporation (a subsidiary of Elan Corporation). There are positive first phase III trial results regarding the selectivity and effectiveness of ziconotide in the treatment of severe neurogenic pain including post-herpetic neuralgia (shingles), phantom limb syndrome and reflex sympathetic dystrophy. Ziconotide has shown to be effective in alleviating severe neurogenic pain in patients with HIV who had failed opiate treatment. Ziconotide has completed a second phase III clinical trial for the treatment of intractable, noncancer pain as well as cancer pain in patients who demonstrated a nonresponse or intolerance to opiate therapy. Ziconotide has entered phase II clinical trials with Neurex for the management of severe postoperative pain after major thoracic, orthopaedic and abdominal surgery. Both the epidural and intrathecal routes of administration will be investigated.Ziconotide for the treatment of chronic pain is being developed in cooperation with Medtronic using their SynchroMed® implantable pump for direct administration into the spine. Under a cost-sharing agreement, Medtronic has worldwide rights to ziconotide for spinal administration, while Neurex retains manufacturing rights and rights for further development of ziconotide as an acute analgesic agent. Warner-Lambert has licensed rights worldwide except for Japan and East Asia for use in neurological indications. Ono had rights to Neurex-discovered neurone-specific calcium channel blockers for Japan and East Asia, however this agreement was terminated.Ziconotide is undergoing phase III clinical trials with Neurex (in collaboration with Warner-Lambert) in the US and Europe for the prevention of ischaemic brain damage following stroke and severe head trauma. Phase III trials are also underway in Japan. The US FDA had put a clinical hold on ziconotide because of recumbent hypotension in a trial for the prevention of brain damage after closed head trauma and coronary artery bypass grafting, but this hold has since been lifted.