For cancer and AIDS patients, 10 - 30% of pain is refractory to strong opioids, requiring intraspinal administration for pain management. Ziconotide is a selective N-type calcium channel blocker, which inhibits neurotransmitter release, and following intrathecal administration will affect primary nociceptive afferents. In 108 patients with previously unmanaged refractory pain despite the use of systemic or intrathecal opioids, in the initial titration phase, the mean Visual Analogue Scale of Pain Intensity scores improved more in the ziconotide group (53%) than the placebo group (18%). Serious adverse effects were more common in the ziconotide group (31%) than placebo group (10%) in the initial titration phase. In the 48 patients receiving ziconotide, who proceeded to the maintenance phase, the benefit of ziconotide was continued. Until a new approach with a better effectiveness/ adverse effects profile than ziconotide for refractory pain emerges, further optimisation of ziconotide for use in the treatment of refractory pain should be undertaken.
