Ziconotide is a synthetic, nonopiod, twenty-five amino acid polybasic peptide analogue of an omega-conotoxin derived from the marine snail Conus magus with analgesic activity. Ziconotide appears to block neuronal N-type voltage-sensitive calcium channels (NCCB), inhibiting transmission from pain-sensing primary nociceptors. This agent may exhibit significant analgesic activity in refractory pain.
Ziconotide is a powerful analgesic drug that has a unique mechanism of action involving potent and selective block of N-type calcium channels, which control neurotransmission at many synapses. The analgesic efficacy of ziconotide likely results from its ability to interrupt pain signaling at the level of the spinal cord. Ziconotide is a peptidic drug and has been approved for the treatment of severe chronic pain in patients only when administered by the intrathecal route. Importantly, prolonged administration of ziconotide does not lead to the development of addiction or tolerance. The current review discusses the various studies that have addressed the in vitro biochemical and electrophysiological actions of ziconotide as well as the numerous pre-clinical studies that were conducted to elucidate its antinociceptive mechanism of action in animals. In addition, this review considers the pivotal Phase 3 (and other) clinical trials that were conducted in support of ziconotide’s approval for the treatment of severe chronic pain and tries to offer some insights regarding the future discovery and development of newer analgesic drugs that would act by a similar mechanism to ziconotide but which might offer improved safety, tolerability and ease of use.
McGivern, J. G. (2007). Ziconotide: a review of its pharmacology and use in the treatment of pain. Neuropsychiatric disease and treatment, 3(1), 69.
Ziconotide is the only N-type calcium channel blocker approved by the US FDA for the treatment of chronic pain. The approved indication is for the management of severe chronic pain in patients for whom intrathecal therapy is warranted and who are intolerant of or refractory to other treatments such as systemic analgesics, adjunctive therapies or intrathecal morphine.
Williams, J. A., Day, M., & Heavner, J. E. (2008). Ziconotide: an update and review. Expert opinion on pharmacotherapy, 9(9), 1575-1583.
Worldwide a large number of patients suffer from severe chronic pain even after treatment with opioids following the 3-step analgesic ladder developed by the WHO. Intraspinal agents, including morphine, have been tried as a fourth step. However, approximately 20% of cases remain refractory. Ziconotide, an intrathecal analgesic with orphan drug status, is a novel alternative for the management of chronic intractable pain. Ziconotide is a synthetic peptide based on the toxin of the fish-hunting marine snail, Conus magus. It is the first therapeutic agent in a new pharmacological class of "topically" active analgesics that selectively target neuron-specific (N-type), voltage-gated calcium channels. Ziconotide produces potent analgesia by interruption of Ca-dependent primary afferent transmission of pain signals in the spinal cord. Ziconotide was significantly more effective than placebo in the treatment of chronic malignant (p < 0.001) and non-malignant pain (p < 0.001).
Klotz, U. (2006). Ziconotide-a novel neuron-specific calcium channel blocker for the intrathecal treatment of severe chronic pain-a short review. International Journal of Clinical Pharmacology & Therapeutics, 44(10).