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    ABSTRACT: Before long-term intrathecal analgesic therapy is initiated, patients often undergo a spinal analgesia trial. Ziconotide is a nonopioid intrathecal analgesic used to manage severe chronic pain, and a variety of methods have been used to trial ziconotide. The purpose of this review is to compare and discuss the different methods of ziconotide trialing. Various databases (i.e., PubMed, Excerpta Medica, Cumulative Index to Nursing and Allied Health Literature, Biological Abstracts, Cochrane Database of Systematic Reviews, EMBASE, International Pharmaceutical Abstracts, and Google Scholar) and association meeting abstracts were searched with the use of the terms ziconotide, Prialt, trial, and trialing. In addition, a search was conducted for abstracts/posters presented at a variety of association meetings. Nine sources, including one expert opinion piece, were identified. Three methods of ziconotide trialing were discovered: continuous infusion, limited-duration infusion, and bolus injection. Results indicate that patients often achieve analgesia during trialing, regardless of the trialing method. Adverse events reported during ziconotide trialing studies were similar to those reported during ziconotide clinical trials. Preliminary evidence suggests that both effectiveness and safety may be dose-related. In 3 studies the value of ziconotide trialing in predicting long-term patient response to ziconotide therapy was investigated; however, the results were preliminary. The expert opinion piece from 2008 recommended trialing ziconotide via continuous infusion, using a starting dose of 1.2 mcg/d and dose increases of 1.2 mcg/d every 12 to 24 hours, for up to 3 days; the trial may be extended in some cases. Given the small samples size and lack of controlled ziconotide trialing studies, it is currently not possible to determine the relative safety and effectiveness of different methods of ziconotide trialing, nor is it possible to determine if trialing is predictive of patient response to long-term ziconotide therapy. All 3 methods of ziconotide trialing appear to be viable options, and no method can be considered superior on the basis of the evidence presented in this review. Controlled studies comparing ziconotide trialing methods may be warranted.
    Full-text · Article · Nov 2009 · Pain physician
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    ABSTRACT: To describe the pharmacology, efficacy, and safety of ziconotide for treatment of severe chronic pain in patients who are candidates for intrathecal therapy. A PubMed/MEDLINE search (1966-June 2006) was conducted using the terms ziconotide, Prialt, and SNX-111. Manufacturer-provided data, the Food and Drug Administration medical review of ziconotide, and abstracts presented at American Pain Society meetings (2001-2006) were also reviewed. Human studies evaluating the efficacy and safety of ziconotide for the treatment of chronic pain were considered. Animal data were excluded. Ziconotide is the first and only neuronal-type (N-type) calcium-channel blocker. Ziconotide must be administered intrathecally via continuous infusion. A programmable implanted variable-rate microinfusion device, or an external microinfusion device and catheter must be utilized. In double-blind, placebo-controlled studies, ziconotide significantly improved patient perception of pain from baseline to the end of the study periods, which ranged from 11 to 21 days. Patients enrolled in clinical trials were intolerant of or refractory to other treatment modalities. There have been no studies that directly compared ziconotide with other intrathecal or systemic analgesics. Key ziconotide-related adverse events are neuropsychiatric, including depression, cognitive impairment, and hallucinations; depressed levels of consciousness; and elevation of creatine kinase levels. Ziconotide is also associated with a risk of meningitis due to possible contamination of the microinfusion device. Ziconotide is a therapeutic option for treatment of severe chronic pain in patients who have exhausted all other agents, including intrathecal morphine, and for whom the potential benefit outweighs the risks of serious neuropsychiatric adverse effects and of having an implanted device. Further studies are needed to determine the comparative efficacy of ziconotide and other pain therapies.
    Full-text · Article · Jul 2006 · Annals of Pharmacotherapy
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    ABSTRACT: 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). In several clinical studies morphine dosages could be substituted by ziconotide. The drug has a lag-time for the onset and offset of analgesia and adverse effects. Initial doses should therefore be low (2.4 microg/day) and titrated slowly (increasing up to a maximum of 21.6 microg/day in increases of 2.4 microg/day no more than twice weekly). The gradual increase in dose helps to reduce the incidence and severity of adverse events which affect primarily the central nervous system (e.g. dizziness, nausea, confusion). Ziconotide maintains its analgesic efficacy over months and does not cause tolerance, dependence or respiratory depression. Following intrathecal infusion ziconotide is distributed within the cerebral spinal fluid (CSF) where its clearance (0.38 ml/min) corresponds to the rate of turnover of the CSF. Negligible amounts of ziconotide are present in the systemic circulation where it is rapidly degraded by proteolysis. In conclusion, ziconotide is a new and valuable alternative analgesic for the acute and long-term treatment of severe pain, especially in patients refractory to opioids.
    No preview · Article · Oct 2006 · International journal of clinical pharmacology and therapeutics
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