title: Ziconotide Trialing by Intrathecal Bolus Injections: An Open-Label Non-Randomized Clinical Trial in Postoperative/Posttraumatic Neuropathic Pain Patients Refractory to Conventional Treatment.
abstract: OBJECTIVE
  The aim of this open-label, non-randomized, clinical trial was to evaluate the feasibility of trialing ziconotide by intrathecal bolus injections.
  
  
  METHODS
  Twenty-three patients, who had peripheral neuropathic pain refractory to pharmacological treatment and were under consideration for Spinal Cord Stimulation, received up to three ziconotide bolus injections according to a comprehensive algorithm. After a first injection of 2.5 μg, the patients progressed in the algorithm depending on the presence or absence of pain reduction and significant adverse events. A patient was considered a "responder" if experiencing pain reduction and no significant adverse event on two consecutive occasions at the same dosage.
  
  
  RESULTS
  We found a low proportion of responders (13%). However 30% of patients experienced ≥30% pain reduction on a least one injection, yielding a number needed to treat of ∼3 for clinically significant pain relief. Pain intensity changed significantly over time (0-6 h) (p = 0.047) after a mean ziconotide dose of 2.75 μg. Adverse events were as expected, and no serious adverse event occurred. We did not find any statistical association between response to Spinal Cord Stimulation and response to ziconotide.
  
  
  CONCLUSIONS
  Ziconotide bolus injection trialing seems feasible, but the proportion of responders in the present study was low. Adverse events were as expected, and no serious adverse event occurred. The predictive power of ziconotide bolus trialing remains unclear, and the pharmacological profile of ziconotide (slow tissue penetration due to high hydrophilicity) calls the rationale for bolus trialing into question.
authors: Rehabilitation Medicine, Department of Medicine and Health Sciences, Linköping University, Linköping, SE 581 85, Sweden.|Pain and Rehabilitation Centre, UHL, County Council of Östergötland, Linköping, SE 581 85, Sweden.
authors: Emmanuel
authors: E
authors: Bäckryd
authors: Rehabilitation Medicine, Department of Medicine and Health Sciences, Linköping University, Linköping, SE 581 85, Sweden.|Pain and Rehabilitation Centre, UHL, County Council of Östergötland, Linköping, SE 581 85, Sweden.
authors: Jan
authors: J
authors: Sörensen
authors: Rehabilitation Medicine, Department of Medicine and Health Sciences, Linköping University, Linköping, SE 581 85, Sweden.|Pain and Rehabilitation Centre, UHL, County Council of Östergötland, Linköping, SE 581 85, Sweden.
authors: Björn
authors: B
authors: Gerdle
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018712:Analgesics, Non-Narcotic / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D009437:Neuralgia / Q000209:etiology*; D010147:Pain Measurement; D011183:Postoperative Complications / Q000503:physiopathology*; D016896:Treatment Outcome; D020960:omega-Conotoxins / Q000008:administration & dosage*
chemical_list: D018712:Analgesics, Non-Narcotic; D020960:omega-Conotoxins; C078452:ziconotide
keywords: Bolus; intrathecal; spinal; trialing; ziconotide