title: Intrathecal gabapentin to treat chronic intractable noncancer pain.
abstract: BACKGROUND
  Oral gabapentin is approved as an anticonvulsant medication and to treat postherpetic neuralgia. Its nonopioid properties and presumed spinal site of analgesic action made the study on intrathecal gabapentin attractive to establish the minimum effective dose for a later, pivotal trial.
  
  
  METHODS
  The authors examined the safety and efficacy of intrathecal gabapentin in a randomized, blinded, placebo-controlled, multicenter trial in a heterogeneous cohort of candidates with chronic pain for intrathecal drug therapy.
  
  
  RESULTS
  Patients (N = 170) were randomized to receive continuous intrathecal gabapentin (0 [placebo], 1, 6, or 30 mg/day) during 22 days of blinded treatment after implantation of a permanent drug delivery system. The highest dose, 30 mg/day, was selected to maintain a safety margin below the 100-mg/day dose that was explored in a phase 1 study. The authors found no statistically significant difference in the primary outcome measure, which was the numerical pain rating scale and response rate after 3 weeks, for any dose versus placebo. Physical functioning, quality of life, and emotional functioning also revealed no differences. Small, nonsignificant changes occurred in opioid medication use. The most frequent device-related adverse events were transient postimplant (lumbar puncture) headache, pain, and nausea. The most frequent gabapentin-related adverse events were nausea, somnolence, headache, dizziness, fatigue, and peripheral edema.
  
  
  CONCLUSIONS
  Twenty-two days of intrathecal gabapentin did not demonstrate statistically significant or clinically meaningful analgesic effects. The study sponsor has no current plans for further studies. Drug-related adverse events were similar to those for oral gabapentin. Most device-related adverse events resulted from the implant surgery or anesthesia.
authors.affiliation: Center for Clinical Research, LLC, Carolinas Pain Institute PA, Winston-Salem, North Carolina, USA.
authors.forename: Richard
authors.initials: R
authors.lastname: Rauck
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Coffey
authors.forename: David M
authors.initials: DM
authors.lastname: Schultz
authors.forename: Mark S
authors.initials: MS
authors.lastname: Wallace
authors.forename: Lynn R
authors.initials: LR
authors.lastname: Webster
authors.forename: Sally E
authors.initials: SE
authors.lastname: McCarville
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Grigsby
authors.forename: Linda M
authors.initials: LM
authors.lastname: Page
mesh_terms: D000328:Adult; D000368:Aged; D000588:Amines / Q000008:administration & dosage* / Q000009:adverse effects; D000700:Analgesics / Q000008:administration & dosage*; D059350:Chronic Pain / Q000188:drug therapy*; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage* / Q000009:adverse effects; D005260:Female; D000077206:Gabapentin; D006801:Humans; D007278:Injections, Spinal; D008297:Male; D008875:Middle Aged; D010148:Intractable Pain / Q000188:drug therapy*; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage* / Q000009:adverse effects
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin