title: Topical gabapentin gel alleviates allodynia and hyperalgesia in the chronic sciatic nerve constriction injury neuropathic pain model.
abstract: Systemic gabapentin is a mainstay treatment for neuropathic pain though there are side-effects. Localized therapy may curtail such side-effects so a topical gabapentin dermal application was examined in the chronic constriction injury (CCI) model of neuropathic pain.
  
  
  
  Partial denervation CCI was achieved by rat sciatic nerve ligation. Gabapentin gel (10% w/w) was applied three times daily on the ipsilateral or contralateral plantar surface of the hind-paw, whereas in a concurrent systemic study, gabapentin was intraperitoneally administered daily (75 mg/kg) for 30 days. Tests for static- and dynamic-mechano-allodynia [paw withdrawal threshold (PWT) to von Frey filament application and latency (PWL) to light brushing], cold-allodynia [paw withdrawal duration (PWD) to acetone], heat- (PWL and PWD) and mechano-hyperalgesia (PWD to pin prick) were utilized to assess pain, whereas effects on locomotion (open field) and motor balance (rotarod and footprint analysis) were measured on days 5-30 post surgery.
  
  
  
  Topical application of gabapentin gel ipsilaterally but not contralaterally alleviated CCI-induced static- (days 10-30) and dynamic-allodynia (days 15-30), suppressed cold-allodynia (days 10-30), heat- (days 15-30) and mechano-hyperalgesia (days 5-30) indicating a local action. Systemic gabapentin exhibited similar pain profiles but was associated with motor impairment. The gabapentin gel formulation afforded desirable neuropathic pain alleviating effects devoid of unwanted systemic side-effects.
  
  
  
  These outcomes disclose an expedient pharmacological validation of the effectiveness of topical gabapentin gel against an extensive range of nociceptive stimulus modalities utilizing the CCI-induced neuropathic pain model. They also advocate further clinical studies on topical gabapentin with regard to certain neuropathic pain syndromes.
  
  
  
  Systemic gabapentin neuropathic pain management carries side-effects ostensibly preventable by localized therapy. This study validates the effectiveness potential of a topical gabapentin gel against an extensive range of nociceptive stimulus modalities utilizing the chronic constriction injury-induced neuropathic pain model.
authors.affiliation: Department of Pharmacy, Sarhad University of Science and Information Technology, Peshawar, Pakistan.|Department of Pharmacy, University of Peshawar, Pakistan.
authors.forename: M
authors.initials: M
authors.lastname: Shahid
authors.affiliation: Department of Pharmacy, University of Peshawar, Pakistan.
authors.forename: F
authors.initials: F
authors.lastname: Subhan
authors.affiliation: Department of Pharmacy, University of Peshawar, Pakistan.
authors.forename: N
authors.initials: N
authors.lastname: Ahmad
authors.affiliation: Department of Pharmacy, University of Peshawar, Pakistan.
authors.forename: G
authors.initials: G
authors.lastname: Ali
authors.affiliation: Department of Pharmacy, University of Peshawar, Pakistan.
authors.forename: S
authors.initials: S
authors.lastname: Akbar
authors.affiliation: Department of Pharmacy, University of Peshawar, Pakistan.
authors.forename: K
authors.initials: K
authors.lastname: Fawad
authors.affiliation: Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, UK.
authors.forename: R D E
authors.initials: RD
authors.lastname: Sewell
mesh_terms: D000287:Administration, Topical; D000588:Amines / Q000008:administration & dosage / Q000627:therapeutic use*; D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D003251:Constriction, Pathologic; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage / Q000627:therapeutic use*; D004195:Disease Models, Animal; D000077206:Gabapentin; D006930:Hyperalgesia / Q000188:drug therapy*; D008297:Male; D009043:Motor Activity / Q000187:drug effects; D009437:Neuralgia / Q000188:drug therapy*; D010147:Pain Measurement; D017288:Pain Threshold / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D020426:Sciatic Neuropathy / Q000188:drug therapy*; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin