title: Gabapentin Superadded to a Pre-Existent Regime Containing Amytriptyline for Chronic Sciatica.
abstract: There is currently a gross lack of evidence base guiding the medical management of chronic sciatica (CS). Only scant previous studies have assessed gabapentin (GBP) in CS. Extrapolating NICE-UK guidelines, prescribing authorities often insist on trialling anti-depressants (e.g., amytriptyline, AMP) as a first line for neuropathic pain states such as CS. When super-adding second-line agents, such as GBP, NICE-UK encourages overlap with first-line agents to avoid decreased pain-control. No study has reflected this practice.
  
  
  
  Evaluate efficacy and side effects (SE) of GBP superadded to a pre-existent regime containing AMP for CS.
  
  
  
  Prospective cohort of patients with unilateral CS attending a specialist spine clinic. Eligible patients had experienced partial benefit to a pre-existent regime containing AMP: none had significant SE. No drugs other than GBP were added or discontinued (the latter was considered inequitable) for 3 months. Visual analog pain score (VAS), Oswestry disability index (ODI), and SE were recorded.
  
  
  
  Efficacy: in 56% (43/77) there were reductions in VAS (5.3 ± 3.6→2.8 ± 2.7, P < 0.0001) and ODI (42.8 ± 31.1→30.7 ± 25.2, P = 0.008). SE: Eighty-two SE (23 types) were reported in 53% (41/77). Efficacy was less in those with SE: a trend existed for a lesser reduction in VAS (2.0 ± 2.4 v 3.0 ± 2.7, P = 0.08), which proved significant for ODI (8.1 ± 11.4 v 16.7 ± 18.2, P = 0.01). Thirty-four percent (26/77) discontinued GBP all within 1 week (i.e., during titration).
  
  
  
  This is the first prospective cohort study of GBP super-added to a pre-existent regime containing AMP for CS, as per routine clinical practice and NICE-UK principles. Super-added GBP demonstrated further efficacy over the previous regime in 56%; however, SE were frequent (53%) and diverse (23 types), and 34% abruptly discarded GBP. Although SE were associated with decreased efficacy, 37% nevertheless tolerated GBP despite SE.
authors.affiliation: *Department of Pharmacy, Medical Services Group, The Townsville Hospital, Townsville, Douglas, Queensland kelvin.robertson@health.qld.gov.au.|School of Medicine and Dentistry, James Cook University, Townsville, Douglas, Queensland.
authors.forename: Kelvin L
authors.initials: KL
authors.lastname: Robertson
authors.affiliation: School of Medicine and Dentistry, James Cook University, Townsville, Douglas, Queensland.|Department of Neurosurgery, Institute of Surgery, The Townsville Hospital, Townsville, Douglas, Queensland, Australia.
authors.forename: Laurence A G
authors.initials: LA
authors.lastname: Marshman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000588:Amines / Q000008:administration & dosage*; D000639:Amitriptyline / Q000008:administration & dosage*; D000700:Analgesics / Q000008:administration & dosage*; D002908:Chronic Disease; D015331:Cohort Studies; D003509:Cyclohexanecarboxylic Acids / Q000008:administration & dosage*; D004359:Drug Therapy, Combination; D005260:Female; D000077206:Gabapentin; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000187:drug effects* / Q000379:methods; D011446:Prospective Studies; D012585:Sciatica / Q000175:diagnosis* / Q000188:drug therapy*; D055815:Young Adult; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage*
chemical_list: D000588:Amines; D000700:Analgesics; D003509:Cyclohexanecarboxylic Acids; D000639:Amitriptyline; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin
keywords: Amitriptyline; Gabapentin; Neuropathic; Pain; Sciatica; Side-Effects