Methods	Randomised, double-blind, active placebo-controlled, cross-over. Analyses included all data available assuming that missing data were missing at random Titration over 1 week of gabapentin at pre-study dose (up to 4800 mg daily), tramadol 50 mg “q.i.d.” (probably once daily in USA - officially 4 times daily), or diphenhydramine 50 mg “qhs” (qh = every hour, but more likely 4 × daily) as active placebo, then stable dose for 1 week (2 weeks in total); 1-week washout, then cross-over to next treatment
Participants	Painful small fibre sensory neuropathy with gabapentin-sensitive pain that worsened with placebo, in a complete enrichment design. N = 18, mean age 59 years, 44% women. Pain at randomisation > 3, initial mean pain score 4.9/10
Interventions	Gabapentin 4800 mg daily (max) Tramadol 200 mg daily (max) Placebo Stable pain medication other than gabapentin was continued Paracetamol (325 mg tablets, dose not specified) allowed for rescue medication. If inadequate patient could take additional 400 mg gabapentin, up to 1200 mg daily
Outcomes	≥ 50 improvement in pain ≥ 30 improvement in pain PGIC very much better PGIC much or very much better Withdrawals
Notes	Oxford Quality Score: R = 2, DB = 2, W = 1, Total = 5
Risk of bias
Item	Authors’ judgement	Description
Allocation concealment?	Yes	Remote allocation
Blinding? All outcomes	Yes	“matching capsules”
Incomplete outcome data addressed? Efficacy	Unclear	Imputation not mentioned
Size Efficacy	No	54 randomised to 3 groups. Gabapentin comparison with placebo 36 patients maximum
Study duration Efficacy	No	2 weeks
Outcomes reported	Yes	At least 50% reduction in pain