Backonja 2011.

Methods	Randomised, double‐blind, placebo‐controlled, parallel groups, enriched for tolerance (but not response), LOCF Open‐label titration with gabapentin from 300 mg at night to maximum 600 mg 3 times daily (1800 mg/d) over 4 days, maintained on maximum tolerated dose for 7 days, then randomised to double blind treatment with 600 mg gabapentin encarbil twice daily or placebo for 2 weeks
Participants	PHN. Pain > 3 months after healing of skin rash. PI at randomisation ≥ 40/100 N = 102 in double‐blind phase, and 116 in open‐label phase Mean age 65 years, 51% women Initial average daily pain score 6.1/10, and 4.5 before randomisation
Interventions	Gabapentin encarbil 1200 mg daily, n = 47 (equivalent to 624 mg gabapentin, given as divided dose) Placebo, n = 54 Antiepileptic medication discontinued ≥ 7 days before open label phase. Antidepressant and narcotic analgesics continued if stable > 1 month
Outcomes	≥ 50% reduction in pain ≥ 30% reduction in pain PGIC much and very much improved Withdrawals Adverse events
Notes	Oxford Quality Score: R = 1, DB = 2, W = 1, Total = 4 XenoPort sponsored
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not described
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) All outcomes	Low risk	"matching placebo"
Incomplete outcome data (attrition bias) Efficacy	Unclear risk	LOCF imputation
Size Efficacy	High risk	< 50 participants per treatment arm