Methods	Multicentre, randomised, double-blind, placebo-controlled, parallel-group, partial enrichment, LOCF, extended release formulation Gradual titration to 1800 mg over 2 weeks, then stable for 2 weeks (4 weeks in total)
Participants	Postherpetic neuralgia. N = 158, mean age 70 years, 53% women. Pain > 3 months after healing of skin rash, PI at randomisation ≥ 4/10, initial average daily pain score 6.5/10
Interventions	Gabapentin ER 1800 mg daily, n = 55 Gabapentin ER 1800 mg daily in split doses, n = 52 Placebo, n = 51 Rescue with paracetamol up to 4000 mg daily, or paracetamol plus hydrocodone 500 mg/5 mg up to 8 tablets daily
Outcomes	≥ 50% reduction in pain score ≥ 30% reduction in pain score PGIC much or very much improved Adverse events Withdrawals
Notes	Oxford Quality Score: R = 2, DB = 2, W = 1, Total = 5 Sponsored by Depomed
Risk of bias
Item	Authors’ judgement	Description
Allocation concealment?	Unclear	Not described
Blinding? All outcomes	Yes	Double-dummy method
Incomplete outcome data addressed? Efficacy	Unclear	LOCF
Size Efficacy	Unclear	158 randomised
Study duration Efficacy	Unclear	4 weeks
Outcomes reported	Yes	At least 50% reduction in pain