NCT00475904.

Methods	Randomised, double‐blind, double‐dummy, placebo‐controlled, parallel groups, 4 weeks, not enriched
Participants	PHN ≥ 3 months after healing of rash. Age ≥ 18 years N = 360 Mean age 53 years, 38% women
Interventions	Gabapentin 1800 mg daily, n = 144 Topical cream with amitriptyline and ketamine, n = 140 Placebo for oral and topical cream, n = 76
Outcomes	Mean reduction in PI from baseline
Notes	Oxford Quality Score: R = 1, DB = 2, W = 1, Total = 4
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐dummy method
Incomplete outcome data (attrition bias) Efficacy	Unclear risk	LOCF imputation
Size Efficacy	Unclear risk	50‐200 participants per treatment arm (76 to 144)