Morello 1999.

Study characteristics
Methods	Design: cross‐over Duration: cross‐over periods were 6 weeks Assessment: baseline and post‐intervention Country: USA
Participants	Pain condition: diabetic peripheral neuropathy Population: type 1 and 2 diabetic veterans with diabetic peripheral neuropathy pain Minimum pain intensity: no Inclusion criteria Chronic daily pain for > 3months, during which both the quality and location were consistent with diabetic peripheral neuropathy pain, as diagnosed by a neurologist Exclusion criteria Physical and mental health comorbidities Total participants randomised: 25 Age in years (mean, SD): 60.4 (10.8) Gender: 1/25 were female Pain duration in years (mean, SD): 5.7 (4.2)
Interventions	Gabapentin 900‐1800 mg Anticonvulsant Flexible dosing dependent upon tolerance Mean dose after titration: 1565 mg/day Amitriptyline 25‐75 mg TCA Flexible dosing dependent upon tolerance Mean dose after titration: 59 mg/day
Outcomes	Pain intensity AEs Withdrawal
Missing data methods	Completer analysis only
Funding source	NR
Conflicts of interest	NR
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation methods not specified
Allocation concealment (selection bias)	Unclear risk	Allocation procedure not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind medications, same dosing schedules and appearance
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Self‐reported outcomes by blinded participants
Incomplete outcome data (attrition bias) All outcomes	High risk	Completer‐only analysis Attrition Total: 4/25 (16.0%) Gabapentin 900‐1800 mg: 2/25 (8.0%) Amitriptyline 25‐75 mg: 2/25 (8.0%)
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration found
Other bias	High risk	Post hoc power analysis and report needing sample of 280 to detect effect, they have 25 participants randomised