Gilron 2009.

Study characteristics
Methods	Design: cross‐over Duration: 6 weeks Assessment: baseline and post‐intervention Country: Canada
Participants	Pain condition: neuropathic pain from diabetic peripheral neuropathy or post‐herpetic neuralgia Population: adults with diabetic polyneuropathy or post‐herpetic neuralgia Minimum pain intensity: ≥ 4 on 0‐10 VAS Inclusion criteria diagnoses of either diabetic peripheral neuropathy or post‐herpetic neuralgia ≥ 4 on 0‐10 pain intensity VAS Exclusion criteria Physical and mental health comorbidities Total participants randomised: 56 Age in years (median, range): diabetic peripheral: 61 (53‐69); post‐herpetic: 68 (65‐73) Gender: 21/56 were female Pain duration in years (median, range): diabetic peripheral: 5.2 (3.4); post‐herpetic: 2.8 (4.3)
Interventions	Gabapentin ≤ 3600 mg n = 51 Anticonvulsant Flexible dosing dependent on tolerability Double‐dummy design Nortriptyline ≤ 100 mg n = 51 TCA Flexible dosing dependent on tolerability Double‐dummy design Nortriptyline ≤ 100 mg and gabapentin ≤ 3600 mg n = 51 Combined intervention: TCA + anticonvulsant Flexible dosing dependent on tolerability Double‐dummy design
Outcomes	Pain intensity Sleep Mood Physical fucntion SAEs Withdrawal
Missing data methods	ITT but no method specified
Funding source	Non‐pharmaceutical: Canadian Institutes of Health Research (grant numbers MCT‐69422 and MSH‐55041)
Conflicts of interest	IG has received honoraria for consulting or being a member of an advisory board, or both for Pfizer. RLH has received research grant support from Pfizer. All other authors declare that they have no conflicts of interest.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants were randomised using computer randomisation of the 3 sequences in blocks of 3.
Allocation concealment (selection bias)	Low risk	A trial pharmacist prepared a concealed allocation schedule, and the pharmacist had no further involvement in the trial. Patients were assigned in turn to the next consecutive number, and the corresponding series of study drugs was dispensed.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind, double‐dummy design
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Self‐reported outcomes from blinded participants
Incomplete outcome data (attrition bias) All outcomes	High risk	ITT with LOCF, unequal dropout Attrition Total: 11/56 (19.6%) Gabapentin ≤ 3600 mg: 8/56 (14.3%) Nortriptyline ≤ 100 mg: 1/56 (1.8%) Gabapentin ≤ 3600 mg + nortriptyline ≤ 100 mg: 2/56 (3.6%)
Selective reporting (reporting bias)	Unclear risk	Can't find global pain relief reported in study (was stated in prospective ISRCTN registration). In the protocol, the Profile of Mood State questionnaire was listed as a secondary outcome but it is NR.
Other bias	Low risk	No other sources of bias identified