Goldenberg 1986.

Study characteristics
Methods	Design: parallel Duration: 6 weeks Assessment: baseline and post‐intervention Country: USA
Participants	Pain condition: fibromyalgia Population: adults with fibromyalgia Minimum pain intensity: ≥ 4 on 0‐10 VAS Inclusion criteria Fibromyalgia matching criteria reported by Yunus 1983 At least 3 months' duration ≥ 4 on 0‐10 pain intensity VAS Exclusion criteria History of peptic ulcer disease or cardiac arrhythmias Total participants randomised: 62 Age in years (mean, range): 43.8 (21‐69) Gender: 59/62 were female Pain duration in years (mean, range): 3.5 (0.25‐20)
Interventions	Amitriptyline 50 mg + naproxen 1000 mg n = NR Combined intervention: TCA + NSAID Fixed doses Placebo + naproxen 1000 mg n = NR NSAID Fixed dose Double‐dummy design Amitriptyline 50 mg + placebo n = NR TCA Fixed dose Double‐dummy design Placebo + placebo n = NR Double dummy to match intervention arms
Outcomes	Withdrawal
Missing data methods	Completer analysis
Funding source	Partly pharmaceutical: supported by grants from the Arthritis Foundation, Multipurpose Arthritis Center grant no. AM‐20613, and a clinical investigator grant from Syntex Co.
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 procedures not specified
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Double‐dummy design, but no information on study drug appearance and dosing
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Self‐reported outcomes from participants, but unsure of blinding procedures
Incomplete outcome data (attrition bias) All outcomes	Low risk	Completer analysis but very low dropout Attrition Total: 4/62 (6.5%) Attrition per arm NR
Selective reporting (reporting bias)	High risk	Only present the data for the groups that had significant differences. No protocol or trial registration found
Other bias	Low risk	No other sources of bias were identified