Cannon 1994.

Study characteristics
Methods	Design: parallel Duration: 3 weeks Assessment: baseline and post‐intervention Country: USA
Participants	Pain condition: non‐cardiac chest pain Population: adults with non‐cardiac chest pain Minimum pain intensity: NR Inclusion criteria People with chest pain and normal coronary angiograms Psychiatric conditions included Exclusion criteria NR Total participants randomised: 60 Age in years (mean, range): 50 (29‐72) Gender: 40/60 were female Pain duration in months (mean, range): 53 (3‐175)
Interventions	Placebo n = 20 Inert Matched dosing schedule and identical capsules Clonidine 0.2 mg n = 20 Anti‐hypertensive Fixed dose of 0.2 mg/day Forced titration over 1 week Imipramine 50 mg n = 20 TCA Fixed dose of 50 mg/day Forced titration over 1 week
Outcomes	AEs
Missing data methods	NR
Funding source	Funding: NR
Conflicts of interest	NR
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomisation procedure 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, matched dosing schedules and identical appearance
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Self‐reported outcomes from blinded participants
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information given regarding dropout or missing data analyses ‐ could be that everyone completed the trial but NR Attrition NR
Selective reporting (reporting bias)	Unclear risk	No protocol or trial registration found
Other bias	Low risk	No other sources of bias were identified.