Johansson 1979.

Study characteristics
Methods	Design: parallel Duration: 4 weeks Assessment: baseline and post‐intervention Country: Sweden
Participants	Pain condition: chronic pain conditions Population: people hospitalised at the Department of Neurology, University of Umeå with chronic pain syndromes Minimum pain intensity: no Inclusion criteria Pain syndromes of at least 6 months with a stable course All possibilities of active treatment tried Exclusion criteria: NR Total participants randomised: 40 Age in years (range): 25‐65 Gender: 23/40 were female Pain duration in years (mean, SD): NR
Interventions	Placebo n = 20 Inert Matched dosing schedule Zimelidine 200 mg n = 20 SSRI Fixed dose with forced titration
Outcomes	Pain intensity Withdrawal
Missing data methods	Completer analysis
Funding source	NR
Conflicts of interest	NR
Notes	Zimelidine has been banned worldwide due to serious, sometimes fatal, cases of central and/or peripheral neuropathy known as Guillain‐Barré syndrome and due to a peculiar hypersensitivity reaction involving many organs including skin exanthema, flu‐like symptoms, arthralgias, and sometimes eosinophilia. Additionally, zimelidine was found to cause an increase in suicidal ideation and/or attempts among depressive patients.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Patients were then according to a randomisation list given tablets of identical form, color and taste, containing either Zimelidine 25 mg or a placebo according to a fixed dose regimen"
Allocation concealment (selection bias)	Unclear risk	Allocation procedures not specified
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double‐blind, matched dosing and appearance of study drugs
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	HIgh attrition in Zimeldine arm. Reported compeleter analysis only, with no missing data methods Attrition Total: 8/20 (40.0%) Placebo: 3/11 (27.3%) Zimeldine 200 mg: 5/9 (55.6%)
Selective reporting (reporting bias)	Unclear risk	No protocol found
Other bias	Low risk	No other sources of bias were identified.