Foster 2010b.

Study characteristics
Methods	Design: parallel Duration: 12 weeks Assessment: baseline and post‐intervention Country: USA and Canada
Participants	Pain condition: Interstitial Cystitis/Painful Bladder Syndrome Population: people with painful bladder pain with no prior treatment experience for IC/PBS. Minimum pain intensity: ≥ 3 on 0‐10 VAS Inclusion criteria ≥ 3 on 0‐10 pain intensity VAS ≥ 3 on 0‐10 symptom score of abnormal urinary frequency VAS No prior significant treatment for IC/PBS Exclusion criteria Physical and mental health comorbidities Total participants randomised: 271 Age in years (median): 38 Gender: 216/271 were female Pain duration in years (mean): 6.4
Interventions	Placebo n = 136 Inert Matched dosing schedule Amitriptyline 25‐75 mg n = 135 TCA Flexible dosing based on tolerability
Outcomes	Pain intensity AEs Withdrawal
Missing data methods	ITT but do not specify missing data methods
Funding source	Non‐pharmaceutical: National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), collaborator: University of Pennsylvania
Conflicts of interest	Dr Foster reports having no conflicts. Dr Hanno reports Astellas, Pfizer, and Trillium. Dr Nickel reports receiving consulting fees from Merck, Glaxo‐Smith‐Kline, Pfizer, Ortho Women's Health, Farr Labs, Watson, Medtronic, NeurAxon, Genyous Biomed and research support from Merck, Glaxo‐Smith Kline, Allergan, Watson, Pfizer and American Medical Systems. Dr C. Yang reports Medtronic. Dr Chai reports Pfizer and Allergan. Dr Kusek reports holding stock in deCode Genetics. No other potential COI relevant to this manuscript was reported.
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	States double‐blind but no information given regarding study drug appearance
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	Unclear risk	State ITT but no imputation methods specified Attrition Total: 40/271 (14.8%) Placebo: 17/136 (12.5%) Amitriptyline 25‐75 mg: 23/135 (17.0%)
Selective reporting (reporting bias)	High risk	Primary outcome reported according to protocol, not all secondary outcomes reported. Added new outcomes into the outcome measures under methods but never report the outcome for these.
Other bias	Low risk	No other sources of bias were identified.