Petersen 1997.

Methods	Design: randomised, placebo‐controlled, parallel‐group trial
Participants	Number assigned: 212 adults (macrolide n = 93, placebo n = 93, excluded n = 26) Age in years (median): macrolide: 25, placebo: 26 Setting: primary care
Interventions	Indication: pharyngitis not caused by group A Streptococcus Type of macrolide: erythromycin base Route: per oral Dose per day: 999 mg Duration of treatment: 10 days Total treatment dose: 9990 mg
Outcomes	Adverse events stated as an outcome in trial registration/protocol/paper: unclear Adverse events ascertainment: participant diary used Adverse events: data reported on day 1, 3, and 6 Antimicrobial resistance: not reported Death: not reported
Funding sources	Supported by Henry J Kaiser Foundation and The Upjohn Company
Notes	Concomitant medication: yes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Sequence generation not described.
Allocation concealment (selection bias)	Unclear risk	Allocation not described.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Identical‐appearing placebo
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Participants and clinicians blinded.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Low dropout, similar between groups
Selective reporting (reporting bias)	Low risk	Adverse events not clearly stated as an outcome. However, standardised ascertainment and adverse events reported. Reported on adverse events as %, not numbers, assume that this is out of the total analysed.
Other bias	Low risk	None were identified.