Schoni 1984.

Methods	Randomised, double‐blind placebo‐controlled trial over 4 months.
Participants	38 children with CF (22 males, 16 females) mean age 12 years and 13.5 years respectively. Participants grouped according to acetylation phenotype (slow or fast) and matched according to their age before the trial. No withdrawals mentioned.
Interventions	2 groups: 1. cimetidine 600 mg/m2 BSA; 2. placebo.
Outcomes	Clinical state, weight, height, skinfold thickness, lung function tests, PABA peptide test, plasma lipid and lipoprotein.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised, but no details of method given.
Allocation concealment (selection bias)	Unclear risk	Not discussed
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Described as double‐blinded in text but no further details given
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No withdrawals mentioned.