Chalmers 1985.

Methods	Randomised, double‐blind, placebo‐controlled cross‐over trial for 2 successive 6‐month periods.
Participants	17 people with CF (7 males, 10 females) age range 5 ‐ 19 years. Results reported from the 13 who gave adequate faecal samples.
Interventions	2 groups: 1. usual enzyme therapy plus cimetidine 25 mg/kg/day; 2. usual enzyme therapy plus placebo.
Outcomes	Faecal fat, weight, nitrogen, bile acids, anthropometric measurements, bone age, peak flow, Crispin Norman score, Shwachman score, haemoglobin, albumin, calcium, creatinine and plasma vitamin A levels.
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‐blind in text but no further details given.
Incomplete outcome data (attrition bias) All outcomes	Low risk	At 10 months 1 participant withdrew from group originally assigned to cimetidine (withdrew whilst taking placebo) due to deterioration in respiratory function. This left 8 participants in each group.