Swystun 1998.

Methods	Setting: Canada, hospital outpatient clinic Length of intervention period: 7 days Randomisation: yes, computer‐generated randomisation sequence Allocation concealment: yes Design: 4 way crossover with 6 day washout periods Masking: double blind Excluded: not stated Withdrawals: stated Baseline characteristics: comparable Jadad score=4
Participants	12 adults: 5M 7F Age range: 20‐48 years Inclusion criteria: Adults with mild to moderate atopic asthma Documented response to a specific allergen in skin prick testing or inhalation challenge FEV1 (% predicted FEV1) > 70 Methacholine BHR (PC20 FEV1) 8 mg/ml or less Exclusion criteria: Requirement for any asthma medication in last 4 weeks Respiratory tract infection within last 4 weeks
Interventions	BUD: 1. 100 mcg 1 actuation 2xdaily (200 mcg/d) 2. 200 mcg 1 actuation 2xdaily (400 mcg/d) 3. 400 mcg 1 actuation 2xdaily (800 mcg/d) Placebo: 1 actuation 2xdaily Delivery device: Turbuhaler DPI
Outcomes	Allergen BHR (PC15 FEV1) Methacholine BHR (PC15 FEV1) FEV1
Notes	Reply from author to clarifying method of random order generation and that allocation concealment was employed.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Low risk	A ‐ Adequate