Brostoff 1996.

Methods	Design: randomised double‐blind multi‐centre 2‐arm trial of mizolastine vs placebo Duration: 28 days
Participants	Number of participants randomly assigned: 56; 28 in each group Sex: 55% male, 45% female Age of participants, years: 18; mean 38 ± 15 Unit of allocation: participant Country and setting: UK; setting research clinics Inclusion criteria of the trial Urticaria of at least 6 weeks' duration with at least 2 episodes per week Exclusion criteria of the trial Pregnant, women not using contraception, driving, dangerous machinery, inability to comply, concomitant disease or abnormal laboratory value Previous unresponsiveness to antihistamine: not stated
Interventions	Interventions, dose, duration After single‐blind placebo run‐in period of 4 to 10 days: Mizolastine 10 mg a day Placebo once daily for 28 days Duration of intervention: intermediate‐term (28 days)
Outcomes	Timing of outcome assessment: days 7 and 28 Primary outcomes of the trial Symptoms, including itch, sleep, daily activities, weals, erythema and discomfort rated on a 4‐point visual analogue scale Percentage of "responders" at 28 weeks Quality of life measures: none Secondary outcomes of the trial Dropouts due to inefficacy Adverse events and dropouts reported Clinician or participant report: clinician and participant
Notes	Study authors concluded that mizolastine controlled symptoms of urticaria
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote (page 321): ''a two‐centre, double‐blind randomised, placebo‐controlled parallel group study... allocated according to the randomisation"
Allocation concealment (selection bias)	Unclear risk	No details given about allocation concealment
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Quote (page 321): "Patients received single blind placebo medication for a variable period of 4‐10 days (initially, then were allocated to one of two treatment groups)" Quote (page 321): "All tablets were identical in appearance, ensuring double blind nature of trial." Unclear how investigators were blinded to treatment
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear how investigators were blinded to treatment Comment: participants probably blind, as all tablets were identical
Incomplete outcome data (attrition bias) All outcomes	High risk	29/56, 51% losses to follow‐up (29/56 with 10/28 in mizolastine arm and 19/28 in placebo arm). A large proportion of participants dropped out; this is unbalanced across trial arms 1 participant in mizolastine group did not take treatment Lack of efficacy in 5 in mizolastine group and in 17 in placebo group Drowsiness in 1 in mizolastine group Loss to follow‐up at day 7 in 2 mizolastine group 1 participant in each group "unco‐operative" 1 in each group discontinued for reasons unrelated to study Analysis in the paper is presented as ITT
Selective reporting (reporting bias)	Low risk	All prespecified outcomes were reported
Other bias	Unclear risk	Funder: Synthelabo Key outcome based on physician VAS estimate of urticaria severity (i.e. totally subjective); no indication of how many participants were cleared on treatment