Ricci 1987.

Study characteristics
Methods	Allocation: "randomisation list" Design: parallel‐group
Participants	Number: 10 analysed Age: mean 36 Gender: 6 M, 4 F Setting: outpatients, Italy Eligibility criteria: Ménière's syndrome, investigator‐definedExclusion criteria: allergy to betahistine, ulcer, other medical conditions as defined Baseline characteristics: similar baseline characteristics
Interventions	Betahistine 8 mg 3 times a day versus placebo for variable duration (10 x mean duration of interval between attacks for each patient) Intervention group: n = 5 Comparator group: n = 5 Use of additional interventions: none
Outcomes	Primary outcome: narrative only (description of each patient's history)Secondary outcomes: none
Funding sources	Not stated
Declarations of interest	Not stated
Notes	Participants lost to follow‐up: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomisation list"
Allocation concealment (selection bias)	Unclear risk	Method not stated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Double‐blind, but no further information
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Double‐blind, but no further information
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information
Selective reporting (reporting bias)	High risk	Limited outcome data and no information on adverse events
Other bias	Unclear risk	—