Maqbool 2010.

Methods	A 2‐armed, parallel‐group randomised controlled trial with 2 months duration of treatment and 2 months duration of follow‐up
Participants	Location: Rawalpindi, Pakistan Setting: single‐centre study, Department of Otorhinolaryngology, Combined Military Hospital Rawalpindi, from July 2006 to December 2006 Sample size: Number randomised: 35 in betahistine group and 35 in multivitamin group Number completed: not reported Participant baseline characteristics: Age (mean (SD) years): 48 (14) in betahistine group versus 49 (12) in multivitamin group Gender (male/female, n): 35/0 in betahistine group versus 35/0 in multivitamin group Tinnitus loudness (dB (SD)): 6 (2) in betahistine group versus 6 (2) in multivitamin group Inclusion criteria: patients aged over 18 years with tinnitus due to noise‐induced hearing loss with a confirmed history of exposure to noise and confirmed hearing loss at 3 or 4 kHz Exclusion criteria: Tinnitus due to other causes Diabetes Hypertension Peptic ulcer disease Alcoholics
Interventions	Intervention group: betahistine hydrochloride tablets, 48 mg daily (16 mg 3 times a day), 2 months Comparator group: multivitamin tablets, 3 tablets daily (1 tablet 3 times a day), 2 months Use of additional interventions: none reported
Outcomes	Tinnitus loudness measured using a visual analogue scale (range 0 to 10) at 1 month and 2 months
Funding sources	No information provided
Declarations of interest	No information provided
Notes	—
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Methods of randomisation not reported
Allocation concealment (selection bias)	Unclear risk	Methods of allocation concealment not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported whether participants and/or personnel were blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported whether outcome assessors were blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not reported whether participants dropped out or were lost to follow‐up. Not reported whether outcome data were missing.
Selective reporting (reporting bias)	Low risk	There is no protocol available. The outcomes listed in the patients and methods section of the article are all reported in the results section of the article.
Other bias	Unclear risk	Conflicts of interest and funding were not reported