There is insufficient evidence from randomized controlled trials (RCTs) to conclude whether betahistine prevents Meniere's disease symptoms. Some trials suggest that betahistine may help control vertigo, dizziness, or imbalance but the quality of the trials is limited. CKS was unable to find any systematic reviews or RCTs investigating the effects of betahistine for acute attacks of Meniere's disease.

• A Cochrane review (search date: December 1999) investigated the use of betahistine versus placebo in people with Meniere's disease [James and Burton, 2001].
• Six RCTs were found (n = 162), but study sizes were small and there was heterogeneity between studies in terms of:
• Diagnostic criteria.
• Outcome measures.
• The dose and duration of betahistine used.
• Most trials suggested a reduction of vertigo with betahistine and some suggested a reduction in tinnitus but all these effects may have been caused by bias in the methods.
• One trial (n = 35) with good methods showed no effect of betahistine on tinnitus compared with placebo.
• None of the trials showed any change in hearing as assessed by pure tone audiograms.
• Betahistine appeared to be well tolerated and no adverse effects were found with its use.
• A more recent double-blind multi-centre RCT (n = 81) compared the efficacy and safety of betahistine to that of a placebo in recurrent vertigo resulting from Meniere's disease [Mira et al, 2003].
• Betahistine 16 mg twice a day was found to significantly:
• Reduce the frequency of attacks of vertigo.
• Increase the proportion of people reporting a reduction in severity of vertigo over 3 months compared with placebo.
• However, the results should be interpreted with caution as confidence intervals were not reported, and data was not reported on the number of people with each outcome, severity of symptoms, or effects on hearing.