A Cochrane review included 2 RCTs with a total of 50 participants. Both of these trials found a significant reduction in vertigo complaints in the gentamicin group when compared to the placebo group. Due to clinical heterogeneity a meta-analysis could not be performed. One study described an increase in hearing loss in 4 patients (25%) treated with gentamicin while the other described no increase in hearing loss. No other adverse effects were noted by either study.
Comment: The quality of evidence is downgraded by imprecise results (few studies and few patients).