Additional Study Information: Meniere's Disease is an inner ear disorder that causes episodes of vertigo. The purpose of this study is to test the effectiveness and safety of OTO-104 compared to placebo in subjects with Menieres disease. OTO-104 contains an active ingredient, called dexamethasone, which is a commonly used corticosteroid that has been prescribed by doctors for several decades. Some doctors have injected dexamethasone into the ear to treat the symptoms of Menieres disease. They used versions of dexamethasone that do not form gels when injected into the ear and the dexamethasone drained out of the ear. In these instances, the dexamethasone may not have been in the ear long enough to reduce symptoms of Menieres disease. This study will investigate whether turning OTO-104 into a gel within the ear and holding the dexamethasone in place may improve Menieres disease symptoms. The substance that turns OTO-104 into a gel is called poloxamer 407.