xRead - Episodic Vertigo (January 2026)

10976817, 2020, S2, Downloaded from https://aao-hnsfjournals.onlinelibrary.wiley.com/doi/10.1177/0194599820909438 by Mayo Clinic Libraries, Wiley Online Library on [19/09/2025]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

Basura et al

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Benefits: Improved vertigo control, improved QOL Risk, harm, cost: Cost of therapy, side effects of medications, promotion of ineffective therapy Benefit-harm assessment: Balance of benefits and harm Value judgments: There are different practice pat terns among treating physicians on the panel. There is no specific preference for one agent over another, and that is why they were grouped for this statement. Intentional vagueness: None Role of patient preferences: Large Exclusions: Patients with comorbid conditions making these medications contraindicated (ie, renal or cardiac disease, asthma). Allergies or sensitivities to these medications Policy level: Option Differences of opinion: None Supporting Text The purpose of this statement is to inform clinicians about the role of oral medications as maintenance therapy in patients with chronic MD—recognizing that patients may vary in their response to these medications. It is important to note that these potential maintenance medications are intended for patients with active MD symptoms, not as abortive treatments for acute MD attacks. The underlying pathophysiology of MD is unclear; however, ELH has his torically been regarded as the histopathologic corre late. 228,229 Multiple etiologies have been proposed to explain the presence of ELH in MD patients. These etiolo gies include viral infection, 230-232 ionic imbalance, 233,234 genetic predisposition, 235-237 dietary factors, 238,239 autoim mune abnormalities, 240-243 vascular abnormalities, 244 and allergic responses. 245,246 Diuretics and betahistine have been used to reduce the frequency of MD attacks by targeting some of these mechanisms. 247 Diuretics are believed to alter the electrolyte balance in endolymph, subsequently reducing endolymph volume. 22 They are categorized by their mechanism of action and include thiazides (which inhibit sodium and chloride reab sorption from the distal convoluted tubules of the kidney), potassium sparing (which inhibits the sodium-potassium exchange within the collecting ducts), loop (which inhibits sodium reabsorption), and carbonic anhydrase inhibitors (which increase excretion of sodium, potassium, bicarbo nate, and water). 22,248 A Cochrane SR originally published in 2006 and updated in 2010 was conducted to assess the effect of diuretics on the frequency and severity of attacks (tinnitus, imbalance, hearing loss, and progression of symp toms) in patients with MD. 22 The authors identified 10 stud ies; however, none met the inclusion criteria due to problems with allocation (not randomized, n = 4; unclear allocation, n = 2; or not placebo controlled, n = 7) or prob lems with extracting data from placebo-controlled trials (n = 2). The 2 placebo-controlled RCTs that were excluded in

the Cochrane SR were the Klockhoff 1967 trial and the van Deelen 1986 trial. Those studies were both crossover trials that involved comparing either hydrochlorothiazide with placebo 249 or triamterene/hydrochlorothiazide with pla cebo, 250 but both were limited by not publishing data on the period of time before the crossover, thus being susceptible to the carryover phenomenon. While the effects of diuretics on MD could not be rigorously evaluated due to a lack of high-quality studies, some studies in the Cochrane SR did report improvement in patients’ vertigo with the use of diuretics. 20 The most commonly prescribed diuretics are thiazides with or without potassium-sparing diuretics such as hydro chlorothiazide/triamterene or spironolactone 251 as well as the carbonic anhydrase inhibitor acetazolamide (Diamox) as a second-line therapy. 20 Thiazides are contraindicated in patients with gout, and potassium-sparing diuretics are con traindicated in patients with acute or severe renal failure. 248 Since the prolonged use of thiazides can precipitate gout, other diuretic options should be considered. Clinicians should monitor electrolytes and blood pressure in patients who are prescribed diuretics. Betahistine dihydrochloride is an oral compounded medi cation that has been used worldwide for the treatment of peripheral vertigo. It is a histamine analog that strongly antagonizes histamine H3 receptors and acts as a weak ago nist on histamine H1 receptors. 252,253 While its mechanism of action remains unclear, it is not Food and Drug Admini stration approved for use in MD; therefore, conflicting evidence exists regarding whether it is beneficial in control ling vertigo. A 2016 Cochrane SR performed a meta analysis evaluating the effect of betahistine as compared with placebo in reduction of vertigo symptoms in patients with underlying vertigo (patient population included patients with MD, benign paroxysmal vertigo, and other vertigo). 254 The authors found that patients taking betahistine had a 30% greater rate of reduction in vertigo symptoms as com pared with those taking placebo (pooled risk ratio, 1.30; 95% CI, 1.05-1.60). 254 In other words, the number needed to treat would be 5 patients, meaning that a clinician would have to treat 5 patients with betahistine to have 1 patient report reduction in vertigo symptoms. For patients with MD (n = 139), the effect of betahistine was stronger than placebo, with MD patients reporting a 56% reduction in vertigo when taking betahistine as com pared with placebo (risk ratio, 1.56; 95% CI, 0.92-2.65). 254 These results, however, must be interpreted with caution. The quality of evidence for the primary outcome is low— the majority of the studies did not report clear randomiza tion strategies or implementation of blinding, both of which are critical in assessing a subjective outcome such vertigo. 254 Additionally, there was a large amount of statis tical and clinical heterogeneity in how the studies evalu ated vertigo, with few using validated tools. Therefore, the authors noted that better quality evidence is needed to evaluate the effectiveness of betahistine as compared with placebo. 254