Efficacy of Benzodiazepines or Antihistamines for Patients With Acute Vertigo: A Systematic Review and Meta-analysis

Acute vertigo can be disabling. Antihistamines and benzodiazepines are frequently prescribed as "vestibular suppressants," but their efficacy is unclear.

To assess the efficacy of antihistamines and benzodiazepines in the treatment of acute vertigo from any underlying cause.

We searched the PubMed, CENTRAL, EMBASE, CINAHL, Scopus, and ClinicalTrials.gov databases from inception to January 14, 2019, without language restrictions. Bibliographies of the included studies and relevant reviews were also screened.

We included randomized clinical trials (RCTs) comparing antihistamine or benzodiazepine use with another comparator, placebo, or no intervention for patients with a duration of acute vertigo for 2 weeks or less. Studies of healthy volunteers, prophylactic treatment, or induced vertigo were excluded, as were studies that compared 2 medications from the same class.

Following Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, data were extracted and risk of bias was assessed by 2 authors independently for each study. Data were pooled using a random-effects model.

The predefined primary outcome was change in 10- or 100-point vertigo or dizziness visual analog scale (VAS) scores at 2 hours after treatment. Secondary outcomes included change in nausea VAS scores at 2 hours, use of rescue medication at 2 hours, and improvement or resolution of vertigo at 1 week or 1 month.

Of the 27 trials identified in the systematic review, 17 contributed to the quantitative meta-analysis and involved a total of 1586 participants. Seven trials with a total of 802 participants evaluated the primary outcome of interest: single-dose antihistamines resulted in significantly more improvement on 100-point VAS scores compared with benzodiazepines (difference, 16.1 [95% CI, 7.2 to 25.0]) but not compared with other active comparators (difference, 2.7 [95% CI, -6.1 to 11.5]). At 1 week and 1 month, neither daily benzodiazepines nor antihistamines were reported to be superior to placebo. RCTs comparing the immediate effects of medications (at 2 hours) after a single dose generally had a low risk of bias, but those evaluating 1-week and 1-month outcomes had a high risk of bias.

Moderately strong evidence suggests that single-dose antihistamines provide greater vertigo relief at 2 hours than single-dose benzodiazepines. Furthermore, the available evidence did not support an association of benzodiazepine use with improvement in any outcomes for acute vertigo. Other evidence suggested that daily antihistamine use may not benefit patients with acute vertigo. Larger randomized trials comparing both antihistamines and benzodiazepines with placebo could better clarify the relative efficacy of these medications.