Antihistamines provided greater relief for patients with acute vertigo than benzodiazepines, however, other medications yielded similar results as antihistamines, according to a systematic review and meta-analysis published in JAMA Neurology.
For the study, researchers compared the efficacy of antihistamines and benzodiazepines in improving vertigo symptoms, reflected as a change in 10- or 100-point vertigo or dizziness visual analog scale (VAS) at 2 hours following treatment. In their systematic review, the researchers identified 17 randomized clinical trials (RCTs) that included 1586 participants, for their meta-analysis. Seven out of 17 RCTs, which included a total of 802 participants, were analyzed for the study’s primary outcome of change in VAS scores 2 hours after treatment.
Most enrolled participants had generalized or nonspecific peripheral vertigo. In these studies, participants received a range of “vestibular suppressants,” including antihistamines (betahistine, cinnarizine, dimenhydrinate, flunarizine, meclizine, and promethazine), benzodiazepines (lorazepam and diazepam), along with placebos and other nonbenzodiazepines (ondansetron, droperidol, metoclopramide, and piracetam).
Compared with single-dose benzodiazepines, single-dose antihistamines led to a 16.1-point (95% CI, 7.2-25.0) reduction in vertigo symptoms on the 100-point VAS 2 hours posttreatment. However, antihistamines had a similar effect as other active comparators, by a difference of 2.7 points (95% CI, -6.1 to 11.5). No significant data supported benzodiazepines improving or alleviating symptoms of vertigo 1 week or 1 month posttreatment. At week 1 or 1 month, neither daily benzodiazepines nor antihistamines were found to be superior to placebo, the researchers noted.
“Daily antihistamine use may not be superior to placebo or no treatment for improvement at 1 week or 1 month, but this is based on very weak evidence from heterogenous [sic] trials with a high [risk of bias],” the researchers stated.
Study limitations included lack of larger RCTs comparing antihistamines vs benzodiazepines in existing literature or lack of contact from other study authors conducting similar trials in decades past. The tendency “to favor interventions over controls,” resulting in high risk of bias in data collected 1 week to 1 month posttreatment was also noted. The researchers also recognized potential medicinal effectiveness at 1 hour posttreatment vs 2 hours.
Researchers wrote, “Treatment of acute vertigo is challenging. There is general consensus that repositioning maneuvers are the preferred first-line treatment for [benign positional paroxysmal vertigo]. However, these maneuvers are not always effective, and patients often require further intervention for vertigo symptoms.”
Larger randomized trials that compare both antihistamines and benzodiazepines with placebo are warranted to verify the efficacy of these medications for acute vertigo, the researchers concluded.
Hunter BR, Wang AZ, Bucca AW, et al. Efficacy of benzodiazepines or antihistamines for patients with acute vertigo: a systematic review and meta-analysis. JAMA Neurol. Published online July 18, 2022. doi:10.1001/jamaneurol.2022.1858