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Source: Marill KA, et al. Ann Emerg Med. 2000;36:310-319.
Vertigo is one of the most commonly encountered and difficult to treat complaints in neurologic as well as general practice. A multitude of treatment options may be used, but none are clearly preferred as the agent with an ideal ratio of benefits to side effects. Anticholinergics, benzodiazepines, antihistamines, neuroleptics, and other agents have been used with variable success.
Marill and associates performed a study of 74 patients presenting to the emergency room (ER) with acute vertigo. Patients were prospectively randomized in a double-blind fashion to either intravenous lorazepam (2 mg) or dimenhydrinate (50 mg). The latter agent is available in oral form under the brand name Dramamine. It is a salt of the antihistamine diphenhydramine and 8-chlorotheophylline.
Vertigo was assessed by a 10-point patient rating scale. In a pilot study, vertigo during ambulation was found to be more sensitive than vertigo while lying in bed, sitting, or with head turn. This was, therefore, the primary outcome variable. The severity of vertigo during ambulation was also of practical significance as patients must be able to walk to be discharged from the ER. Secondary end points included symptoms such as nausea, treatment-related sedation, and overall "readiness to go home."
The mean magnitude of vertigo decreased from 6.4 to 2.6 (decrease = 3.8) in the dimenhydrinate group compared with 7.4 to 4.8 (decrease = 2.6) in the lorazepam group—a statistically significant difference. As Marill et al note, patients in the lorazepam group had higher pretreatment vertigo severity. In the overall cohort, however, patients with more severe vertigo benefited more from treatment. This would have biased in favor of lorazepam rather than against it.
Patients treated with lorazepam experienced significantly more sedation. Nausea decreased similarly in both treatment groups. Overall, 32 (86%) patients in the dimenhydrinate groups were "ready to go home" two hours after treatment compared with 25 (69%) in the lorazepam group. This assessment was made variably by the treating physician or the patients, with comparable results by either method.
As assessed by ER physicians, the discharge diagnosis assigned to the majority of patients was "acute vertigo," presumably of peripheral origin, rather than a more specific neurological disorder. It is not completely clear how many of the patients had true vertigo as opposed to more nonspecific dizziness. Patients were evaluated for nystagmus (present in > 60%) but not for other neurological signs. As Marill et al acknowledge, central vertigo (e.g., related to brainstem or cerebellar ischemia) probably comprised a negligible fraction of this population of patients (mean age = 45). Indeed, among the minority of patients in whom neuro-imaging was performed (n = 12, primarily CT), only one was positive (a cerebellar infarct). It is possible that patients with central-type vertigo were considered "too sick" for study enrollment or were considered ineligible due to concerns of stroke or TIA. Marill et al do not have specific data regarding these possible exclusions.
Despite these diagnostic considerations and the lack of any placebo-control group (considered unethical by Marill et al), this study is useful and important. An informal poll of neurologists in Marill et al’s practice showed that most did not consider Dramamine to be efficacious in their patients with vertigo. Rather, they commonly prescribe benzodiazepines for this purpose. The data from Marill et al suggest that Dramamine, an easily obtained over-the-counter preparation, may be equally or more effective than lorazepam, a schedule II drug that is restricted and has significant abuse potential.
Dr. Segal is Assistant Professor, Department of Neurology, Weill-Cornell Medical College, Attending Neurologist, New York Presbyterian Hospital, New York, NY.