Intravenous lorazepam versus dimenhydrinate for treatment of vertigo in the emergency department: A randomized clinical trial

Study objective: To determine whether lorazepam is more effective than dime nhydrinate in relieving the symptom of vertigo in the emergency department setting. Methods: A prospective, randomized, double-blind trial of intravenous loraz epam versus dimenhydrinate therapy was conducted in the ED of a county-owne d, university-affiliated hospital. All adult patients who presented between January 24, 1998, and May 23, 1999, with the symptom of vertigo were eligi ble for inclusion. The intervention was varying the intravenous treatment b etween lorazepam, 2 mg, and dimenhydrinate, 50 mg. All patients received in travenous infusion of Ringer's lactate solution at a rate of 100 mL/h. Adeq uacy of randomization to the 2 treatment groups was assessed by comparing t he patients' relevant baseline history, physical examination, and symptoms. The predetermined primary outcome measurement was the patient's sensation of "vertigo with ambulation" 1 and 2 hours after treatment. Secondary outco me measurements included vertigo while lying, sitting, and turning the head , ability to ambulate as judged by the enrolling physician, and sensation o f nausea and drowsiness 1 and 2 hours after treatment, and whether the pati ent was "ready to go home" per patient report or physician assessment 2 hou rs after treatment. All patient symptoms were reported on 10-point scales. Outcome measurements were compared between the 2 treatment groups with a 2- way repeated-measures analysis of variance, Student's t test, Mann-Whitney U, and chi(2) test as appropriate. Results: Ten patients refused entry into the study, 16 were excluded, and 7 4 were enrolled, treated, and included in the analysis. One enrolled patien t had evidence of vertigo of central origin. The pretreatment values of ver tigo with ambulation were strongly correlated with the patient's ability to ambulate (P<.001), suggesting good internal validity. The patients randoml y assigned to the lorazepam group were sicker based on their pretreatment s ymptoms and ability to ambulate, and this may have biased the study results . The patients' symptom of "vertigo with ambulation" decreased 1.5 units mo re (95% confidence interval [CI] 0 to 3.0) on average on a 10-point scale 2 hours after treatment in the dimenhydrinate group. All other measures of v ertigo also decreased more in the dimenhydrinate group, although the differ ences were not statistically significant. At 2 hours after treatment, the p atients' ability to ambulate was better in the dimenhydrinate group (P<.001 ), and 17% (95% CI -2 to 36) more patients in this group were "ready to go home." Patients in the lorazepam group experienced a 1.8-unit (95% CI 0.2 t o 3.4) greater increase in drowsiness 2 hours after treatment. Conclusion: Our results suggest that dimenhydrinate was more effective in r elieving vertigo and less sedating than lorazepam at the intravenous doses administered in this study. Dimenhydrinate appears to be the preferred medi cine for patients who present to the ED with vertigo likely to be of periph eral origin.