Intravenous promethazine versus lorazepam for the treatment of peripheral vertigo in the emergency department: A double blind, randomized clinical trial of efficacy and safety.

Background: Vertigo imposes considerable health restrictions with significant impact on the patient's quality of life. The most effective antivertigo agent is undetermined thus far.

Objective: This study was performed to assess whether promethazine has superior vertigo reduction compared with lorazepam in ED patients.

Methods: In this randomized, double-blind, parallel group trial 184 patients were assigned (1:1 ratio) to receive either promethazine, 25 mg intravenously, or lorazepam, 2 mg intravenously. Primary endpoint was mean change in vertigo intensity at 2 hours measured using visual analog scale (VAS). Secondary endpoints were mean change in nausea score, need for second dose of study medications, and adverse events (AEs).

Results: Promethazine was associated with significantly more reduction (46.5 mm) in vertigo than lorazepam (25.7 mm, p< 0.001). Mean change in nausea score 2 hours after drug injection on the VAS was 28.7 mm for promethazine and 22.8 for lorazepam (p=0.002). The most frequently reported AEs were lethargy (14.1% in lorazepam group, 4.3% in promethazine group, p=0.013) and drowsiness (10.8% for promethazine, 2.1% for lorazepam, p=0.017).

Conclusion: Our study demonstrated the evidence that promethazine is superior to lorazepam in management of peripheral vertigo and vertigo-related nausea in ED adults.