Comparative Efficacy of Prochlorperazine and Promethazine for Acute Vertigo in the Emergency Department: A Randomized Clinical Trial

Abstract

Background: Vertigo represents a subset of dizziness, and the mainstay of pharmacotherapy in the emergency department (ED) is the use of vestibular suppressants. Numerous studies have demonstrated that antihistamines are effective vestibular suppressants and provide substantial relief for acute vertigo patients. However, no studies have evaluated the use of prochlorperazine for acute vertigo despite its common prescription in EDs. This study aimed to compare the efficacy of intramuscular prochlorperazine versus intramuscular promethazine for treating acute vertigo in the ED.

Methods: A randomized, single-blinded study comparing 12.5 mg intramuscular prochlorperazine versus 25 mg intramuscular promethazine was conducted in adult patients who presented with acute vertigo. Patients were randomized using a random number of tables and a permutated block of four. Periodic assessment of the vertigo analogue score (VAS) was performed at 1- and 2-hour intervals. The primary outcome was the mean reduction in the VAS score. Side effects and drug evaluations were conducted within 2 hours of drug administration.

Results: There was no statistically significant difference in the reduction in the mean VAS score between patients in the prochlorperazine and promethazine groups. The mean VAS scores for patients treated with prochlorperazine were 8.43 at 0 minutes, 5.00 at 1 hour, and 3.13 at 2 hours. In contrast, the mean VAS scores for patients who received promethazine were 8.81 at 0 minutes, 6.63 at 1 hour, and 4.94 at 2 hours. Seventy-five percent of patients in the prochlorperazine group were ready for discharge, compared to only 44% in the promethazine group. However, patients in the prochlorperazine group were 1.80 times more likely to develop orthostatic hypotension (relative risk [RR] = 1.80; 95% confidence interval [CI] = 0.97, 3.35).

Conclusion: Intramuscular prochlorperazine demonstrated a nonsignificant trend toward superiority over intramuscular promethazine for acute vertigo management, providing better relief and increasing discharge readiness.