Background The present study aimed to compare the therapeutic efficacy of dimenhydrinate and piracetam in patients with vertigo.

Methods A blinded, parallel group, superiority, randomised clinical trial was carried out on patients who presented to the emergency department (ED) with vertigo. Healthy adult patients presenting to the ED with undifferentiated vertigo were included in the study. The efficacy of intravenous dimenhydrinate (100 mg) and intravenous piracetam (2000 mg) for reducing the intensity of vertigo was compared in two randomised treatment groups using a 10-point numeric rating scale (NRS). The determination of NRS scores was performed at presentation and at the 30th minute of presentation, after the study drug was implemented, both in immobile and ambulatory positions. The primary outcome variable was reduction in vertigo intensity documented on the NRS at the 30th minute after medication administration, analysed by intention to treat.

Results A total of 94 patients were included in the randomisation (n=47 in both groups). The baseline NRS scores were 7.55±2.00 in the dimenhydrinate group and 8.19±1.79 in the piracetam group. The changes from baseline for dimenhydrinate and piracetam were 2.92±3.11 and 3.75±3.40 (difference −0.83 (95% CI −2.23 to 0.57)) in the immobile position and were 2.04±3.07 and 2.72±2.91 (difference −0.68 (95% CI −2.03 to 0.67)) in the ambulatory position. Rescue medication need was similar in both treatment groups (p=0.330), and only one adverse reaction was reported.

Conclusions We found no evidence of a difference between dimenhydrinate and piracetam in relieving the symptoms of vertigo.

Trial registration number Clinical Trials Registration ID: NCT01890538