Comparison of the therapeutic efficacy of intravenous dimenhydrinate and intravenous piracetam in patients with vertigo: a randomised clinical trial Comparison of the therapeutic efficacy of intravenous dimenhydrinate and intravenous piracetam in patients with vertigo: a randomised clinical trial Emerg Med J 2015;32:520-524 doi:10.1136/emermed-2014-204006 Original article