A recent retrospecitve study of over 830 patients with suspected or confirmed benzodiazepine overdose from the Florida State Poison Center Database showed that only 0.7% experienced subsequent seizure or seizure-like acitivity (i.e. dystonia, muscle rigidity) after flumazenil administration.
This study was conducted by emergency physicians from the University of Florida at Jacksonville where flumazenil is apparently often used as an antidote for benzodiazepine overdoses.
