['Diazepam and midazolam are commonly used by paramedics to treat seizures. A period of drug scarcity was used as an opportunity to compare their effectiveness in treating prehospital seizures.', 'A retrospective chart review of a single, large, commercial agency during a 29-month period was performed. The period included alternating shortages of both medications. Ambulances were stocked with either diazepam or midazolam based on availability of the drugs. Adult patients who received at least 1 parenteral dose of diazepam or midazolam for treatment of seizures were included. The regional prehospital protocol recommended 5\xa0mg intravenous (IV) diazepam, 5\xa0mg intramuscular (IM) diazepam, 5\xa0mg IM midazolam, or 2.5\xa0mg IV midazolam. Medication effectiveness was compared with respect to the primary end point: cessation of seizure without repeat seizure during the prehospital encounter.', 'A total of 440 study subjects received 577 administrations of diazepam or midazolam and met the study criteria. The subjects were 52% male, with a mean age of 48 (range 18-94) years. A total of 237 subjects received 329 doses of diazepam, 64 (27%) were treated with first-dose IM. A total of 203 subjects received 248 doses of midazolam; 71 (35%) were treated with first-dose IM. Seizure stopped and did not recur in 49% of subjects after parenteral diazepam and 65% of subjects after parenteral midazolam (p = 0.002). Diazepam and midazolam exhibited similar first dose success for IV administration (58\xa0vs. 62%; p = 0.294). Age, gender, seizure history, hypoglycemia, the presence of trauma, time to first administration, prehospital contact time, and frequency of IM administration were similar between groups.'] Is parenteral midazolam superior to diazepam for treatment of prehospital seizures?