Prehospital IM midazolam for seizures

Intramuscular midazolam is at least as safe and effective as intravenous lorazepam for the prehospital management of status epilepticus. In his blog EM Literature of Note, Dr Ryan Radecki looks forward to a similar trial comparing nasal midazolam, which would reduce the risk from injections. Read his full critique here. Buccal midazolam 0.5 mg/kg is of course also an option, as described in the Advanced Paediatric Life Support manual:

If using the buccal route, draw up the higher dose (0.5mg) of the IV preparation using a needle (to avoid any fragments of glass from the ampoule) and after removing the needle, inject the drug into the buccal area between the lower bottom lip and the gum margin at the side of the mouth. Buccal midazolam is twice as effective as rectal diazepam, but both drugs produce the same level and degree of respiratory depression.

BACKGROUND: Early termination of prolonged seizures with intravenous administration of benzodiazepines improves outcomes. For faster and more reliable administration, paramedics increasingly use an intramuscular route.

METHODS: This double-blind, randomized, noninferiority trial compared the efficacy of intramuscular midazolam with that of intravenous lorazepam for children and adults in status epilepticus treated by paramedics. Subjects whose convulsions had persisted for more than 5 minutes and who were still convulsing after paramedics arrived were given the study medication by either intramuscular autoinjector or intravenous infusion. The primary outcome was absence of seizures at the time of arrival in the emergency department without the need for rescue therapy. Secondary outcomes included endotracheal intubation, recurrent seizures, and timing of treatment relative to the cessation of convulsive seizures. This trial tested the hypothesis that intramuscular midazolam was noninferior to intravenous lorazepam by a margin of 10 percentage points.

RESULTS: At the time of arrival in the emergency department, seizures were absent without rescue therapy in 329 of 448 subjects (73.4%) in the intramuscular-midazolam group and in 282 of 445 (63.4%) in the intravenous-lorazepam group (absolute difference, 10 percentage points; 95% confidence interval, 4.0 to 16.1; P<0.001 for both noninferiority and superiority). The two treatment groups were similar with respect to need for endotracheal intubation (14.1% of subjects with intramuscular midazolam and 14.4% with intravenous lorazepam) and recurrence of seizures (11.4% and 10.6%, respectively). Among subjects whose seizures ceased before arrival in the emergency department, the median times to active treatment were 1.2 minutes in the intramuscular-midazolam group and 4.8 minutes in the intravenous-lorazepam group, with corresponding median times from active treatment to cessation of convulsions of 3.3 minutes and 1.6 minutes. Adverse-event rates were similar in the two groups.

CONCLUSIONS: For subjects in status epilepticus, intramuscular midazolam is at least as safe and effective as intravenous lorazepam for prehospital seizure cessation. (Funded by the National Institute of Neurological Disorders and Stroke and others; number, NCT00809146.).

Intramuscular versus Intravenous Therapy for Prehospital Status Epilepticus
N Engl J Med. 2012 Feb 16;366(7):591-600