• The binary outcome variable measuring whether or not there is termination of convulsive seizure activity prior to ED arrival after an initial dose of study medication without the need for a second rescue dose of benzodiazepine by EMS [ Time Frame: Duration of prehospital care, outcome is determined upon arrival at the ED on the day of enrollment. ] [ Designated as safety issue: No ]
  

• Times from EMS arrival to convulsive seizure termination & from treatment initiation to seizure termination, frequency of endotracheal intubation, frequency & duration of hospitalization & ICU admission, & frequency of acute seizure recurrence. [ Time Frame: All time interval outcomes are measured during prehospital care on the day of enrollment, other secondary outcomes are determined on the day of enrollment, at 24 hours, and at hospital discharge or on hospital day 90. ] [ Designated as safety issue: Yes ]
  

Seizures are a common medical problem. Although they can be frightening to watch, most seizures are brief and stop by themselves. Seizures that don't stop in seconds or minutes are a dangerous life-threatening medical emergency. Paramedics often have medications that can stop seizures, but the best way to give the medicines is not known. Paramedics often give medicine directly into a vein, which is called intravenous (IV) administration. This works well, but can be hard to do in a person who is seizing. It can also take some time and delay treatment. Another way to give the medicine is as a shot given into a muscle, which is called intramuscular (IM) administration. Giving the medicine this way is faster, but it may not stop the seizure as quickly.

This clinical trial is designed to figure out whether giving anti-seizure medicine works similarly well and more quickly when given through an IV or when given as a shot in the muscle. Two similar medicines will be used. Both are already used by paramedics in the field and by doctors in the hospital to stop seizures. One is commonly given by IV, and the other is commonly given as a shot in the muscle. In this study, the shot will be given using a device similar to an EpiPen—which is an autoinjector used by people with severe allergies.

Approximately 800 persons whose seizures are continuing after emergency medical service (EMS) arrival and who meet all eligibility criteria will be enrolled in the trial. Every participant will be treated with anti-seizure medicine by the paramedics. At random, half the participants will be in one group and half in another. Half the participants will receive the study medicine through an IV and will be given a shot in the muscle without medicine (placebo). The other half will receive the medicine as a shot in the muscle plus an IV without medicine (placebo).