ABSTRACTS may be used in Children and infants during status epilepticus when IV access is not available. The IO and IV routes of diazepam administration were compared in a pentylenetetrazol (PTZ) seizure model. Ten domestic swine weighing 14 to 19 kg were anesthetized with ketamine 20 mg/kg IM and alpha-chloralose 25 mg/kg IV and were ventilated with a respirator on 35% 02. Blood pressure and lead II ECG were monitored throughout the experiment. Electrocortical activity was recorded directly from the brain with platinum electrodes. All animals were given PTZ 100 mg/kg IV to induce seizure activity, and they received diazepam 0.l mg/kg IV 1 minute after the onset of seizure through a peripheral IV (n = 5) or through an 18-gauge needle in the proximal tibia IO (n = 5). Blood samples were drawn for determination of diazepam levels at 1, 2, 5, 10, 15, and 20 minutes after diazepam administration. Control heart rates and mean arterial blood pressure were similar for the two groups: 240.6 Β± 11.1 and 238.7 + 7.0 beats/minute, and 128.6 -+ 12.0 and 127.2 Β± 8.3 mm Hg for IV and IO, respectively, The time to onset of seizure was 20.2 Β± 3.02 seconds and 16.4 Β± 2.5 seconds for the IV and IO routes, respectively (P > .05). IV diazepam suppressed seizure activity in all IV animals in 38.4 + 10.8 seconds, while IO diazepam stopped it in 4 IO animals in 53.2 +_ 29.3 seconds. One IO animal had increased ictal activity for 12 minutes. Serum diazepam levels (ng/mL) and standard error for the IV and IO groups were as follows: