Parenteral phenobarbital in status epilepticus revisited: Mayo Clinic experience

Despite phenobarbital (PB) being a key component in status epilepticus (SE) treatment algorithms for decades, it has fallen out of favor compared to newer nonsedating medications due to potential for respiratory suppression and prolonged sedation. We retrospectively analyzed all nonintubated patients with refractory SE treated with parenteral PB. Forty patients were identified as having received PB in the neurologic intensive care unit at Mayo Clinic over a 7-year period through our pharmacy dispensing database. Patients who received PB for maintenance therapy, those replenishing subtherapeutic levels, those who were already intubated, and those receiving PB for a non-SE indication were excluded. Clinical data, prior treatments, therapeutic response, and outcome were reviewed. Eight patients were identified. Ages ranged from 24 to 77 years (median = 64 years); all had focal SE, and none was comatose. Seizure activity improved acutely following PB administration in seven and stopped in six. Dosages ranged from 5 to 19.8 mg/kg (median = 10.1 mg/kg); none required intubation, and one received supplemental oxygen. Patients received a median of four antiepileptic drugs prior to PB. Median interval between first drug and PB was 23.5 hours. Glasgow Coma Scale score did not change following PB administration. One patient required intervention for hypotension. Moderate-dose parenteral PB was effective in attaining seizure control in a significant proportion of noncomatose refractory SE patients. None required ventilatory support. PB dosages below those in recent guidelines may be sufficient to stop SE without clinically significant cardiopulmonary complications.