Pentobarbital coma (PBC) is a treatment for patients with refractory status epilepticus, but there are currently few guidelines for choosing when to initiate or continue this therapy. To identify potential prognostic factors in this setting, we reviewed the course of 17 adult patients treated with a standardized protocol of PBC for refractory status epilepticus over the past 6 years. PBC was extremely effective in aborting seizures in 16 of 17 patients, but 11 of the patients developed severe hypotension that required therapy with vasopressors. Six of the patients had full recoveries or developed only minimal residual deficits following PBC, two developed severe neurologic deficits, and nine died. Survival was associated with a history of epilepsy, absence of multiorgan failure before or during PBC, age < 40 years, and absence of hypotension requiring vasopressors during PBC. Long-term follow-up in seven of eight survivors (mean, 2.9 years; range, 1 to 5 years) showed that patients' conditions remained stable after discharge from the hospital. Thus, although PBC is effective in controlling ongoing seizures, the therapy frequently leads to significant hypotension. This side effect may be especially troublesome in patients with the negative prognostic indicators identified in this study. These findings highlight the need for alternative approaches in the management of these patients.