Background and Importance Status epilepticus (SE)is associated with high morbimortality. Early treatment has been demonstrated to decrease the risk of death and sequelae. When first-line drugs cannot solve SE, therapeutic coma should be initiated with midazolam(most used), propofol, thiobarbital or phenobarbital (better therapeutic profile with low evidence, especially in paediatrics) are used for this practice.

Aim and Objectives Describing high-dose phenobarbital (HD-PHB) used in therapeutic coma in paediatric refractory SE and their side effects. Exposing the pharmacokinetic monitoring to achieve barbiturate coma (BC).

Material and Methods Observational retrospective study of a third-level paediatric hospital conducted between 2012-2022. 51 paediatric intensive care unit (PICU)’s patients who received intravenous phenobarbital treatment were included, 6 of them underwent BC. Variables collected were age, weight, number of previous antiepileptic treatments, loading and maintenance doses of phenobarbital, phenobarbital plasmatic levels during coma, BC days until resolution of SE, exitus and adverse effects of HD-PHB.All data were obtained from the clinical history programme .

Results 51 patients were included, of them 6 (median 9 years [0.2-14.5] and 20.2kg) were treated with HD-PHB to achieve BC due to the presence of seizures refractory to propofol or midazolam: 5 had a previous history of epilepsy, treated with a median of 3 antiepileptics at home. The resolution was evaluated by encephalogram. The initial phenobarbital doses used to achieve BC were 60mg/kg/day [50-125]. Reported phenobarbital plasma levels achieved in the BC phase were 943µmol/L [743-1883]. Patients were in coma for a median of 4.5 days [1-6] and in all of them a suppression burst was observed in the encephalogram. Glasgow Scale before coma was 9[7-13] and during coma was 3[2-5]. After resolution of the status, tapering regimen was carried out until phenobarbital plasma levels were below 350µmol/L and a maintenance dose (10mg/kg/12h [2-20]) was continued. The adverse effects reported were haematological in 5 patients(decrease in haemoglobin and haematocrit levels) and hepatic in 2 patients (elevation of transaminases levels). One patient died before 6 months post-coma.

Conclusion and Relevance HD-PHB seems to be an effective therapeutic procedure in paediatric refractory SE. Pharmacokinetics is important to ensure the maintenance of coma and avoid toxicity. More pharmacokinetic studies are needed to establish a population model and clear protocols for BC management.

Conflict of Interest No conflict of interest