Therapeutic monitoring of antiepileptic drugs in comatose patients.

Objective: In this study, we aimed to analyze the trough plasmatic levels (C0) of the antiepileptic drugs (AED) administered by nasogastric tubes (NGT) in comatose patients and to draw up recommendations for therapeutic drug monitoring (TDM) and for the modalities of AED administration by NGT.

Methods: We conducted a retrospective study on comatose patients addressed over six years and 10 months in Clinical Pharmacology for C0 measurement of AED administered by NGT.

Results: In this study, the sex-ratio was 2.38 (44 patients). The patients' median age was 24 years. There was 14.5% of children (≤16 years). Among the 103 samples, C0 measurement concerned valproic acid in 57%, phenobarbital in 28 % and carbamazepine in 15%. Two AED or more were associated in 42% of patients. AED were associated to other drugs in 85% of cases. The AED C0 were subtherapeutic in 71% of cases. C0/Dp lower than recommanded in 65 %. In these samples, 55% presented at least one drug association with the concerned AED. In 45% of the cases, there was no drug association but a non-respect of modalities of AED administration by NGT in patients.

Conclusion:   The drug monitoring is a useful tool to assess drug-drug interactions and to control modalities of AED administration in comatose patients.