Thiamylal serum concentration for refractory convulsive status epilepticus while associated decreased concentrations of concomitant antiepileptics: a case report

• Published in: Journal of pharmaceutical health care and sciences 2024-07, Vol.10 (1), p.39-4, Article 39
• Main Authors: Oda, Kazutaka, Katanoda, Tomomi, Arakaki, Hitomi, Katsume, Taiki, Matsuyama, Kaho, Jono, Hirofumi, Saito, Hideyuki
• Format: Article
• Language: English
• Subjects: Anticonvulsants; Carbamazepine; Care and treatment; Cytochrome P450; Refractory status epilepticus; Seizures (Medicine); Status epilepticus; Therapeutic drug monitoring; Thiamylal
• ISSN: 2055-0294; 2055-0294
• DOI: 10.1186/s40780-024-00362-w

Treating refractory status epilepticus (RSE) remains a challenge. Thiamylal can be used as a second- or third-line treatment; however, its potential to induce cytochrome P450 (CYP) activity may reduce the concentration of antiepileptic drugs (AEDs) administered prior to thiamylal. This report details a case of RSE patient treated with thiamylal, with monitored concentrations of thiamylal and other AEDs. A 72-year-old healthy man developed RSE. Despite the administration of various AEDs, his seizures were not resolved. Thiamylal was then administered at an initial bolus dose of 2.1 mg/kg, followed by a continuous infusion of 4.2-5.2 mg/kg/h. The initial thiamylal concentration was observed at 7.8 μg/mL, increasing to 35.2 μg/mL before decreasing after dose reduction and cessation. Concurrently, the concentration of concomitant carbamazepine decreased from 5.59 μg/mL to 2.1 μg/mL and recovered as thiamylal concentration decreased. Lesser impacts were noted for other AEDs. This case report underscored the efficacy of thiamylal in treating RSE. However, it also highlighted the need for clinicians to closely monitor the concentrations of concurrent AEDs, especially carbamazepine, during thiamylal therapy.