Bridge Therapy with Intravenous Antiepileptic for Optimizing Oral Antiepileptic Drugs

A seven year old patient with intractable epilepsy was admitted to our hospital. We used intravenous (IV) antiepileptic drug (AED) regimen to optimize the oral AEDs by adding newer AEDs, which have been reported to be beneficial when compared to older AEDs in controlling seizures. The patient was diagnosed with myoclonic, absence, astatic and tonic seizures. He was already on six oral AEDs, and we speculated that his seizures were intractable as he was on AED polytherapy. Therefore we substituted with newer AEDs and simultaneously treated with an IV AED as a base therapy (AED adjustment). The patient’s EEG was exacerbated when slow infusion Midazolam (MDL) at 0.1 mg/kg/dose and Phenobarbital at 10 mg/kg/dose was used. Fosphenytoin sodium hydrate (fos-PHT) was the only IV AED which improved the patient’s EEG. He had no seizures with IV fos-PHT at 10 mg/kg/day. We continued with treatment with Sodium valproate and stopped other five oral AEDs and did not notice any withdrawal effects or seizure exacerbation. Slow infusion of MDL (0.1 mg/kg/dose) improved his EEG significantly in a week, so we decided to stop fos-PHT and continue IV MDL 0.1 mg/kg/hr. Later, we gradually decreased the dose of MDL and choose oral AEDs in accordance with his seizure type. This reduced his oral AEDs to three.
This case suggests that: 1) use of IV AED as a base therapy, can adjust patients’ AED treatment safely in a short period; and 2) In this particular case, newer AEDs was ineffective when administered along with AED polytherapy. Reducing the number oral AEDs administered to patients is a crucial goal when reassessing their oral AED regimen.