A single dose of sulthiame induces a selective increase in resting motor threshold in human motor cortex: A transcranial magnetic stimulation study

Sulthiame is a carbonic anhydrase inhibitor that is widely used to treat partial and myoclonic seizures. In 11 healthy adults, we applied transcranial magnetic stimulation (TMS) to the primary motor cortex. Using a cross-over study design, we found that a single oral dose of sulthiame (5 mg/kg) produced a significant increase of resting motor threshold relative to placebo. No other TMS measure of corticomotor excitability was altered after a single dose of sulthiame. The selective increase in motor threshold suggests that sulthiame produces its antiepileptic effect by reducing the axonal excitability of cortical neurons.