Table 2.

Identified and putative modes of action of topiramate peripherally and centrally65,66

Receptor/substrate	Activity	Distribution of activity
1. Gamma aminobutyric acid receptor (α-1 subunit)	Agonist	Central
2. Sodium ion channel (α-1 subunit)	Antagonist	Central and peripheral
3. Carbonic anhydrase 2 and 4	Inhibitor	Systemic
4. Glutamate ionotropic kainate type 1	Antagonist	Central
5. Cytochrome P450 2C19	Inhibitor	Systemic
6. Cytochrome P450 3A4	Inducer	Systemic
7. Calcium α-1 subtype cellularion channel	Antagonist	Central and peripheral
8. ATP activated anion channel (CFTR)	Antagonist	? systemic

Abbreviations: ATP, adenosine triphosphate; CFTR, cystic fibrosis transmembrane condulence regulator.