Drug description:

Topiramate is a dioxolopyrans derivative acts as an anticonvulsant agent.
TPM is currently used as an additive treatment for adult patients with refractory partial and secondarily generalized seizure, and primary generalized tonic-clonic seizures. Topiramate can be used for adjunctive therapy in children aged 2 years and above, adolescents and adults with partial onset seizures with or without secondary generalization or primary generalized tonic-clonic seizures and for the treatment of seizures associated with Lennox-Gastaut syndrome. Topiramate is effecive in treating adults newly diagnosed epilepsy.
It is formulated as tablets for oral route of administration.

Mechanism of action:

Topiramate blocks the action potentials elicited repetitively by a sustained depolarization of the neurons in a time-dependent manner, suggesting a state-dependent sodium channel (voltage dependent sodium channel) blocking action. The frequency at which GABA-activated chloride channels (GABAA receptors) is increased by Topiramate and enhances the ability of GABA to induce a flux of chloride ions into neurons, suggesting that topiramate potentiates the activity of this inhibitory neurotransmitter.
Topiramate antagonizes the ability of kainate to activate the kainate/AMPA subtype of excitatory amino acid (glutamate) receptor, but had no apparent effect on the activity of N-methyl-D-aspartate (NMDA) at the NMDA receptor subtype and it also inhibits the carbonic anhydrase enzyme, particularly isozymes II and IV.