Topiramate is a dioxolopyrans derivative acts as an anticonvulsant agent.
Topiramate is indicated for monotherapy in adults, adolescents and children over 6 years of age with partial seizures with or without secondary generalized seizures, and primary generalized tonic-clonic seizures. Topiramate is indicated 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 indicated in adults for the prophylaxis of migraine headache after careful evaluation of possible alternative treatment options.
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. Topiramate increased the frequency at which GABA-activated chloride channels (GABAA receptors) 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.