Use in girls with Rett s syndrome reported not only improved seizure control but also improved function and well-being, although how these were assessed was not clear. The upper level of clinically tolerable levels has not been established. These two new AEDs have not been approved yet in the United States. Vigabatrin binds to GABA-transaminase, inhibiting the first step in GABA degradation. In addition, the drug may have significant behavioral effects.
Clinical trials continue.
Topiramate is a weak carbonic anhydrase inhibitor with a number of mechanisms of action.