Effects of topiramate on memory performance on the intracarotid amobarbital (Wada) test.

We evaluated the effects of topiramate (TPM) on memory function in the intracarotid amobarbital (Wada) test in nine patients with mesial temporal lobe epilepsy (MTLE) whose antiepileptic drugs (AEDs) included TPM and compared their scores with those of 16 patients with MTLE on AEDs not including TPM. Sodium amobarbital was injected first into the hemisphere ipsilateral to the seizure focus and then into a contralateral site, and the patients were tested for naming and memorization. There was no statistical difference in percentage memory scores between the two patient groups following the contralateral injection. After the ipsilateral injection, however, TPM patients had significantly lower percentage memory scores compared with non-TPM patients (P < 0.02). We conclude that a possible adverse effect of TPM on memory performance should be considered when evaluating the Wada test memory scores of patients on TPM therapy.