Cognitive impairment in add-on therapy with topiramate

In an open study, 37 epilepsy patients were investigated with regard to cog nitive impairments in anticonvulsant add-on therapy with topiramate (TPM). In addition to a preexisting antiepileptic medication,TPM administration wa s started and increased by 25 mg/week. Cognitive side effects noted by the patient or doctor were assessed by a neuropsychological test battery. In 18 /37 patients (49%), cognitive deficits consisting of impaired concentration , psychomotoric slowing, memory deficits, and dysphasia were observed. The adverse effects became apparent at dosages of 50-575 mg TPM/day (average 21 0 mg). In four patients, they were reversible after reducing the dose of TP M by 25-150 mg/day. In eight patients, the adverse effects led to withdrawa l of TPM. In spite of slow titration, the present study showed a higher fre quency of cognitive side effects under TPM than was previously reported. In some patients,these side effects led to substantial impairments in daily l ife and at work. For early recognition of cognitive impairments, neuropsych ological baseline and follow-up investigations of verbal fluency, psychomot or processing speed, and verbal memory are recommended.