A new study has indicated that the antiepileptic drug (AED) topiramate could have some negative cognitive side effects for epilepsy patients who are affected by intellectual disabilities (ID).

Observational research carried out by the Bethel Epilepsy Centre and Society for Epilepsy Research in Germany aimed to establish whether the drug causes cognitive adverse events among patients in this group.

Topiramate is commonly used in persons with intellectual disabilities and is often an effective therapy option. However, it is also known that a high proportion of patients treated with the AED experience cognitive adverse events, especially in terms of verbal fluency, memory spans and working memory.

This study was carried out due to a lack of existing research systematically assessing the risk of these side effects specifically among patients with ID. This may be because of the fact that many of these patients are not able to follow test instructions, or that neuropsychological instruments are not validated for this group, which means that cognitive deterioration in patients with ID may often be overlooked.

For the research, 26 consecutive patients with epilepsy and ID were assessed who had undergone neuropsychological examinations as part of routine practice, both before and after the introduction of topiramate into the therapeutic regimen, or before and after the withdrawal of the drug.

It was shown that use of the AED was associated with reduced cognitive speed, verbal memory, verbal fluency and flexibility compared to examinations without topiramate.

The researchers concluded: “Our study indicates that topiramate in persons with epilepsy and intellectual disability may lead to cognitive adverse events comparable to those in persons with normal intelligence. Neuropsychological testing is mandatory in order not to miss cognitive adverse events that might severely impair quality of life.”

Sold under the brand name Topamax, the drug is well-established in the treatment of both epilepsy and migraines. This new research could help inform decision-making around its future usage.

Posted by Bob Jones

Publication abstract (Epilepsy & Behavior):

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