Abstracts

Topiramate (TPM) is a broad spectrum anti-epileptic drug (AED) often used to treat refractory epilepsy (RE) in adults and children. Recent reports have indicated a potential problem with adverse cognitive effects. In people with intellectual disability (ID) and RE, adverse cognitive effects would be particularly troublesome. We report our experience using TPM in a specialist epilepsy service for people with ID. TPM was added to the treatment of 64 people with ID and RE aged 6-51 years, with follow- up 0.5-5 years. 65% were male. Most had cryptogenic/symptomatic generalised epilepsies (CSGE). Co medications included valproate, lamotrigine, levetiracetam, gabapentin, pregabalin, carbamazepine and phenytion. A low and slow dose titration schedule was used, monitored by community based epilepsy specialist nurses. Adverse events were monitored with a standardized checklist. Seizure frequency was recorded by carers and patients using standardized formats individually designed for each patient. A favourable response led to attempt at reduction of comcomitant medication; lack of response, or patient or carer concern about adverse effects led to TPM withdrawal. Complete seizure control was obtained in 5% of patients. Most achieved a useful reduction in seizure frequency of between 40-80%. A small number reported a shift in seizure spectrum towards milder and/or shorter events. Several patients with tuberous sclerosis (TS), achieved a good effect on seizure control with a final TPM dose of 800ng or higher, with no significant adverse effects. TPM did not have a noticable benefit in tonic seizures. Further analysis of seizure frequency was complicated by factors such as comcomitant withdrawal of other AEDs. In 4 cases, all with cryptogenic/symptomatic generalised epilepsies, TPM was associated with increased seizure frequency and paraictal behavior disturbance, unresponsive to dose reduction but improving on TPM withdrawal. 2 cases were withdrawn due to weight loss; there were no other withdrawals. In several cases carers and patients reported being brighter and more alert. In everyday situations no memory impairment was noted and no patient complained of slowed thinking. A patient with coexisting Prader-Willi syndrome achieved not only improvement in seizure control but also significant improvement in his eating disorder. With slow dose escalation, TPM was well tolerated in people with ID across the age range, and no obvious cognitive effects that interfere with everyday life were noted. Indeed some reported subjective improvement. Some adults with TS may tolerate and benefit from high doses of TPM. Treatment-emergent behavioral effects were associated with paradoxical increase in seizure frequency in some patients; further investigation may reveal an at-risk phenotype. Our pratice continues to support the value of community-based specialist nusre monitoring of dose regimes and adverse events.