Tiagabine as add-on therapy may be more effective with valproic acid--open label, multicentre study of patients with focal epilepsy.

The aim of the current study was to review the efficacy of tiagabine (TGB) as add-on therapy in patients with drug-resistant focal epilepsy under normal daily clinical practice, and try to identify those who had improvement. This was an open multicentre study conducted in Poland. A group of 330 patients were analysed. Patients received TGB up to 30-50 mg/day with adjustment within the therapeutic range and titration period. For statistical evaluation chi-square test and logistic analysis were used. At the 16-week follow-up visit, 71.4% patients were reported as responders, i.e. had a 50% or greater decrease in seizure frequency compared with baseline (P<0.001). One-third of patients were seizure-free at 16-week evaluation (P<0.001). The beneficial effect of TGB on seizure reduction was most marked in patients with partial seizures (P<0.001). Patients who used valproic acid (mean dose 1307 mg/day) had 61-85% higher chances for disappearance of seizures or reduction of their number by 50% or more. Patients who used carbamazepine (mean dose 800 mg/day) at a dose 1000 mg or higher mg/day had twice lower chance for reduction of seizures by 50% or more (OR=0.45; 95 CI 0.25-0.82). There was no statistical impact of sex, age and aetiology on probability of therapeutic effect.