Several open studies of tiagabine were conducted to evaluate it as an add-on therapy in partial seizures. Several controlled clinical trials were also conducted with tiagabine as an add-on therapy.
A 3-times daily regimen of tiagabine was evaluated as add-on therapy in a multicenter, double-blind, parallel-group, placebo-controlled trial in patients with refractory partial seizures (Kalviainen et al 1998). Tiagabine was generally well tolerated and demonstrated efficacy for the treatment of refractory partial seizures. Another double-blind, placebo-controlled, crossover study of tiagabine showed that it was significantly better than placebo in terms of seizure rate reduction and was generally well tolerated in patients with difficult to control seizures (Crawford et al 2001).
Results of a randomized, open-label study of tiagabine suggest that during titration, tiagabine is better tolerated with 3-times daily dosing, but during long term maintenance, a 3-times daily schedule is as effective and well tolerated as twice daily dosing (Arroyo et al 2005).
An open-label, multicenter study of patients with focal epilepsy has shown that tiagabine as add-on therapy may be more effective when combined with valproic acid (Jedrzejczak 2005).