List of products in the National Drug Code with proprietary name . Tiagabine is used with other medications to treat certain types of seizures (focal seizures). It works by reducing the spread of seizure activity in the brain. This medication is known as an anticonvulsant or anti-epileptic drug. When tiagabine has been used for conditions other than epilepsy, serious reactions (including seizures in people who have never had them) have occurred. Talk to your doctor for more details.