[6] The American Academy of Sleep Medicine's 2017 clinical practice guidelines recommended against the use of tiagabine in the treatment of insomnia due to poor effectiveness and very low quality of evidence.

[8] Other side effects that have been observed with a rate of statistical significance relative to placebo include asthenia, somnolence, nervousness, memory impairment, tremor, headache, diarrhea, and depression.

[2] Tiagabine overdose can produce neurological symptoms such as lethargy, single or multiple seizures, status epilepticus, coma, confusion, agitation, tremors, dizziness, dystonias/abnormal posturing, and hallucinations, as well as respiratory depression, tachycardia, hypertension, and hypotension.

Although the exact mechanism by which Tiagabine exerts its antiseizure effect is unknown, it is thought to be related to its ability to increase the activity of gamma aminobutyric acid (GABA), the central nervous system's major inhibitory neurotransmitter.

Seizure frequency, liver function tests, suicidality[16] Tiagabine was discovered at Novo Nordisk in Denmark in 1988 by a team of medicinal chemists and pharmacologists under the general direction of Claus Bræstrup.