Section 01 · Monograph
Tiagabine
Reviewed Nov 2026FDA label
GabitrilGABA reuptake inhibitor
- Forms
- Tab: 2, 4, 12, 16mg
- Dose
- 4-56mg/day divided
- MOA
- Blocks GAT-1 GABA transporter
Indications
- Adjunctive therapy for partial seizures in adults and children age 12 years and olderFDA-labeled
Mechanism of Action
- Selectively inhibits the GAT-1 GABA transporter, blocking presynaptic neuronal and glial reuptake of GABA and increasing its availability at postsynaptic GABA-A receptors
Full Dosing
Adult / usual
- Adults on enzyme-inducing AEDs: initiate 4mg once daily; increase by 4-8mg/day at weekly intervals as needed to a usual maintenance of 32-56mg/day in 2-4 divided doses
- Adolescents 12-18 years: similar titration to a maximum of 32mg/day
- Patients not on enzyme-inducing AEDs require lower doses and slower titration due to roughly twofold higher plasma exposure
- Taper gradually over at least several weeks when discontinuing, to reduce risk of seizure exacerbation
Contraindications
- Known hypersensitivity to tiagabine or any component of the formulation
Drug Interactions
- Hepatically metabolized primarily via CYP3A; enzyme-inducing AEDs (carbamazepine, phenytoin, phenobarbital, primidone) increase tiagabine clearance by roughly 60%, lowering levels
- Valproate displaces tiagabine from protein binding, increasing free drug concentration
- Additive CNS depression with alcohol, benzodiazepines, and other sedating drugs
- Highly protein bound — potential for interactions with other highly protein-bound drugs
Adverse Effects
- Common: dizziness, asthenia, somnolence, tremor, nervousness, difficulty concentrating, nausea, diarrhea, abdominal pain
- New-onset seizures and status epilepticus reported in patients without epilepsy, including at low doses (as low as 4mg/day) — tiagabine is not recommended for non-epilepsy use
- Non-convulsive status epilepticus presenting as confusion or behavioral change reported in patients with epilepsy
- Suicidal ideation/behavior (class effect of AEDs)
Monitoring Parameters
- Clinical monitoring for new or worsening seizures, confusion, or spike-wave stupor, particularly in patients with underlying generalized epilepsy syndromes
- Monitor for emerging depression or suicidal ideation
- Avoid use in patients without a diagnosis of epilepsy given the seizure/status epilepticus risk
- Monitor for excessive sedation with concomitant CNS depressants
Pregnancy & Lactation
- Animal studies showed teratogenic effects at maternally toxic doses; human data limited. Use only if potential benefit justifies fetal risk. NAAED Pregnancy Registry enrollment encouraged (1-888-233-2334)
- Unknown whether tiagabine is present in human breast milk; weigh risks/benefits of breastfeeding