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Tiagabine

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Tiagabine, Gabitril

  • See Also
  1. Anticonvulsant
  2. Seizure Disorder
  3. Pregabalin
  4. Gabapentin
  • Indications
  • Adjunctive Therapy
  1. Simple Partial Seizure
  2. Complex Partial Seizure
  3. Bipolar Disorder (not FDA approved)
  4. Anxiety (not FDA approved)
  5. Neuropathic Pain (not FDA approved)
  • Mechanism
  1. Anticonvulsant
  2. GABA Reuptake Inhibitor
    1. Increases inhibition of Neurons
    2. Increases CNS depression
  • Precautions
  1. Adjust dose in hepatic disease
  • Dosing
  1. General
    1. Typically combined with enzyme-inducing anticonvulsants (e.g. Carbamazepine, Phenobarbital, Phenytoin, Primidone)
    2. Decrease starting dose and titration speed when NOT used with an enzyme-inducing anticonvulsant
  2. Adult
    1. Initial: 4 mg orally daily for first week
    2. Increase by 4 to 8 mg/day increments per day weekly (over 6 to 20 weeks)
    3. Divide dose 2 to 4 times daily after first week
    4. Maximum: 56 mg/day divided 2 to 4 times daily
  3. Child (age 12 to 18 years)
    1. Initial: 4 mg orally daily for first week
    2. Increase by 4 mg/day increments per day for first week, then up to 4 to 8 mg/day weekly thereafter (over 6 to 20 weeks)
    3. Divide dose 2 to 4 times daily after first week
    4. Maximum: 32 mg/day divided 2 to 4 times daily
  • Adverse Effects
  • General
  1. Common (Dose related)
    1. Sedation
    2. Dizziness
    3. Lethargy
    4. Tremor
    5. Nervousness
    6. Irritability
    7. Abdominal Pain
    8. Cognitive Impairment
  2. Serious
    1. Neurotoxic in Overdose
    2. Status Epilepticus, New Seizueres, Nonconvulsive Status Epilepticus
      1. May occur when used in patients without Epilepsy
      2. Higher risk in Overdose and when combined with other agents that lower Seizure threshold
  1. Timing
    1. Symptom onset 2 hours at 2 hours after ingestion
    2. Duration up to 24 hours after ingestion
  2. Symptoms
    1. Vomiting
    2. Cardiopulmonary
      1. Tachycardia
      2. Hypertension or Hypotension
      3. Respiratory depression
    3. Neurologic
      1. Somnolence (doses >8 mg in a 6 year old)
      2. Nonconvulsive Status Epilepticus (doses >96 mg in an adult)
      3. Confusion
      4. Agitation
      5. Tremor
      6. Dystonia
      7. Myoclonus
  3. Management
    1. See Unknown Ingestion
    2. Activated Charcoal in early presentations (<1-2 hours after ingestion) and controlled airway
    3. Seizures
      1. Benzodiazepines (preferred first-line)
      2. Barbiturates
      3. Status Epilepticus may require Endotracheal Intubation and Propofol
    4. Disposition
      1. Medically cleared if asymptomatic after 6 hours from time of ingestion
  4. References
    1. Tomaszewski (2024) Crit Dec Emerg Med 38(9):38
  • Safety
  1. Pregnancy Category C
  2. Unknown Safety in Lactation
  • Pharmacokinetics
  1. High oral Bioavailability with peak effect at 1 hour after ingestion
  2. Elimination Half-Life 4.5 to 6 hours
  • Resources
  1. Tiagabine (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=cf97a72e-951e-a7db-a574-adac12a6b189
  • References
  1. (2022) Presc Lett, Resource #361206, Antiseizure Medications
  2. Olson (2020) Clinical Pharmacology, Medmaster Miami, p. 56-7
  3. Hamilton (2020) Tarascon Pocket Pharmacopoeia