Tiagabine is a unique anticonvulsant used largely as an adjunctive agent in therapy of partial seizures in adults or children. Therapy with tiagabine is not associated with serum aminotransferase elevations, and clinically apparent liver injury from tiagabine has not been reported and must be very rare if it occurs at all.
Tiagabine (tye ag' a been) is a selective gamma aminobutyric acid (GABA) reuptake inhibitor that increases synactive concentrations of this major neuroinhibitory transmitter, thus decreasing spread of abnormal neuronal impulses that contribute to seizures. Tiagabine has been shown to be effective both as monotherapy and in combination with other anticonvulsants for partial seizures. Tiagabine was approved for use in epilepsy in the United States in 1997 and is currently used predominantly as adjunctive therapy with other major anticonvulsants for partial seizures. Tiagabine is occasionally used off-label to treat anxiety disorders and neuropathic pain. Tiagabine is available in tablets of 2, 4, 12 and 16 mg in generic formulations and under the brand name of Gabitril. The recommended initial dose in adults is 4 mg once daily, increasing by 4 to 8 mg at weekly intervals based upon clinical response, but not exceeding 56 mg daily. The dose should be increased and tapered gradually. The most common side effects of tiagabine are dose related and include dizziness, somnolence, impaired concentration, nervousness, nausea, weakness and tremor.
Limited data are available on the hepatotoxicity of tiagabine. In clinical trials, therapy with tiagabine was not associated with an increased frequency of serum aminotransferase elevations or liver toxicity. No individual case reports of liver injury from tiagabine have been published and its use has not been associated with hypersensitivity syndromes or autoimmunity.
Mechanism of Injury
The apparent absence of significant hepatotoxicity from tiagabine is despite the fact that it is metabolized by the liver and interacts with the CYP 450 system.
REPRESENTATIVE TRADE NAMES
Tiagabine – Generic, Gabitril®
Product labeling at DailyMed, National Library of Medicine, NIH
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References updated: 11 December 2013
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