Home Drug Guide Tiagabine Hydrochloride

Drug Guide

Generic Name

Tiagabine Hydrochloride

Brand Names Gabitril

Classification

Therapeutic: Anticonvulsant, Antiepileptic

Pharmacological: GABA reuptake inhibitor

FDA Approved Indications

Partial seizures (with or without secondary generalization) in adults and children aged 12 years and older

Mechanism of Action

Tiagabine inhibits the reuptake of gamma-aminobutyric acid (GABA) into neurons and glia, increasing GABA concentrations in the synaptic cleft and enhancing GABAergic neurotransmission, which helps suppress neuronal excitability.

Dosage and Administration

Adult: Start with 4 mg once daily at bedtime; may be increased in 3- to 4-week intervals up to a maximum of 56 mg/day, divided into 2 doses.

Pediatric: Not established for children under 12 years due to limited data.

Geriatric: No specific dosage adjustment recommended; start at lower doses given age-related changes in metabolism.

Renal Impairment: No specific adjustment; monitor closely.

Hepatic Impairment: Use with caution; start at lower doses because of decreased metabolism.

Pharmacokinetics

Absorption: Well absorbed after oral administration, with peak plasma concentrations occurring within about 1 hour.

Distribution: Widely distributed; approximately 96% bound to plasma proteins.

Metabolism: Primarily hepatic via CYP3A4; undergoes minimal first-pass metabolism.

Excretion: Excreted mainly in feces (approximately 60%) and urine (approximately 27%).

Half Life: About 7 hours in healthy individuals.

Contraindications

Hypersensitivity to tiagabine or any component of the formulation.

Precautions

History of depression, suicidality, or other psychiatric disorders; increased risk of suicidal ideation or behavior.
Use with caution in patients with hepatic impairment; monitor for signs of neurotoxicity and sedation.
Monitor for signs of worsening seizure control.

Adverse Reactions - Common

Dizziness (Common)
Somnolence (Common)
Feeling of weakness or tiredness (Common)
Nausea (Common)

Adverse Reactions - Serious

Seizures or status epilepticus (possible discontinuation-related rebound) (Less common)
Psychiatric symptoms such as depression or suicidal thoughts (Rare)
Severe allergic reactions (Rare)

Drug-Drug Interactions

CYP3A4 inducers or inhibitors (e.g., carbamazepine, erythromycin) which can alter tiagabine levels.
Other central nervous system depressants that may enhance sedative effects.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor frequency and severity of seizures, depression, suicidal ideation, and neurotoxicity.

Diagnoses:

Risk for injury related to dizziness or somnolence.
Impaired cognitive or physical functioning.

Implementation: Administer with food to reduce gastrointestinal irritation. Educate patient on avoiding alcohol and CNS depressants.

Evaluation: Assess for reduction in seizure frequency and monitor for adverse effects.

Patient/Family Teaching

Take medication exactly as prescribed.
Report new or worsening depression, suicidal thoughts, or mood changes.
Caution with activities requiring alertness until side effects are known.
Do not discontinue abruptly to avoid seizure exacerbation.

Special Considerations

Black Box Warnings:

Risk of status epilepticus if discontinued abruptly.
Increased risk of suicidal thoughts and behaviors.

Genetic Factors: Variations in CYP3A4 enzyme activity may affect drug levels.

Lab Test Interference: None known.

Overdose Management

Signs/Symptoms: Dizziness, drowsiness, hypotension, coma.

Treatment: Supportive care, activated charcoal if ingestion recent, and monitoring of vital signs. Consider seizure precautions. No specific antidote.

Storage and Handling

Storage: Store at room temperature, away from moisture and heat.

Stability: Stable under recommended storage conditions for the shelf life specified on the packaging.