tiagabine

[ti-ag´ah-bēn] an anticonvulsant agent used orally as the hydrochloride salt as an adjunct in treatment of seizures" >partial seizures.

tiagabine

(tye-a-ga-been) tiagabine,

Gabitril

(trade name)

Classification

Therapeutic: anticonvulsants
Pregnancy Category: C

Indications

Adjunctive treatment of partial seizures.

Action

Enhances the activity of gamma-aminobutyric acid, an inhibitory neurotransmitter.

Therapeutic effects

Decreased frequency of seizures.

Pharmacokinetics

Absorption: 90% absorbed following oral administration.Distribution: Unknown.Protein Binding: 96%.Metabolism and Excretion: Mostly metabolized by the liver; 2% excreted unchanged in urine.Half-life: Without enzyme-inducing antiepileptic drugs—7–9 hr; with enzyme-inducing antiepileptic drugs—4–7 hr.

Time/action profile (blood levels)

ROUTE	ONSET	PEAK	DURATION
PO	unknown	45 min	unknown

Contraindications/Precautions

Contraindicated in: Hypersensitivity.Use Cautiously in: All patients (may ↑ risk of suicidal thoughts/behaviors);Hepatic impairment (↓ dose/increased interval may be necessary);Patients receiving concurrent non–enzyme-inducing antiepileptic drug therapy such as valproates (may require lower doses and/or slower titration);Using tiagabine for off-label uses or other conditions leading to ↑ levels (may ↑ risk of new onset seizures); Obstetric / Lactation / Pediatric: Pregnancy, lactation, or children <12 yr (safety not established).

Adverse Reactions/Side Effects

Central nervous system

suicidal thoughts (life-threatening)
dizziness (most frequent)
drowsiness (most frequent)
nervousness (most frequent)
weakness (most frequent)
cognitive impairment
confusion
difficulty concentrating
hallucinations
headache
mental depression
personality disorder

Ear, Eye, Nose, Throat

abnormal vision
ear pain
tinnitus

Respiratory

dyspnea
epistaxis

Cardiovascular

chest pain
edema
hypertension
palpitations
syncope
tachycardia

Gastrointestinal

abdominal pain
gingivitis
nausea
stomatitis

Genitourinary

dysmenorrhea
dysuria
metrorrhagia
urinary incontinence

Dermatologic

alopecia
dry skin
rash
sweating

Metabolic

weight gain
weight loss

Musculoskeletal

arthralgia
neck pain

Neurologic

ataxia
tremors

Miscellaneous

allergic reactions
chills
lymphadenopathy

Interactions

Drug-Drug interaction

Carbamazepine, phenytoin, primidone, and phenobarbital induce metabolism and ↓ blood levels; although concurrent therapy is usually necessary, adjustments may be required when altering regimens.

Route/Dosage

Oral (Adults >18 yr) 4 mg once daily initially for 1 wk; may ↑ by 4–8 mg/day at weekly intervals, up to 56 mg/day in 2–4 divided doses.Oral (Children 12–18 yr) 4 mg once daily initially for 1 wk; may ↑ by 4 mg/day after 1 wk, then may ↑ by 4–8 mg/day at weekly intervals, up to 32 mg/day in 2–4 divided doses.

Availability (generic available)

Tablets: 2 mg, 4 mg, 12 mg, 16 mg

Nursing implications

Nursing assessment

Assess location, duration, and characteristics of seizure activity.
Assess mental status. May cause impaired concentration, speech or language problems, confusion, fatigue, and drowsiness. Symptoms may decrease with dose reduction or discontinuation.
Monitor closely for notable changes in behavior that could indicate the emergence or worsening of suicidal thoughts or behavior or depression.

Potential Nursing Diagnoses

Risk for injury (Side Effects)

Implementation

Do not confuse tiagabine with tizanidine.
Oral: Administer with food.
- Discontinue tiagabine gradually. Abrupt discontinuation may cause increase in seizure frequency.

Patient/Family Teaching

Instruct patient to take medication as directed. Take missed doses as soon as possible unless almost time for next dose. Do not double doses. Do not discontinue abruptly; may cause increase in frequency of seizures. Instruct patient to read the Medication Guide before starting and with each Rx refill, changes may occur.
Advise patient to notify health care professional immediately if frequency of seizures increases.
May cause dizziness. Caution patient to avoid driving or activities requiring alertness until response to medication is known. Do not resume driving until physician gives clearance based on control of seizure disorder.
Advise patient and family to notify health care professional if thoughts about suicide or dying, attempts to commit suicide; new or worse depression; new or worse anxiety; feeling very agitated or restless; panic attacks; trouble sleeping; new or worse irritability; acting aggressive; being angry or violent; acting on dangerous impulses; an extreme increase in activity and talking, other unusual changes in behavior or mood occur.
Advise patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken and to consult with health care professional before taking other medications.
Instruct patient to notify health care professional of medication regimen prior to treatment or surgery.
Advise patient to carry identification describing disease process and medication regimen at all times.
Advise patient to notify health care professional if pregnancy is planned or suspected or if breast feeding.

Evaluation/Desired Outcomes

Decrease in the frequency or cessation of seizures.