Medical Editor: John P. Cunha, DO, FACOEP
Gabitril (tiagabine hydrochloride) is an anti-epileptic medication (anticonvulsant) used alone or in combination with other medications to treat partial seizures in adults and children who are at least 12 years old. Gabitril is available in generic form. Common side effects of Gabitril include:
- inability to concentrate,
- stomach pain,
- sleep problems (insomnia),
- lack of coordination,
- sore throat, or
- weight changes.
Tell your doctor if you have unlikely but serious side effects of Gabitril including:
- increase in seizure activity,
- trouble thinking clearly,
- difficulty forming sentences, or
- severe weakness.
The recommended starting dose of Gabitril for adult patients who are already taking enzyme-inducing antiepilepsy drugs (AEDs) is 4 mg once daily. The total daily dose may be increased by 4 to 8 mg at weekly intervals until clinical response is achieved or, up to 56 mg/day. The starting dose in adolescents 12 to 18 years old is 4 mg once daily, which may be increased by 4 to 8 mg at weekly intervals, up to 32 mg/day. Gabitril may interact with cold or allergy medicines, narcotics, sleeping pills, muscle relaxers, medicines for depression or anxiety, medicines to treat a psychiatric disorder, diet pills, stimulants, or ADHD medications, carbamazepine, divalproex, phenobarbital, phenytoin, primidone, or valproic acid. Tell your doctor all medications you use. Gabitril should be used only when prescribed during pregnancy. It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.
Our Gabitril (tiagabine hydrochloride) Side Effects Drug Center provides a comprehensive view of available drug information on the potential side effects when taking this medication.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Get emergency medical help if you have any of these signs of an allergic reaction: hives; fever; swollen glands; painful sores in or around your eyes or mouth; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any new or worsening symptoms such as: mood or behavior changes, depression, anxiety, or if you feel agitated, hostile, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.
Call your doctor at once if you have any of these serious side effects:
- new or worsened seizures;
- confusion, hallucination;
- problems with speech or vision;
- severe blistering, peeling, and red skin rash;
- fever, chills, body aches, flu symptoms; or
- chest pain, fast heart rate.
Less serious side effects may include:
- dizziness, drowsiness, weakness, tired feeling;
- feeling restless, irritable, or depressed;
- nausea, vomiting, stomach pain, diarrhea;
- trouble concentrating;
- sleep problems (insomnia);
- lack of coordination;
- cough, sore throat; or
- weight changes.
This is not a complete list of side effects and others may occur. Tell your doctor about any unusual or bothersome side effect. You may report side effects to FDA at 1-800-FDA-1088.
Read the entire detailed patient monograph for Gabitril (Tiagabine Hydrochloride)
The most commonly observed adverse events in placebo-controlled, parallel-group, add-on epilepsy trials associated with the use of GABITRIL in combination with other antiepilepsy drugs not seen at an equivalent frequency among placebo-treated patients were dizziness/lightheadedness, asthenia/lack of energy, somnolence, nausea, nervousness/irritability, tremor, abdominal pain, and thinking abnormal/difficulty with concentration or attention.
Approximately 21% of the 2531 patients who received GABITRIL in clinical trials of epilepsy discontinued treatment because of an adverse event. The adverse events most commonly associated with discontinuation were dizziness (1.7%), somnolence (1.6%), depression (1.3%), confusion (1.1%), and asthenia (1.1%).
In Studies 1 and 2 (U.S. studies), the double-blind, placebo-controlled, parallel-group, add-on studies, the proportion of patients who discontinued treatment because of adverse events was 11% for the group treated with GABITRIL and 6% for the placebo group. The most common adverse events considered the primary reason for discontinuation were confusion (1.2%), somnolence (1.0%), and ataxia (1.0%).
Adverse Event Incidence In Controlled Clinical Trials
Table 5 lists treatment-emergent signs and symptoms that occurred in at least 1% of patients treated with GABITRIL for epilepsy participating in parallel-group, placebo-controlled trials and were numerically more common in the GABITRIL group. In these studies, either GABITRIL or placebo was added to the patient’s current antiepilepsy drug therapy. Adverse events were usually mild or moderate in intensity.
The prescriber should be aware that these figures, obtained when GABITRIL was added to concurrent antiepilepsy drug therapy, cannot be used to predict the frequency of adverse events in the course of usual medical practice when patient characteristics and other factors may differ from those prevailing during clinical studies. Similarly, the cited frequencies cannot be directly compared with figures obtained from other clinical investigations involving different treatments, uses, or investigators. An inspection of these frequencies, however, does provide the prescribing physician with one basis to estimate the relative contribution of drug and non-drug factors to the adverse event incidences in the population studied.
Table 5: Treatment-Emergent Adverse Event1 Incidence in Parallel-Group, Placebo-Controlled, Add-On Trials (events in at least 1% of patients treated with GABITRIL and numerically more frequent than in the placebo group)
|Body System/ COSTART||GABITRIL N=494
|Body as a Whole|
|Difficulty with Concentration/Attention*||6||2|
|Difficulty with Memory*||4||3|
|Skin and Appendages|
|1Patients in these add-on studies were receiving one to three concomitant enzyme-inducing antiepilepsy drugs in addition to GABITRIL or placebo. Patients may have reported multiple adverse experiences; thus, patients may be included in more than one category.
* COSTART term substituted with a more clinically descriptive term.
Other events reported by 1% or more of patients treated with GABITRIL but equally or more frequent in the placebo group were: accidental injury, chest pain, constipation, flu syndrome, rhinitis, anorexia, back pain, dry mouth, flatulence, ecchymosis, twitching, fever, amblyopia, conjunctivitis, urinary tract infection, urinary frequency, infection, dyspepsia, gastroenteritis, nausea and vomiting, myalgia, diplopia, headache, anxiety, acne, sinusitis, and incoordination.
Study 1 was a dose-response study including doses of 32 mg and 56 mg. Table 6 shows adverse events reported at a rate of ≥ 5% in at least one GABITRIL group and more frequent than in the placebo group. Among these events, depression, tremor, nervousness, difficulty with concentration/attention, and perhaps asthenia exhibited a positive relationship to dose.
Table 6: Treatment-Emergent Adverse Event Incidence in Study 1† (events in at least 5% of patients treated with GABITRIL 32 or 56 mg and numerically more frequent than in the placebo group)
|Body System/ COSTART Term||GABITRIL 56 mg (N=57) %||GABITRIL 32 mg (N=88) %||Placebo (N=91) %|
|Body as a Whole|
|Hemic and Lymphatic System|
|Difficulty with Concentration/Attention*||14||7||3|
|Urinary Tract Infection||5||0||2|
|† Patients in this study were receiving one to three concomitant enzyme-inducing antiepilepsy drugs in addition to GABITRIL or placebo. Patients may have reported multiple adverse experiences; thus, patients may be included in more than one category.
* COSTART term substituted with a more clinically descriptive term.
The effects of GABITRIL in relation to those of placebo on the incidence of adverse events and the types of adverse events reported were independent of age, weight, and gender. Because only 10% of patients were non-Caucasian in parallel-group, placebo-controlled trials, there is insufficient data to support a statement regarding the distribution of adverse experience reports by race.
Other Adverse Events Observed During All Clinical Trials
GABITRIL has been administered to 2531 patients during all phase 2/3 clinical trials, only some of which were placebo-controlled. During these trials, all adverse events were recorded by the clinical investigators using terminology of their own choosing. To provide a meaningful estimate of the proportion of individuals having adverse events, similar types of events were grouped into a smaller number of standardized categories using modified COSTART dictionary terminology. These categories are used in the listing below. The frequencies presented represent the proportion of the 2531 patients exposed to GABITRIL who experienced events of the type cited on at least one occasion while receiving GABITRIL. All reported events are included except those already listed above, events seen only three times or fewer (unless potentially important), events very unlikely to be drug-related, and those too general to be informative. Events are included without regard to determination of a causal relationship to tiagabine.
Events are further classified within body system categories and enumerated in order of decreasing frequency using the following definitions: frequent adverse events are defined as those occurring in at least 1/100 patients; infrequent adverse events are those occurring in 1/100 to 1/1000 patients; rare events are those occurring in fewer than 1/1000 patients.
Body As A Whole
Infrequent: Angina pectoris, cerebral ischemia, electrocardiogram abnormal, hemorrhage, hypotension, myocardial infarct, pallor, peripheral vascular disorder, phlebitis, postural hypotension, and thrombophlebitis.
Frequent: Gingivitis and stomatitis.
Infrequent: Abnormal stools, cholecystitis, cholelithiasis, dysphagia, eructation, esophagitis, fecal incontinence, gastritis, gastrointestinal hemorrhage, glossitis, gum hyperplasia, hepatomegaly, increased salivation, liver function tests abnormal, melena, periodontal abscess, rectal hemorrhage, thirst, tooth caries, and ulcerative stomatitis.
Hemic And Lymphatic System
Metabolic And Nutritional
Frequent: Edema, peripheral edema, weight gain, and weight loss.
Frequent: Depersonalization, dysarthria, euphoria, hallucination, hyperkinesia, hypertonia, hypesthesia, hypokinesia, hypotonia, migraine, myoclonus, paranoid reaction, personality disorder, reflexes decreased, stupor, twitching, and vertigo.
Infrequent: Abnormal dreams, apathy, choreoathetosis, circumoral paresthesia, CNS neoplasm, coma, delusions, dry mouth, dystonia, encephalopathy, hemiplegia, leg cramps, libido increased, libido decreased, movement disorder, neuritis, neurosis, paralysis, peripheral neuritis, psychosis, reflexes increased, and urinary retention.
Skin And Appendages
Frequent: Alopecia, dry skin, and sweating.
Infrequent: Contact dermatitis, eczema, exfoliative dermatitis, furunculosis, herpes simplex, herpes zoster, hirsutism, maculopapular rash, psoriasis, skin benign neoplasm, skin carcinoma, skin discolorations, skin nodules, skin ulcer, subcutaneous nodule, urticaria, and vesiculobullous rash.
Infrequent: Abortion, amenorrhea, breast enlargement, breast pain, cystitis, fibrocystic breast, hematuria, impotence, kidney failure, menorrhagia, nocturia, papanicolaou smear suspicious, polyuria, pyelonephritis, salpingitis, urethritis, urinary urgency, and vaginal hemorrhage.
The following adverse reactions have been identified during postapproval use of GABITRIL. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
Skin and subcutaneous tissue disorders: bullous dermatitis
Eye disorders: vision blurred
Read the entire FDA prescribing information for Gabitril (Tiagabine Hydrochloride)
© Gabitril Patient Information is supplied by Cerner Multum, Inc. and Gabitril Consumer information is supplied by First Databank, Inc., used under license and subject to their respective copyrights.