Tiagabine Hydrochloride (Page 6 of 8)

Postmarketing Reports

The following adverse reactions have been identified during postapproval use of tiagabine HCl. 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

DRUG ABUSE AND DEPENDENCE

The abuse and dependence potential of tiagabine HCl have not been evaluated in human studies.

OVERDOSAGE

Human Overdose Experience: Human experience of acute overdose with tiagabine HCl is limited. Eleven patients in clinical trials took single doses of tiagabine HCl up to 800 mg. All patients fully recovered, usually within one day. The most common symptoms reported after overdose included somnolence, impaired consciousness, agitation, confusion, speech difficulty, hostility, depression, weakness, and myoclonus. One patient who ingested a single dose of 400 mg experienced generalized tonic-clonic status epilepticus, which responded to intravenous phenobarbital.

From post-marketing experience, reports of overdose involving tiagabine HCl alone have included cases in which patients required intubation and ventilatory support as part of the management of their status epilepticus. Overdoses involving multiple drugs, including tiagabine HCl, have resulted in fatal outcomes. Symptoms most often accompanying tiagabine HCl overdose, alone or in combination with other drugs, have included: seizures including status epilepticus in patients with and without underlying seizure disorders, nonconvulsive status epilepticus, respiratory arrest, coma, loss of consciousness, ataxia, dizziness, confusion, somnolence, drowsiness, impaired speech, aggression, agitation, lethargy, myoclonus, spike wave stupor, encephalopathy, amnesia, dyskinesia, tremors, disorientation, psychotic disorder, vomiting, hostility, and temporary paralysis. Respiratory depression was seen in a number of patients, including children, in the context of seizures.

Management of Overdose: There is no specific antidote for overdose with tiagabine HCl. If indicated, elimination of unabsorbed drug should be achieved by emesis or gastric lavage; usual precautions should be observed to maintain the airway. General supportive care of the patient is indicated including monitoring of vital signs and observation of clinical status of the patient. Since tiagabine is mostly metabolized by the liver and is highly protein bound, dialysis is unlikely to be beneficial. A Certified Poison Control Center should be consulted for up to date information on the management of overdose with tiagabine HCl.

DOSAGE AND ADMINISTRATION

General:

The blood level of tiagabine obtained after a given dose depends on whether the patient also is receiving a drug that induces the metabolism of tiagabine. The presence of an inducer means that the attained blood level will be substantially reduced. Dosing should take the presence of concomitant medications into account.

Tiagabine HCl is recommended as adjunctive therapy for the treatment of partial seizures in patients 12 years and older.

The following dosing recommendations apply to all patients taking tiagabine HCl:

  • Tiagabine HCl is given orally and should be taken with food.
  • Do not use a loading dose of tiagabine HCl.
  • Dose titration: Rapid escalation and/or large dose increments of tiagabine HCl should not be used.
  • Missed dose(s): If the patient forgets to take the prescribed dose of tiagabine HCl at the scheduled time, the patient should not attempt to make up for the missed dose by increasing the next dose. If a patient has missed multiple doses, patient should refer back to his or her physician for possible re-titration as clinically indicated.
  • Dosage adjustment of tiagabine HCl should be considered whenever a change in patient’s enzyme-inducing status occurs as a result of the addition, discontinuation, or dose change of the enzyme-inducing agent.

Induced Adults and Adolescents 12 Years or Older: The following dosing recommendations apply to patients who are already taking enzyme-inducing antiepilepsy drugs (AEDs) (e.g., carbamazepine, phenytoin, primidone, and phenobarbital). Such patients are considered induced patients when administering tiagabine HCl.

In adolescents 12 to 18 years old, tiagabine HCl should be initiated at 4 mg once daily. Modification of concomitant antiepilepsy drugs is not necessary, unless clinically indicated. The total daily dose of tiagabine HCl may be increased by 4 mg at the beginning of Week 2. Thereafter, the total daily dose may be increased by 4 to 8 mg at weekly intervals until clinical response is achieved or up to 32 mg/day. The total daily dose should be given in divided doses two to four times daily. Doses above 32 mg/day have been tolerated in a small number of adolescent patients for a relatively short duration.

In adults, tiagabine HCl should be initiated at 4 mg once daily. Modification of concomitant antiepilepsy drugs is not necessary, unless clinically indicated. The total daily dose of tiagabine HCl may be increased by 4 to 8 mg at weekly intervals until clinical response is achieved or, up to 56 mg/day. The total daily dose should be given in divided doses two to four times daily. Doses above 56 mg/day have not been systematically evaluated in adequate and well-controlled clinical trials.

Experience is limited in patients taking total daily doses above 32 mg/day using twice daily dosing. A typical dosing titration regimen for patients taking enzyme-inducing AEDs (induced patients) is provided in Table 7.

Table 7: Typical Dosing Titration Regimen for Patients Already Taking Enzyme-Inducing AEDs

Initiation and Titration Schedule

Total Daily Dose

Week 1

Initiate at 4 mg once daily

4 mg/day

Week 2

Increase total daily dose by 4 mg

8 mg/day

(in two divided doses)

Week 3

Increase total daily dose by 4 mg

12 mg/day

(in three divided doses)

Week 4

Increase total daily dose by 4 mg

16 mg/day

(in two to four divided doses)

Week 5

Increase total daily dose by 4 to 8 mg

20 to 24 mg/day

(in two to four divided doses)

Week 6

Increase total daily dose by 4 to 8 mg

24 to 32 mg/day

(in two to four divided doses)

Usual Adult Maintenance Dose in Induced Patients:

32 to 56 mg/day in two to four divided doses

Non-Induced Adults and Adolescents 12 Years or Older: The following dosing recommendations apply to patients who are taking only non-enzyme-inducing AEDs. Such patients are considered non-induced patients:

Following a given dose of tiagabine HCl, the estimated plasma concentration in the non-induced patients is more than twice that in patients receiving enzyme-inducing agents. Use in non-induced patients requires lower doses of tiagabine HCl. These patients may also require a slower titration of tiagabine HCl compared to that of induced patients (see CLINICAL PHARMACOLOGY, Pharmacokinetics and PRECAUTIONS, General, Use in Non-Induced Patients).

HOW SUPPLIED

Tiagabine HCl tablets are available in four dosage strengths.

2 mg orange-peach, round tablets, debossed with figure05 on one side and 402 on the opposite side, are available in bottles of 30 (NDC 0093-5030-56).

4 mg yellow, round tablets, debossed with figure06 on one side and 404 on the opposite side, are available in bottles of 30 (NDC 0093-5031-56).

12 mg green, ovaloid tablets, debossed with image07 on one side and 412 on the opposite side, are available in bottles of 30 (NDC 0093-8072-56).

16 mg blue, ovaloid tablets, debossed with image08 on one side and 416 on the opposite side, are available in bottles of 30 (NDC 0093-8076-56).

Recommended Storage: Store tablets at controlled room temperature, between 20-25°C (68-77°F). See USP. Protect from light and moisture.

All MedLibrary.org resources are included in as near-original form as possible, meaning that the information from the original provider has been rendered here with only typographical or stylistic modifications and not with any substantive alterations of content, meaning or intent.

This site is provided for educational and informational purposes only, in accordance with our Terms of Use, and is not intended as a substitute for the advice of a medical doctor, nurse, nurse practitioner or other qualified health professional.

Privacy Policy | Copyright © 2022. All Rights Reserved.