Tiagabine


Concise Prescribing Info
Indications/Uses
Adjunct in refractory partial seizures.
Dosage/Direction for Use
Adult : PO 5 mg twice daily for 1 wk, may increase slowly. Maintenance: 15-30 mg/day in 3 divided doses.
Dosage Details
Oral
Adjunct in refractory partial seizures
Adult: 5 mg bid for 1 wk, may increase on a wkly basis by increments of 5-10 mg. Usual maintenance dose: 15-30 mg daily, in 3 divided doses; higher doses of 30-45 mg daily may be used in patients on enzyme-inducing antiepileptics.
Hepatic Impairment
Mild-moderate: Initial maintenance dose of 5-10 mg daily. Avoid in severe impairment.
Administration
Should be taken with food.
Special Precautions
Discontinue treatment if there is sign of hypersensitivity. Hepatic impairment. Safety and efficacy have not been established in children <12 yr. Avoid abrupt withdrawal. Monitor for any sign/symptom (e.g. behaviour changes, anxiety, depression) of suicidal tendency or ideation. Pregnancy and lactation.
Adverse Reactions
CNS depression, dizziness, nervousness, somnolence. Nausea, diarrhoea, abdominal pain, tremor, weakness, chest pain, oedema, hypertension, palpitation, peripheral oedema, syncope, tachycardia, vasodilation.
Potentially Fatal: Severe reactions, including toxic epidermal necrolysis and Stevens-Johnson syndrome.
Overdosage
Symptoms include somnolence, impaired consciousness, agitation, confusion, speech difficulty, hostility, depression, weakness, and myoclonus. There is no specific antidote. Unabsorbed drug may be removed by emesis or gastric lavage. General supportive care including monitoring of vital signs and observation of clinical status of the patient should be administered when needed.
Drug Interactions
Increased sedation when used with other sedative drugs or ethanol. Valproate may increase free tiagabine levels. Concurrent use with CYP3A4 inhibitors (e.g. azole antifungals, clarithromycin, diclofenac, doxycycline, erythromycin, imatinib, isoniazid, nefazodone, nicardipine, propofol, protease inhibitors, quinidine, telithromycin and verapamil) may increase levels of tiagabine. CYP3A4 inducers (e.g. aminoglutethimide, carbamazepine, nafcillin, nevirapine, phenobarbital, phenytoin and rifamycins) may decrease levels of tiagabine.
Food Interaction
St John's wort may decrease tiagabine levels. Avoid valerian, kava kava, gotu kola (may increase CNS depression).
Action
Description: Tiagabine is a nipecotic acid derivative that is used as an adjunct in the treatment of partial seizures. The exact mechanism not known but in vitro experiments show that it increases the activity of gamma aminobutyric acid (GABA) by binding to the GABA uptake carrier, thus inhibiting the uptake of GABA into presynaptic neurons, resulting in an increased amount of GABA to be available to postsynaptic neurons.
Pharmacokinetics:
Absorption: Readily absorbed after oral admin.
Distribution: Widely distributed throughout the body. Plasma protein binding: 96%.
Metabolism: Largely metabolised in the liver.
Excretion: Excreted as metabolites in the faeces and, to a lesser extent, in the urine. <2% of a dose is eliminated as unchanged drug. Elimination half-life: 7-9 hr.
Storage
Store at 20-25°C.
MIMS Class
Disclaimer: This information is independently developed by MIMS based on Tiagabine from various references and is provided for your reference only. Therapeutic uses, prescribing information and product availability may vary between countries. Please refer to MIMS Product Monographs for specific and locally approved prescribing information. Although great effort has been made to ensure content accuracy, MIMS shall not be held responsible or liable for any claims or damages arising from the use or misuse of the information contained herein, its contents or omissions, or otherwise. Copyright © 2020 MIMS. All rights reserved. Powered by MIMS.com
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