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Sabril Generic Name & Formulations
Legal Class
Rx
General Description
Vigabatrin 500mg; tabs.
Pharmacological Class
Antiepileptic.
See Also
How Supplied
Tabs—100; Pwd packets—50
Manufacturer
Generic Availability
NO
Mechanism of Action
The mechanism of vigabatrin's anti-seizure effect is unknown, but it is believed to act as an irreversible inhibitor of γ-aminobutyric acid transaminase (GABA-T) resulting in elevated GABA levels in the CNS. GABA-T is the enzyme responsible for the metabolism of the inhibitory neurotransmitter GABA.
Sabril Indications
Indications
Adjunctive therapy in patients ≥2yrs of age with refractory complex partial seizures (CPS) who have inadequately responded to several alternative treatments and for whom the potential benefits outweigh the risk of vision loss. Not a first line agent for CPS. Monotherapy for infantile spasms (IS) in patients 1month–2yrs of age, when the potential benefits outweigh the risk of vision loss.
Sabril Dosage and Administration
Adult
≥17yrs: initially 500mg twice daily; may be increased weekly by 500mg/day to maintenance 1.5g twice daily. CrCl >50–80mL/min: reduce dose by 25%; CrCl >30–50mL/min: reduce dose by 50%; CrCl >10–30mL/min: reduce dose by 75%. Reevaluate periodically. Withdraw gradually (reduce by 1g/day at weekly intervals).
Children
CPS: <2yrs: not established. 2–16yrs: 10–15kg: initially 175mg twice daily; may be increased weekly to maintenance 525mg twice daily. >15–20kg: initially 225mg twice daily (maintenance 650mg twice daily). >20–25kg: initially 250mg twice daily (maintenance 750mg twice daily). 25–60kg: initially 250mg twice daily (maintenance 1g twice daily). >60kg: use adult dosing. CrCl >50–80mL/min: reduce dose by 25%; CrCl >30–50mL/min: reduce dose by 50%; CrCl >10–30mL/min: reduce dose by 75%. Reevaluate periodically. Withdraw gradually (reduce daily dose by ⅓ per week for 3 weeks). IS: <1month: not recommended. 1month–2yrs: use oral soln. Initially 50mg/kg/day (given in 2 divided doses); may titrate by 25–50mg/kg/day at 3-day intervals up to max 150mg/kg/day (75mg/kg twice daily). Withdraw gradually (reduce by 25–50mg/kg/day every 3–4 days).
Sabril Contraindications
Not Applicable
Sabril Boxed Warnings
Boxed Warning
Permanent vision loss.
Sabril Warnings/Precautions
Warnings/Precautions
Be fully familiar with drug’s toxicity before use. Monitor vision, including visual acuity and dilated indirect ophthalmoscopy, and visual fields, at baseline (within 4 weeks) and every 3 months, and for 3–6 months after discontinuing; risk of vision loss increases as dose and cumulative exposure increased. Avoid in patients with, or at high risk of other types of irreversible vision loss. Discontinue if no substantial benefit after treating for 3 months (in adults) or 2–4 weeks (in infants); sooner if obvious treatment failure. Increased risk of suicidal thoughts and behavior; monitor for depression, suicidal ideation, unusual changes in mood/behavior. MRI abnormalities in infants. Renal impairment. Use lowest effective dose for shortest duration. Avoid abrupt cessation. Elderly. Pregnancy. Nursing mothers: not recommended.
REMS
Sabril Pharmacokinetics
Elimination
Renal.
Sabril Interactions
Interactions
May antagonize phenytoin. May potentiate clonazepam. Avoid others that can cause visual or ophthalmic dysfunction. Suppresses ALT/AST activity. May cause false (+) amino acid test.
Sabril Adverse Reactions
Adverse Reactions
CPS: vision loss (may be severe and permanent), other visual changes (blurring, diplopia, asthenopia), fatigue, somnolence, nystagmus, tremor, memory impairment, weight gain, arthralgia, abnormal coordination, confusion, upper respiratory infection, aggression; headache, dizziness, anemia, peripheral neuropathy, edema. IS: somnolence, bronchitis, ear infection, acute otitis media; neurotoxicity (eg, intramyelinic edema).
Sabril Clinical Trials
See Literature
Sabril Note
Notes
To register pregnant patients exposed to vigabatrin call (888) 233-2334. To report ADRs: (800) 455-1141.
Sabril Patient Counseling
See Literature
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