• Management (adjunctive) of refractory complex partial seizures in patients who have responded inadequately to several alternative treatments (and where potential benefit outweighs risk of vision loss); not a first-line treatment.
• Management of infantile spasms (IS).

Contraindicated in:

• History or high risk of other types of irreversible vision loss unless benefits of treatment clearly outweigh risks
• OB: Use only if the potential benefit justifies the potential risk to the fetus (may cause fetal harm)
• Lactation: Enters breast milk; breast feeding should be avoided.

Use Cautiously in:

• Renal impairment (dose modification recommended for CCr <50 mL/min)
• History of suicidal ideation
• Geri: Consider age-related ↓ in renal function adjust dose accordingly (↑ risk of sedation/confusion)
• Pedi: Abnormal MRI signal changes have been seen in infants.

CNS: SUICIDAL THOUGHTS, confusional state, memory impairment, drowsiness, fatigue.

CV: edema.

Derm: STEVENS-JOHNSON SYNDROME, TOXIC EPIDERMAL NECROLYSIS.

EENT: blurred vision, nystagmus, vision loss, tunnel vision.

Hemat: anemia.

Metab: weight gain.

MS: arthralgia.

Neuro: abnormal coordination, tremor, peripheral neuropathy.

Drug-Drug:

• Should not be used concurrently with other drugs having adverse ocular effects; ↑ risk of additive toxicity.
• May ↓ phenytoin levels and effectiveness.

(Generic available)

• Tablets: 500 mg;
• Powder packets for oral solution: 500 mg/pkt;

Refractory Complex Partial Seizures

• PO (Adults and Children >16 yr): 500 mg twice daily initially, may be ↑ in 500 mg increments every 7 days depending on response up to 1500 mg twice daily.
• PO (Children 10–16 yr and >60 kg): 500 mg twice daily initially, may be ↑ in 500 mg increments every 7 days depending on response up to 1500 mg twice daily.
• PO (Children 10–16 yr and 25–60 kg): 250 mg twice daily initially, may be ↑ every 7 days depending on response up to 1000 mg twice daily.

Infantile Spasms

• PO (Children 1 mo–2 yr): 25 mg/kg twice daily initially, may be ↑ by 25-50 mg/kg/day increments every 3 days up to a maximum of 150 mg/kg/day (75 mg/kg twice daily); dosage adjustments are necessary for renal impairment.

Sabril

• Acts an irreversible inhibitor of -aminobutyric acid transaminase (GABA-T), the enzyme responsible for the metabolism of the inhibitory neurotransmitter GABA. This action results in increased levels of GABA in the central nervous system.

• Decreased incidence and severity of refractory complex partial seizures.

Therapeutic Classification: anticonvulsants

Absorption: Completely absorbed following oral administration.

Distribution: Enters breast milk, remainder of distribution unknown.

Protein Binding: None.

Metabolism/Excretion: Minimal metabolism, mostly eliminated unchanged in urine.

Half-life: 7.5 hr.

(anticonvulsant effect)

†blood level.

†clinical benefit should be seen in 2–4 wk for IS or within 3 mo for complex partial seizures.

• Enroll patient in SHARE Program. Instruct patient to take vigabatrin around the clock, as directed. Discuss with health care professional what to do if a dose is missed. Medication should be gradually discontinued to prevent seizures. Advise patient to read the Medication Guide before starting therapy and with each Rx refill in case of changes.
• Educate patient on risks of vigabatrin. Inform patient of the risk of permanent vision loss, particularly loss of peripheral vision, and that vision loss may not be detected before it is severe and is irreversible. Emphasize the importance of monitoring vision every 3 mo. Advise patient to notify health care professional immediately if changes in vision (not seeing as well as before starting therapy, tripping, bumping into things, more clumsy than usual, surprised by people or things coming in front of you that seem to come out of nowhere) or changes in infant's vision are suspected.
• May cause drowsiness, ataxia, fatigue and confusion. Caution patient to avoid driving or other activities requiring alertness until response to medication is known. Tell patient not to resume driving until physician gives clearance based on control of seizure disorder.
• Inform patients and families of risk of suicidal thoughts and behavior and advise that behavioral changes, emergency or worsening signs and symptoms of depression, unusual changes in mood, or emergence of suicidal thoughts, behavior, or thoughts of self-harm or rash should be reported to health care professional immediately.
• Advise patient to notify health care professional if an increase in seizures, weight gain, or edema occurs or if sleepiness, ear infection, or irritability occurs in an infant.
• Instruct patient to notify health care professional of all Rx or OTC medications, vitamins, or herbal products being taken, to consult health care professional before taking any new medications and to avoid taking alcohol or other CNS depressants concurrently with vigabatrin
• Advise female patients to notify health care professional if pregnancy is planned or suspected or if breast feeding. Encourage pregnant patients to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling 1-888-233-2334; information is available at .

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