Vigabatrin for oral solution is indicated as adjunctive therapy for adults and pediatric patients 10 years of age and older with refractory complex partial seizures who have inadequately responded to several alternative treatments and for whom the potential benefits outweigh the risk of vision loss. Vigabatrin for oral solution is not indicated as a first line agent for complex partial seizures.
Vigabatrin for oral solution is indicated as monotherapy for pediatric patients with infantile spasms 1 month to 2 years of age for whom the potential benefits outweigh the potential risk of vision loss.
Abnormal magnetic resonance imaging (MRI) signal changes have been observed in some infants treated for infantile spasms with vigabatrin. These changes generally resolved with discontinuation of treatment, and resolved in a few patients despite continued use.
Antiepileptic drugs (AEDs), including vigabatrin, increase the risk of suicidal thoughts and behavior. Monitor patients for the emergence or worsening of depression, suicidal thoughts or behavior, and/or any unusual changes in mood or behavior.
As with all AEDs, discontinue vigabatrin gradually to avoid withdrawal seizures. However, if withdrawal is needed because of a serious adverse event, rapid discontinuation can be considered. Patients and caregivers should be told not to suddenly discontinue vigabatrin therapy.
Vigabatrin can cause anemia, peripheral neuropathy, weight gain, and edema. Vigabatrin can cause somnolence and fatigue. Advise patients not to drive or operate machinery until they know how vigabatrin will affect them.
In clinical studies of 4,079 vigabatrin-treated patients, the most common (≥5%) adverse reactions associated with the use of vigabatrin in combination with other AEDs were headache, somnolence, fatigue, dizziness, convulsion, nasopharyngitis, weight gain, upper respiratory tract infection, visual field defect, depression, tremor, nystagmus, nausea, diarrhea, memory impairment, insomnia, irritability, abnormal coordination, blurred vision, diplopia, vomiting, influenza, pyrexia, and rash.
The adverse reactions most commonly associated with vigabatrin treatment discontinuation in ≥1% of patients were convulsion and depression.
In patients with infantile spasms, the adverse reactions most commonly associated with vigabatrin treatment discontinuation in ≥1% of patients were infections, status epilepticus, developmental coordination disorder, dystonia, hypotonia, hypertonia, weight gain, and insomnia.
Dose adjustment of phenytoin should be considered if clinically indicated, since vigabatrin may cause a moderate reduction in total phenytoin plasma levels. Vigabatrin may moderately increase the Cmax of clonazepam resulting in an increase of clonazepam-associated adverse reactions.
Suppression of alanine transaminase (ALT) and aspartate transaminase (AST) activity by vigabatrin may preclude the use of these markers, especially ALT, to detect early hepatic injury. Vigabatrin may increase the amount of amino acids in the urine, possibly leading to a false positive test for certain rare genetic metabolic diseases (e.g., alpha aminoadipic aciduria).
Do not use vigabatrin during pregnancy unless the potential benefit justifies the potential risk to the fetus. Pregnancy Registry: To provide information regarding the effects of in utero exposure to vigabatrin, physicians should recommend that pregnant patients taking vigabatrin enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry. Patients must call the toll-free number 1-888-233-2334 to enroll. Registry information can be found at http://www.aedpregnancyregistry.org/.
Vigabatrin is excreted in human milk and may cause serious adverse events in nursing infants. Discontinue nursing or discontinue vigabatrin, taking into account the importance of the drug to the mother.
Dose adjustment, including initiating treatment with a lower dose, is necessary in pediatric patients 10 years of age and older and adults with mild (creatinine clearance >50 to 80 mL/min), moderate (creatinine clearance >30 to 50 mL/min) and severe (creatinine clearance >10 to 30 mL/min) renal impairment.