Vigabatrin for tuberous sclerosis complex
ABSTRACT Vigabatrin (VGB) was found to be an effective anti-epileptic drug to reduce infantile spasms in about 50% of patients and it has been found most effective in infantile spasms due to tuberous sclerosis (TSC) in which up to 95% of infants had complete cessation of their spasms. VGB was synthesized to enhance inhibitory gamma-aminobutyric acidergic (GABAergic) transmission by elevating GABA levels via irreversible inhibition of GABA transaminase. The mechanism underlying the particular efficacy of VGB in TSC is still unknown. However, its efficacy suggests that epileptogenesis in TSC may be related to an impairment of GABAergic transmission. VGB should be considered as the first line monotheraphy for the treatment of infantile spasms in infants with confirmed diagnosis of TSC. The efficacy of VGB treatment can be assessed in less than 10 days, but usually a few days treatment with a dose of about 100 mg/kg/day stops infantile spasms. The cessation of the spasms is associated with a marked improvement of behaviour and mental development. Unfortunately, it has become clear that the use of VGB is associated with a late appearance of visual-field defects in up to 50% of patients. Currently the minimum duration and doses of VGB treatment that can produce side effects are unknown. The feasibility of using short treatment periods (2-3 months) should be investigated.
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- "However, in contrast to most other antiseizure medications, VGB is particularly effective for seizures in TSC, especially infantile spasms, a typically devastating type of childhood seizure. VGB has been reported to eliminate spasms in about 95% of cases, which is much higher than all other treatments for spasms due to TSC or any other cause , . In fact, this special relationship between VGB and TSC is one of the few documented examples of a medication having individualized efficacy for a specific epilepsy syndrome or cause of epilepsy. "
ABSTRACT: Epilepsy is a common neurological disorder and cause of significant morbidity and mortality. Although antiseizure medication is the first-line treatment for epilepsy, currently available medications are ineffective in a significant percentage of patients and have not clearly been demonstrated to have disease-specific effects for epilepsy. While seizures are usually intractable to medication in tuberous sclerosis complex (TSC), a common genetic cause of epilepsy, vigabatrin appears to have unique efficacy for epilepsy in TSC. While vigabatrin increases gamma-aminobutyric acid (GABA) levels, the precise mechanism of action of vigabatrin in TSC is not known. In this study, we investigated the effects of vigabatrin on epilepsy in a knock-out mouse model of TSC and tested the novel hypothesis that vigabatrin inhibits the mammalian target of rapamycin (mTOR) pathway, a key signaling pathway that is dysregulated in TSC. We found that vigabatrin caused a modest increase in brain GABA levels and inhibited seizures in the mouse model of TSC. Furthermore, vigabatrin partially inhibited mTOR pathway activity and glial proliferation in the knock-out mice in vivo, as well as reduced mTOR pathway activation in cultured astrocytes from both knock-out and control mice. This study identifies a potential novel mechanism of action of an antiseizure medication involving the mTOR pathway, which may account for the unique efficacy of this drug for a genetic epilepsy.PLoS ONE 02/2013; 8(2):e57445. DOI:10.1371/journal.pone.0057445 · 3.23 Impact Factor
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- "Vigabatrin is used with advantage in treatment of IS especially in cases associated to tuberous sclerosis complex [108-110]. Doses are usually around 100 mg/Kg/day with a gradual increase but maintained at the lowest effective dosage. Superior doses seem not to be of benefit. "
ABSTRACT: This epileptic disorder has become a classic topic for neuropediatricians and the interest is documented by the large number of publications on this subject. The relative frequency among the epileptic syndromes is an another reason why not only neuropediatricians but also general pediatricians must be fully informed about diagnostic, clinical, imaging and genetic aspects. Early diagnosis is of paramount importance in order to obtain even complete results in patients with so called idiopathic situations. A number of problems are still to be solved. There is no agreement on the type and the schedule of treatment. A common denominator about this problem is not jet available even if some advances in this regard have been accomplished. Of paramount importance is an accurate clinical and laboratory examination as a prerequisite regarding prognosis and results of therapy in every single case. However, even if more than 170 years have elapsed since the first communication of dr. West on the peculiar syndrome that his child was suffering of, the interest of scientists on this subject has now been enriched and rewarded.Italian Journal of Pediatrics 02/2010; 36(1):15. DOI:10.1186/1824-7288-36-15 · 1.52 Impact Factor
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- "Vigabatrin (VGB) is an antiepileptic drug with proven efficacy in the treatment of infantile spasms (IS) and partial seizures (PS) in children. It is regarded by many as the first choice in the treatment of IS in tuberous sclerosis complex (TSC) (Curatolo et al., 2001; Riikonen, 2005; Wheless et al., 2007), and can result in complete IS control in 95% of cases (Hancock & Osborne, 1999). In IS with etiologies other than TSC, VGB, and adrenocorticotropic hormone (ACTH), the other commonly used agents for IS, have comparable efficacy (54% IS cessation) (Riikonen, 2004). "
ABSTRACT: To review the efficacy, cognitive outcome and safety profile in children treated with vigabatrin (VGB) for infantile spasms (IS) and partial epilepsies related to tuberous sclerosis complex (TSC) and other etiologies. Retrospective review of children followed in the Pediatric Epilepsy Program of Massachusetts General Hospital for Children between May 2001 and March 2006 who were treated with VGB. Eighty-four children were treated with VGB, 68 of them were treated for IS, and 59 were treated for partial seizures (PS). Etiology (TSC or other) was the only predictive factor for IS control with VGB (p < 0.0003). IS control was achieved in 73% of children with TSC and 27% of children with other etiologies (combined 56%). Partial onset seizures were controlled in 34% of all children, (17% seizure free,17%reduction in seizure frequency >50%) and no predictive factor was found. Shorter time from seizure onset to VGB treatment (p < 0.027) and longer total time on VGB (p < 0.045) was associated with better IQ-developmental quotient (DQ) outcome in children treated for IS, but not with IS control. Adverse events were seen in 13%. Electroretinogram and/or behavioral visual field (VF) testing was done in 52%. VGB was discontinued in one case due to abnormal electroretinogram (ERG) findings. We confirm the efficacy of VGB in the treatment of IS and PS in an American population. VGB may improve cognitive outcome in the absence of complete IS control, but this finding is of uncertain clinical significance. VGB was well tolerated, and ophthalmologic side effects were uncommon.Epilepsia 07/2008; 49(7):1186-91. DOI:10.1111/j.1528-1167.2008.01589.x · 4.57 Impact Factor