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| content:vigabatrin [2020/02/23 18:04] – [Main disadvantages] icna | content:vigabatrin [2020/02/23 18:14] – [Main disadvantages] icna |
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| * Vigabatrin, may also exaggerate atypical absences (such as those occurring in Lennox–Gastaut syndrome) and myoclonic seizures (such as those occurring in progressive or non-progressive myoclonic epilepsies). | * Vigabatrin, may also exaggerate atypical absences (such as those occurring in Lennox–Gastaut syndrome) and myoclonic seizures (such as those occurring in progressive or non-progressive myoclonic epilepsies). |
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| | ==== Safety of Vigabatrin ==== |
| | * Numerous RCTs failed to detect common and serious visual field defects |
| Numerous RCTs failed to detect common and serious visual field defects | * Vigabatrin was used as and adjunctive medication in the treatment of focal epilepsies from 1989, when it was first licensed in Europe. Concern over neuropathological findings of microvacuolisation of white matter in animals caused trials of vigabatrin to be halted in 1983, but trials were resumed when a lack of evidence (including visualevoked responses) for toxicity in humans was found. |
| Vigabatrin was used as and adjunctive medication in the treatment of focal epilepsies from 1989, when it was first licensed in Europe. Concern over neuropathological findings of microvacuolisation of white matter in animals caused trials of vigabatrin to be halted in 1983, but trials were resumed when a lack of evidence (including visualevoked responses) for toxicity in humans was found. | * Numerous RCTs (mostly of class I and II in the ratings of ‘therapeutic articles’)[(:cite:2006001>{{pubmed>2006001}})][(:cite:9203252>{{pubmed>9203252}})][(:cite:2667602>{{pubmed>2667602}})][(:cite:8952010>{{pubmed>8952010}})][(:cite:8439699>{{pubmed>8439699}})][(:cite:8559421>{{pubmed>8559421}})][(:cite:9022432>{{pubmed>9022432}})][(:cite:10406359>{{pubmed>10406359}})] |
| | * All these studies[(:cite:2006001>{{pubmed>2006001}})][(:cite:9203252>{{pubmed>9203252}})][(:cite:2667602>{{pubmed>2667602}})][(:cite:8952010>{{pubmed>8952010}})][(:cite:8439699>{{pubmed>8439699}})][(:cite:8559421>{{pubmed>8559421}})][(:cite:9022432>{{pubmed>9022432}})][(:cite:10406359>{{pubmed>10406359}})] concluded that vigabatrin was a ‘relatively safe drug with a relatively benign adverse-effect profile’. They all failed to identify vigabatrin-associated irreversible visual field defects. |
| Numerous RCTs (mostly of class I and II in the ratings of ‘therapeutic articles’)3-10 were all consistent in their conclusion that vigabatrin was a ‘relatively safe drug with a relatively benign adverse-effect profile’. They all failed to identify vigabatrin-associated irreversible visual field defects. It was astute clinicians who first reported these serious ADRs,9 but even after this report had been published, a class I RCT found vigabatrin to be ‘less effective but better tolerated than carbamazepine’.10 Results of proper testing for visual field defects are not given; that the patients did not have abnormalities on visual confrontation testing is not reassuring. When such ADRs come to light, good clinical practice mandates that patients are informed and offered the appropriate testing. Visual field testing performed by a protocol amendment post hoc (after termination of another RCT) showed abnormalities in 10% of vigabatrin-treated patients.11 | * It was astute clinicians who first reported these serious ADRs[(:cite:9022432>{{pubmed>9022432}})], but even after this report had been published, a class I RCT found vigabatrin to be ‘less effective but better tolerated than carbamazepine’[(:cite:10406359>{{pubmed>10406359}})].Results of proper testing for visual field defects are not given; that the patients did not have abnormalities on visual confrontation testing is not reassuring. When such ADRs come to light, good clinical practice mandates that patients are informed and offered the appropriate testing. Visual field testing performed by a protocol amendment post hoc (after termination of another RCT) showed abnormalities in 10% of vigabatrin-treated patients[(:cite:11051124>{{pubmed>11051124}})]. |
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| Authorities failed to warn of the pro-absence effects of vigabatrin | |
| That vigabatrin is a pro-absence AED should be evident by its action on GABAB receptors. No such warning was given to practising physicians,13 who only discovered this effect when patients with IGEs experienced significant deterioration and absence status epilepticus.4 | |
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| ==== References ==== | ==== References ==== |
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| ~~REFNOTES~~ | ~~REFNOTES~~ |
