[Info] AEDs aggravating seizures / triggering new seizures

[Dutch mom]

http://onlinelibrary.wiley.com/doi/1...268.x/abstract

Carabamazepine, in particular, has been reported to precipitate or exacerbate a variety of seizures, most notably absence, atonic, or myoclonic seizures in patients with generalized epilepsies characterized by bursts of diffuse and bilaterally synchronous spike-and-wave EEG activity. Phenytoin and vigabatrin also have been implicated in worsening of seizures, particularly generalized seizures, whereas gabapentin has been associated repeatedly with precipitation of myoclonic jerks. Benzodiazepines occasionally have been reported to precipitate tonic seizures, especially when given intravenously to control other seizure types in patients with Lennox-Gastaut syndrome. Seizure deterioration has been reported also with other drugs; though in most cases evidence is still insufficient for meaningful conclusions to be drawn.

http://onlinelibrary.wiley.com/doi/1...118.x/abstract

Summary: Antiepileptic drugs (anti-epileptic drugs) may aggravate preexisting seizures and trigger new seizure types. However, the extent and mechanisms of this problem are unclear, for several reasons. anti-epileptic drug trials are not designed to detect worsening of seizures, severe childhood epilepsies may fluctuate in severity, and worsening of seizures may be over-hastily ascribed to the introduction of a new anti-epileptic drug. Moreover, the seizure and the epilepsy type may have been incorrectly diagnosed. The problem is identification of true aggravation of epilepsy in the absence of overdosage or toxicity. This is a common and clinically important problem that concerns both established and newer anti-epileptic drugs, but the biologic mechanisms involved are unknown. An increase in seizure frequency due to overdosage has been reported with phenytoin but is rare with other anti-epileptic drugs. Paradoxical reaction has been reported with carbamazepine (CBZ), benzodiazepines, and vigabatrin (VGB). Exacerbation of seizures may also occur during anti-epileptic drug-induced encephalopathy or hepatopathy. An inappropriate choice of the anti-epileptic drug (i.e., a purely pharmacodynamic mechanism) can induce worsening when CBZ or VGB is used in absence and myoclonic seizures. Further research should determine whether seizure exacerbation is associated with the type of epilepsy or with the type of EEG abnormality. Recent evidence indicates that lamotrigine is inappropriate in severe myoclonic epilepsy. Some childhood epileptic encephalopathies have been affected by certain seizure-worsening mechanisms. Whether this is due to a predisposition in specific syndromes or to an increased risk for adverse effects in patients undergoing multiple anti-epileptic drug manipulations is unclear. Furthermore, some syndromes are not the sum of accompanying seizure types but have unique neurobiology.