Refractory idiopathic absence status epilepticus: A probable paradoxical effect of phenytoin and carbamazepine.
OBJECTIVE
To compare the frequency of seizures and status epilepticus and their response to first-line drugs in patients with idiopathic generalized epilepsies receiving carbamazepine or phenytoin to those receiving other drugs or no treatment.


METHODS
We performed a retrospective chart review of all cases of idiopathic generalized epilepsies treated by the authors between 1985 and 1994. We compared seizure frequency and mean intravenous benzodiazepine dose required to control absence status epilepticus, intraindividually in subjects on carbamazepine or phenytoin before and after discontinuation of these compounds, and interindividually to subjects without treatment or receiving other drugs.


RESULTS
Bouts of absence or tonic-clonic status epilepticus and seizures in subjects treated with phenytoin or carbamazepine at therapeutic concentrations were considerably more frequent and proved intractable to treatment with valproic acid or benzodiazepines, compared with a cohort of subjects also with idiopathic generalized epilepsies, but naive to, or receiving subtherapeutic or therapeutic doses of other agents.


CONCLUSIONS
Our observations strongly suggest that therapeutic concentrations of phenytoin and carbamazepine exacerbate idiopathic generalized epilepsies. Subjects in whom absence is one of the seizure types seem at a particularly high risk for responding paradoxically. These findings underscore the value of accurate classification of seizures and particularly the syndromic approach to diagnosis and point to the potential for iatrogenic complications with indiscriminate use of antiseizure drugs.
Osorio
I
I
Comprehensive Epilepsy Center, University of Kansas Medical Center, Kansas City, Kansas 66160, USA. iosorio@kumc.edu
Reed
R C
RC
Peltzer
J N
JN
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000927:Anticonvulsants / Q000009:adverse effects* / Q000627:therapeutic use; D002220:Carbamazepine / Q000009:adverse effects* / Q000627:therapeutic use; D002648:Child; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D004359:Drug Therapy, Combination; D004569:Electroencephalography / Q000187:drug effects / Q000706:statistics & numerical data; D004832:Epilepsy, Absence / Q000139:chemically induced* / Q000188:drug therapy; D004829:Epilepsy, Generalized / Q000188:drug therapy*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010672:Phenytoin / Q000009:adverse effects* / Q000627:therapeutic use; D013226:Status Epilepticus / Q000139:chemically induced* / Q000188:drug therapy; D016896:Treatment Outcome
D000927:Anticonvulsants; D002220:Carbamazepine; D010672:Phenytoin