Primary Generalized Epilepsies.
For pure childhood absence epilepsy (CAE), ethosuximide (ESM) remains the drug of first choice. Although valproic acid (VPA) is of equal efficacy, it is more toxic, and is reserved for those patients with accompanying convulsions. Lamotrigine (LTG) is effective as both add-on and monotherapy for CAE. If any of these three drugs fails, one of the other two can be used as monotherapy. Rarely, when ESM, VPA, or LTG does not effectively control CAE, phenytoin (PHT), primidone (PRM), and phenobarbital (PB) may be partially effective, although carbamazepine (CBZ) may worsen absence seizures. Experience is limited with the newer AEDs. Tiagabine (TGB) may induce absence status epilepticus in PGE. Oxcarbazepine (OXC) and vigabatrin (VGB) may worsen absence seizures. Felbamate (FBM) is probably effective, but is potentially fatal. Lifelong therapy is not anticipated. For juvenile absence epilepsy (JAE), VPA is the drug of first choice. LTG is also of proven efficacy. The risks of VPA-induced teratogenicity (possibly lessened by the concurrent use of folic acid) and weight gain are potentially unacceptable in young women of childbearing age. Not enough data exists on the safety of LTG in pregnancy. A combination of VPA and LTG can be used if either drug alone is unsuccessful. For juvenile myoclonic epilepsy (JME), VPA is the traditional drug of first choice in most patients. As in JAE, side effects may make VPA an unacceptable choice in many patients, especially young women. In clinical practice, TPM is being increasingly used as monotherapy for JME. Many patients appreciate the accompanying weight loss seen with TPM, but it has potentially troubling side effects, has not been well studied as monotherapy for JME, and its safety in pregnancy has yet to be confirmed. PHT and CBZ may worsen myoclonus when used alone, but they may have a role as add-on treatment to VPA, LTG, or TPM, especially when generalized tonic-clonic seizures (GTCSs) are not controlled. PB and PRM may also be useful as add-on treatment, but often have unacceptable side effects. Clonazepam may be useful as adjunctive treatment for resistant myoclonic jerks. OXC and VGB both worsen myoclonic seizures. GBP is not useful in JME and can make seizures worse. The efficacy of FBM and TGB in JME is largely unknown. Lifelong AED therapy is necessary. In epilepsy with generalized tonic-clonic seizure (GTCS) on awakening (EGA), VPA is the drug of choice, especially if other seizure types (absence and myoclonic) are present. If only GTCSs are present, then PB, PHT, and CBZ may be as effective as VPA; however, the use of PHT and CBZ may "unearth" other seizure types (absence and myoclonic) in those patients with EGA, although PB is poorly tolerated. As for JME, LTG, and TPM may both be effective monotherapy for EGA, although the use of other AEDs in EGA has not been well studied. Lifelong AED treatment is necessary.
Murphy
K
Department of Clinical Neurological Sciences, Royal College of Surgeons in Ireland and Beaumont Hospital, PO Box 1297, Beaumont Road, Dublin 9, Ireland.
Delanty
N