Antiseizure drugs may not need to be taken indefinitely. Children who are seizure free for periods longer than 2–4 years while on antiseizure medications will remain so when medications are withdrawn in 70% of cases. The risk of recurrence depends on the seizure syndrome. Resolution of seizures is common for generalized absence epilepsy but not for juvenile myoclonic epilepsy. Other risk factors for recurrence are an abnormal EEG, the presence of neurologic deficits, or when seizure control had been difficult to achieve. There is little information on antiseizure drug withdrawal in seizure-free adults. Withdrawal is believed to be more likely to be successful in patients with generalized epilepsies who exhibit a single seizure type, whereas longer duration of epilepsy, an abnormal neurologic examination, an abnormal EEG, and certain epilepsy syndromes, including juvenile myoclonic epilepsy, are associated with increased risk of recurrence. Drugs are generally withdrawn slowly over a 1to 3-month period or longer. Abrupt cessation may be associated with return of seizures and even a risk of status epilepticus. Some drugs are more easily withdrawn than others. Physical dependence occurs with barbiturates and benzodiazepines, and there is a well-recognized risk of rebound seizures with abrupt withdrawal.
Several potential new antiseizure drugs are in late clinical development; these are Staccato (thermal aerosol inhaled) alprazolam, for acute repetitive seizures; intranasal midazolam, for acute repetitive seizures; allopregnanolone, for status epilepticus; ganaxolone, for status epilepticus and rare epilepsy syndromes; cannabidiol, for epileptic encephalopathies and focal seizures; cannabidivarin, for focal seizures; cenobamate (YKP3089), for focal seizures; fenfluramine, for Dravet’s syndrome; and stiripentol, for Dravet’s syndrome. Other drugs are in earlier stages of development; current information can be found on the Epilepsy Foundation website at http://www.epilepsy.com/etp/pipeline_new_therapies.
• Oxcarbazepine: