Oxcarbazepine, which is chemically similar to carbamazepine, and levetiracetam, a pyrrolidine acetamide chemically unrelated to other antiepileptic drugs, are the sixth and seventh drugs approved by the US Food and Drug Administration in the last five years for oral use in partial seizures.

Anticonvulsants are now widely used for treatment of psychiatric illnesses, particularly bipolar disorder. Lithium is the standard drug for treatment of bipolar disorder, but it can cause severe toxicity, serum concentrations must be monitored, and it is not effective in some patients.

An extended-release formulation of carbamazepine, available since 1997 for treatment of epilepsy, has now been approved under a new name, Equetro, for acute mania and mixed episodes of bipolar disorder. Although the drug was effective in some patients for up to 6 months, it has not been approved for maintenance treatment. Carbamazepine has not been shown to be more effective than lithium or valproate, and it can cause serious adverse effects.

Pregabalin (Lyrica - Pfizer), a structural analog of gamma-aminobutyric acid (GABA) similar to gabapentin (Neurontin - Pfizer, and others), which recently became available generically, has been approved by the FDA for treatment of neuropathic pain associated with postherpetic neuralgia (PHN) and diabetic peripheral neuropathy (DPN), and for adjunctive treatment of partial onset seizures in adults with epilepsy.

The FDA has approved cannabidiol oral solution (Epidiolex – Greenwich Biosciences) for treatment of seizures associated with Dravet syndrome or Lennox-Gastaut syndrome in patients ≥2 years old. Cannabidiol (CBD) is a cannabinoid constituent of the marijuana plant (Cannabis sativa). It is the first natural marijuana product to be approved by the FDA for any indication and the first drug to be approved in the US for treatment of Dravet syndrome. Stiripentol (Diacomit), which is not a marijuana product, was also recently approved by the FDA for treatment of Dravet syndrome in...

The FDA has approved lacosamide (Vimpat - UCB Pharma) for oral or intravenous (IV) use as add-on therapy in adults with partial-onset seizures.

Tiagaine (Gabitril - Abbot), a gamma-aminobutyric acid (GABA) uptake inhibitor, has been approved by the FDA for oral use as an adjunct to other drugs for treatment of partial seizures in patients more than 12 years old. Since most adult patients with resistant epilepsy have partial seizures, new antiepileptic drugs are usually tried first for this indictation.

The FDA has approved vigabatrin (vye gá ba trin; Sabril – Lundbeck) for oral use as add-on therapy for complex partial seizures in adults who are refractory to several antiepileptic drugs and as monotherapy for infantile spasms. Vigabatrin has been available in other countries for many years. Because of its potential for retinal toxicity, it will be available in the US only through a restricted distribution program called SHARE (Support, Help and Resources for Epilepsy). Prescribers and pharmacists distributing the drug must register, and patients must undergo visual field testing.

View the Comparison Table: Some Oral Antiseizure Medications

When used for the appropriate seizure type, antiseizure medications (ASMs) are roughly equivalent in efficacy. In addition to the seizure type, the choice of drug is usually based on factors such as ease of use, spectrum of activity, adverse effects, interactions with other drugs, presence of comorbid conditions, suitability for elderly persons and those with childbearing potential, and cost. Treatment should begin with a single drug, increasing the dosage gradually until seizures are controlled or adverse effects become unacceptable. If seizures persist, expert clinicians generally...