Anticonvulsants

Anticonvulsant drugs

Drugs used to prevent or reduce the severity and frequency of seizures (convulsions). Seizures occur when the electrical activity in the brain that controls the movement of the limbs becomes paroxysmal and chaotic.

The most common form of seizures is epilepsy . Since not all seizures involve convulsions, and not all types of convulsion are epileptic seizures, the term antiepileptic is often preferred to describe medication for treating epilepsy. Most people with epilepsy need to take anticonvulsants on a regular basis until they have been free of seizures for two years. The type of drug used will depend on the type of epilepsy, although a patient's age and response to treatment may also affect the choice of drug.

Tonic-clonic (or major) seizures (formerly called 'grand mal'), in which a period of unconsciousness is followed by convulsions, usually last only a few minutes; prolonged attacks, in which repeated seizures occur with no intervening recovery of consciousness, are called status epilepticus.

The main drugs used to treat major seizures are carbamazepine, phenytoin, and sodium valproate; phenobarbitone (phenobarbital) and primidone may also be used but are more sedating. Drugs used in the treatment of status epilepticus include diazepam, phenytoin, and paraldehyde.

Absence seizures (formerly called 'petit mal'), which usually affect children and consist of a momentary loss of consciousness during which posture and balance are maintained, are treated with ethosuximide, sodium valproate, and (less commonly) clonazepam.

Partial seizures, in which the nature of the seizure depends on the part of the brain that is affected, are most commonly treated with phenytoin, sodium valproate, and carbamazepine; phenobarbitone and primidone may also be effective.

Lamotrigine, vigabatrin, gabapentin, tiagabine, topiramate, and piracetam are newer anticonvulsants that may be used as adjuncts to (or replacements for) older medicines.