REVIEW QUESTION

What is the effect on seizure recurrence, seizure remission, mortality, and adverse effects of starting antiepileptic drug treatment immediately following a first seizure?

TYPE OF REVIEW

A systematic review of six studies.

RELEVANCE FOR NURSING

An initial unprovoked epileptic seizure has an estimated incidence of 33 to 98 per 100,000 people per year. The two- and three-year recurrence rates of a first unprovoked seizure have been estimated at between 23% and 71%. The decision to start early antiepileptic drug treatment after a single unprovoked seizure remains controversial. When considering initial drug treatment for a first unprovoked seizure, it is important to assess the relative risk of seizure recurrence and compare that with the disadvantages of treatment with antiepileptic drugs; information on the reduction in risk of future seizures, seizure remission, and the risk of adverse effects should also be taken into consideration.

CHARACTERISTICS OF THE EVIDENCE

In this systematic review, the authors assessed the outcomes associated with antiepileptic drug treatment given immediately after a first unprovoked epileptic seizure compared with placebo, deferred treatment, or no treatment. Six randomized controlled trials (RCT) or quasi-RCTs (nine reports) of adults, children, or both who had a first unprovoked seizure were selected for inclusion. The antiepileptic drugs included in the studies were carbamazepine, lamotrigine, phenobarbital, phenytoin, and valproate. For the two largest studies, data were available for individual participant meta-analysis.

Compared with controls, participants randomized to immediate treatment had a significantly lower probability of seizure recurrence at five years and a higher probability of an immediate five-year remission. Antiepileptic drugs did not affect overall mortality after a first seizure. Compared with deferred treatment, treatment of a first seizure was associated with a significantly higher risk of adverse effects.

BEST PRACTICE RECOMMENDATIONS

These findings provide strong evidence that use of immediate antiepileptic drug treatment for a first unprovoked seizure can decrease the risk of seizure recurrence, and increase the probability of seizure remission, compared with placebo, deferred treatment, or no treatment. However, treatment seems to carry a higher risk of adverse effects.

Generally, there is agreement that antiepileptic drug treatment should be postponed until a second seizure has occurred. Thus, decisions about access to treatment should be made following discussions between the health care providers and the patient and family that consider patient risk and the impact of seizure recurrence. Adverse effects associated with antiepileptic drug treatment following a first unprovoked seizure should be of particular concern to children, pregnant women, and the elderly; therefore, the decision to start antiepileptic drug treatment should be individualized and based on patient preference and on clinical, legal, and sociocultural factors.

RESEARCH RECOMMENDATIONS

According to the findings of this systematic review, antiepileptic drug treatment is not beneficial to the majority of patients with a first unprovoked seizure. Although existing antiepileptic drugs may decrease the risk of a seizure, they only reduce the risk of seizure recurrence in the short term. Further studies are required to support this reliable prediction of outcome for such patients.

REFERENCE