Medicines for preventing epilepsy following traumatic head injury

Background

Traumatic head injury is a frequent event and can injure the brain. This severe injury is often followed by seizures (fits), which may worsen the damage and can lead to chronic epilepsy, a neurologic disorder characterized by frequent recurrent seizures. Antiepileptic drugs are usually given to suppress already diagnosed seizures. Their role in curing the disease and preventing the development of epilepsy in people who are considered at risk for seizures after any brain injury, including head trauma, is not well understood.

Study characteristics

We searched for studies evaluating the effect of early administration of antiepileptic drugs or other potentially neuroprotective agents (which act by protecting the structure or function of nerves) on post-traumatic epilepsy. The primary outcomes of interest were early post-traumatic seizures (within one week of trauma) and late seizures (later than one week post-trauma). We also looked at death, time to late seizure and side effects. The evidence is current to January 2015.

Key results

We found 10 clinical trials involving 2326 people reported in 12 published articles. The evidence available indicated that early treatment with a traditional antiepileptic drug (phenytoin or carbamazepine) may reduce the risk of early post-traumatic seizures. Traditional antiepileptic drugs are no more effective than placebo (a pretend pill) or standard care in reducing late seizures or mortality. Limited data were available for the comparison of an AED with another AED and for the comparison of other potentially neuroprotective agents with placebo. Most studies did not report serious side effects and other side effects.

Quality of the evidence

The overall quality of the evidence varied and findings should be interpreted with caution.

Authors' conclusions: 

This review found low-quality evidence that early treatment with an AED compared with placebo or standard care reduced the risk of early post-traumatic seizures. There was no evidence to support a reduction in the risk of late seizures or mortality. There was insufficient evidence to make any conclusions regarding the effectiveness or safety of other neuroprotective agents compared with placebo or for the comparison of phenytoin, a traditional AED, with another AED.

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Background: 

Head injury is a common event and can cause a spectrum of motor and cognition disabilities. A frequent complication is seizures. Antiepileptic drugs (AED) such as phenytoin are often used in clinical practice with the hopes of preventing post-traumatic epilepsy. Whether immediate medical intervention following head trauma with either AEDs or neuroprotective drugs can alter the process of epileptogenesis and lead to a more favorable outcome is currently unknown. This review attempted to address the effectiveness of these treatment interventions. This review updates and expands on the earlier Cochrane review.

Objectives: 

To compare the efficacy of antiepileptic drugs and neuroprotective agents with placebo, usual care or other pharmacologic agents for the prevention of post-traumatic epilepsy in people diagnosed with any severity of traumatic brain injury.

Search strategy: 

We searched The Cochrane Epilepsy Group's specialized register, CENTRAL, MEDLINE, ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform (ICTRP) in January 2015. We searched EMBASE, Biological Abstracts and National Research Register in September 2014 and SCOPUS in December 2013. The Cochrane Epilepsy Group performed handsearches of relevant journals.

Selection criteria: 

We included randomized controlled trials (RCTs) that include AEDs or neuroprotective agents compared with placebo, another pharmacologic agent or a usual care group. The outcomes measured included a seizure occurring within one week of trauma (early seizure), seizure occurring later than one week post-trauma (late seizure), mortality and any adverse events.

Data collection and analysis: 

Two review authors independently assessed study quality and extracted the data. We calculated risk ratios (RR) and 95% confidence intervals (CI) for each outcome. We used random-effects models in the meta-analyses and performed pre-defined subgroup and sensitivity analyses.

Main results: 

This review included 10 RCTs (reported in 12 articles) consisting of 2326 participants The methodological quality of the studies varied. The type of intervention was separated into three categories; AED versus placebo or standard care, alternative neuroprotective agent versus placebo or standard care and AED versus other AED. Treatment with an AED (phenytoin or carbamazepine) decreased the risk of early seizure compared with placebo or standard care (RR 0.42, 95% CI 0.23 to 0.73; very low quality evidence). There was no evidence of a difference in the risk of late seizure occurrence between AEDs and placebo or standard care (RR 0.91, 95% CI 0.57 to 1.46; very low quality evidence). There was no evidence of a significant difference in all-cause mortality between AEDs and placebo or standard care (RR 1.08 95% CI 0.79 to 1.46,very low quality of evidence). Only one study looked at other potentially neuroprotective agents (magnesium sulfate) compared with placebo. The risk ratios were: late seizure 1.07 (95% CI 0.53 to 2.17) and all-cause mortality 1.20 (95% CI 0.80 to 1.81). The risk ratio for occurrence of early seizure was not estimable.

Two studies looked at comparison of two AEDs (levetiracetam, valproate) with phenytoin used as the main comparator in each study. The risk ratio for all-cause mortality was 0.53 (95% CI 0.30 to 0.94). There was no evidence of treatment benefit of phenytoin compared with another AED for early seizures (RR 0.66, 95% 0.20 to 2.12) or late seizures(RR 0.77, 95% CI 0.46 to 1.30).

Only two studies reported adverse events. The RR of any adverse event with AED compared with placebo was 1.65 (95% CI 0.73 to 3.66; low quality evidence). There were insufficient data on adverse events in the other treatment comparisons.

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