Carbamazepine versus phenytoin monotherapy for epilepsy

Tudur Smith C, Marson AG, Clough HE, Williamson PR

Published Online:

March 17, 2010

There is no evidence to suggest any difference between the drugs carbamazepine and phenytoin for the seizure types studied.

Epilepsy is a disorder where recurrent seizures are caused by abnormal electrical discharges from the brain. Carbamazepine and phenytoin are considered first line treatments in many countries both for partial onset seizures and generalized tonic-clonic seizures. The review of trials found no difference between carbamazepine and phenytoin for the control of the seizure types studied.

Abstract (click to read)

Background:

This is an updated version of the original Cochrane review published in Issue 2, 2002.

Worldwide, carbamazepine and phenytoin are commonly used antiepileptic drugs. This review summarizes evidence from randomized controlled trials in which these two drugs have been compared.

Objectives:

To review the best evidence comparing carbamazepine and phenytoin when used as monotherapy in people with partial onset seizures, or generalized onset tonic-clonic seizures with or without other generalized seizure types.

Search strategy:

We searched the Cochrane Epilepsy Group's Specialized Register (November 2009), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 4, 2009), and MEDLINE (1950 to week 2, November 2009). No language restrictions were imposed. We also contacted pharmaceutical companies, experts in the field, and trial investigators.

Selection criteria:

Randomized controlled trials in children or adults with partial onset seizures or generalized onset tonic-clonic seizures. Trials must have included a comparison of carbamazepine monotherapy with phenytoin monotherapy.

Data collection and analysis:

This was an individual patient data review. Outcomes were time to (a) withdrawal of allocated treatment; (b) 12 month remission; (c) six month remission and (d) first seizure post randomization. Data were analysed using a stratified logrank analysis with results expressed as hazard ratios (HR) and 95% confidence intervals (95% CI), where a HR greater than one indicates an event is more likely on phenytoin.

Main results:

Individual patient data are available for 551 participants from three trials, representing 61% of the participants recruited into the nine trials that met our inclusion criteria. By convention, for the outcomes time to six and 12 month remission HR greater than one indicates a clinical advantage for phenytoin, whilst for time to withdrawal and first seizure HR greater than one indicates a clinical advantage for carbamazepine. Results (HRs) were: (i) time to withdrawal of allocated treatment 0.97 (95% CI 0.74 to 1.28); (ii) time to 12 month remission 1.00 (95% CI 0.78 to 1.29); (iii) time to six month remission 1.10 (95% CI 0.87 to 1.39) and (iv) time to first seizure 0.91 (95% CI 0.74 to 1.12). The results suggest no overall difference between carbamazepine and phenytoin for these outcomes.

Authors' conclusions:

We have not found evidence that a significant difference exists between carbamazepine and phenytoin for the outcomes examined in this review. Confidence intervals are wide and the possibility of important differences existing has not been excluded.

This record should be cited as:

Tudur Smith C, Marson AG, Clough HE, Williamson PR. Carbamazepine versus phenytoin monotherapy for epilepsy. Cochrane Database of Systematic Reviews 2002, Issue 2. Art. No.: CD001911. DOI: 10.1002/14651858.CD001911

Assessed as up to date:

January 19, 2010

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Primary Review Group:

Epilepsy Group

Health topics:

Neurology > Epilepsy > Drugs for broad populations

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Carbamazepine versus phenytoin monotherapy for epilepsy

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