Oxcarbazepine add-on for drug-resistant partial epilepsy.

BACKGROUND

Most people with epilepsy have a good prognosis and their seizures can be well controlled with the use of a single antiepileptic drug, but up to 30 % develop refractory epilepsy, especially those with partial seizures. In this review we summarise the current evidence regarding oxcarbazepine when used as an add-on treatment for drug-resistant partial epilepsy.

OBJECTIVE

To evaluate the effects of oxcarbazepine when used as an add-on treatment for drug-resistant partial epilepsy.

METHODS

We searched the Cochrane Epilepsy Group's trials register, the Cochrane Controlled Trials Register (Cochrane Library Issue 1, 2000), MEDLINE (January 1966 to December 1999) and reference lists of articles. We also contacted Novartis (manufacturers of oxcarbazepine) and experts in the field.

METHODS

Randomized, placebo-controlled, double-blind, add-on trials of oxcarbazepine in patients with drug-resistant partial epilepsy.

METHODS

Two reviewers independently assessed trials for inclusion and extracted the relevant data. The following outcomes were assessed : (a) 50 % or greater reduction in seizure frequency; (b) treatment withdrawal (any reason); (c) side effects. Primary analyses were intention to treat. Summary odds ratios were estimated for each outcome.

RESULTS

Overall Odds Ratio (OR) (95 % Confidence Interval (CIs)) for 50 % or greater reduction in seizure frequency compared to placebo 2.96 (2.20,4.00). Treatment withdrawal OR (95 % CIs) compared to placebo 2.17 (1.59,2.97). Side effects: OR (99 % CIs) compared to placebo, ataxia 2.93(1.72,4.99); dizziness 3.05 (1.99, 4. 67); fatigue 1.80 (1.02, 3.19); nausea 2.88 (1.77, 4.69); somnolence 2.55 (1.84, 3.55); diplopia 4.32 (2.65, 7.04), were significantly associated with oxcarbazepine.

CONCLUSIONS

Oxcarbazepine has efficacy as an add-on treatment in patients with drug-resistant partial epilepsy, both in adults and children. However, trials reviewed were of relatively short duration, and provide no evidence about the long term effects of oxcarbazepine. Results cannot be extrapolated to monotherapy or to patients with other epilepsy types.