Principles of treatment of epilepsy

Abstract

Epilepsy is a common chronic neurological condition with a prevalence of 4-8 per thousand (Hauser, 1990). The present classification of epilepsy is based on two pillars: the aetiology, which distinguishes symptomatic epilepsies from those that are idiopathic and cryptogenic, and the localisation of the disorder in the brain, separating the generalised seizures form epilepsies with partial of focal onset. The majority of the patients with epilepsy will go into remission, and two-thirds will remain so, two years after drug withdrawal. The impact of epilepsy on individual patients varies. Employment, driving and learning may constitute major problems. There is a small, but definite increase in mortality in patients suffering from epilepsy. Treatment of epilepsy usually involves long term medical treatment, and the ultimate aim will be no seizures and no drugs. Before starting treatment, the diagnosis of epilepsy should be secure. Initiation of antiepileptic drug therapy needs a full and adequate discussion with the patient, and the choice of the minimum effective dose of an appropriate monotherapy. Nonpharmacological treatments may demand consideration at a relatively early stage, if pharmacological treatment is ineffective. In choosing between different drugs, judgements about the efficacy of the drug for an individual patient and its tolerability, contribute to the overall effectiveness of an antiepileptic drug. There is good evidence from many studies that the chief factor determining relative effectiveness is likely to be the spectrum and incidence of adverse effects of antiepileptic drugs. Some 20% of patients developing epilepsy have a chronic disorder, uncontrolled by drugs. In patients receiving, and complying with, optimal doses of a single antiepileptic drug, the addition of further agents is likely to result in a significant improvement in seizure control in only approximately 10% of patients, but inevitably it increases the risks of dose-related, idiosyncratic, and chronic toxicity due to both pharmacokinetic and pharmacodynamic drug interactions. For this group of patients an appropriate aim may not be complete remission of seizures but a compromise of reduced seizure frequency with less severe seizures, to be achieved with one, or at most two, drugs. The management of these patients with unremitting seizures constitute a treatment challenge for epileptologists.