Monotherapy has been promoted as the ideal in epilepsy treatment because of reduced side effects, absence of drug interactions, better compliance, lower cost and, in many cases, improved seizure control compared to polytherapy. The question of monotherapy vs. polytherapy has assumed increasing importance with the availability of multiple new antiepileptic drugs (AEDs), initially tested as add-on agents. The new drugs clobazam, lamotrigine, vigabatrin, gabapentin and topiramate, have also been shown to be effective as monotherapy. These data bring up the possibility of using them as first-line agents. However, a high percentage of patients with resistant epilepsy are treated with polytherapy, which probably benefits only a minority of them. The availability of multiple drugs with different mechanisms of action favours the possibility of "rational polytherapy", taking advantage of possible synergism, a yet unproven concept. This article reviews the theoretical advantages of monotherapy and monotherapy with traditional and newer AEDs.

The long-standing debate between proponents of monotherapy and those of polytherapy for treatment of epilepsy has been rekindled by the recent development of several new antiepileptic drugs. The likelihood of improved seizure control on polytherapy must be weighed against the risk of increased side effects, complex drug interactions and cost. Providing maximal seizure control while avoiding overtreatment is a challenge which requires an ongoing critical evaluation of each patient's management. This review provides a framework for decision-making by considering issues affecting the choice between monotherapy and polytherapy in five clinical situations: 1) newly diagnosed epilepsy; 2) seizures on monotherapy; 3) seizures controlled on polytherapy; 4) not controlled on polytherapy; 5) change in medical condition.

Data from clinical trials with lamotrigine indicate that the risk of serious rash in pediatric patients is higher than in adults. The incidence of rash associated with hospitalization among adults treated with lamotrigine is 0.3% and among pediatric patients 1.0%. The incidence of cases reported as possible Stevens-Johnson syndrome is 0.1% for adult patients and 0.5% for pediatric patients. These rates reflect lamotrigine dosing and concomitant AEDs used in these trials, both of which are risk factors for rash. Since many of the trials were conducted prior to the establishment of the current dosing recommendations, the incidence of serious rash in clinical trials does not necessarily reflect the incidence to be expected with use of current dosing recommendations. The higher incidence of serious rash in pediatric patients may at least partially be accounted for by the differential effects of the risk factors of dosing and concomitant use of valproic acid in these patients.

Improving health-related quality of life in epileptic patients, rather than simply reducing seizures, has become the principal goal in epilepsy management. Reducing seizure frequency is one of the main factors contributing to improved quality of life. Evidence for and risk of the following potential adverse effects of seizures is reviewed: brain damage from seizures, sudden unexpected death, status epilepticus, kindling, falls or injury and psychosocial consequences. Although the evidence for seizure frequency influencing some of these factors is not clear-cut, as a whole, they offer a strong impetus toward an aggressive approach to controlling recurrent seizures in most cases.

Epilepsy encompasses medical, psychological, social and demographic factors which are best studied in large populations. The Canadian Epilepsy Database and Registry (CEDAR) is a comprehensive English language, multicentre epilepsy database which has been developed to study the impact of these and other factors on epilepsy in Canada. In addition, it can be used locally in the clinic for office record keeping, automated printout of a referral letter or graphing seizures and other data over time. The data in CEDAR are similar to what is found in the patient's chart. There are 20 participating centres across Canada which have entered data on over 8000 adult and pediatric epilepsy patients. The information in CEDAR will be available for research purposes to centres entering data as well as to academic researchers, the pharmaceutical industry and government agencies.