Review of new antiepileptic drugs as initial therapy

Pharmacotherapy Overview of Seizure Management in the Adult Emergency Department

Seizures are a common cause of emergency department visits, and approximately 28% of epilepsy patients present to an emergency department annually for treatment. This article will provide an overview of the pharmacotherapeutic management of seizures and anticonvulsant therapy for patients who present to the adult emergency department, including practical information for pharmacists covering or cross-covering this practice area. The benzodiazepines are reviewed as a class, including dosing strategies, pharmacodynamic considerations, and advantages and disadvantages of lorazepam, diazepam, and midazolam. Indications for the use of phenytoin and fosphenytoin will be reviewed, as well as dosing, adverse effects, and cost-effectiveness data. In addition, dosing, administration, pharmacokinetics, and adverse effects of phenobarbital, carbamazepine, and valproate will be discussed. Clinical indications for serum anticonvulsant concentration monitoring and subsequent calculation of loading doses from serum concentrations are reviewed. Since status epilepticus is a life-threatening emergency, its therapeutic management is reviewed, including the use of continuous infusion midazolam, pentobarbital, and propofol. There are many opportunities for clinical pharmacists to collaborate with other members of the health care team to optimize efficacy and minimize adverse effects of anticonvulsant agents in the emergency department setting.

Optimizing epilepsy management in teenagers

Optimal epilepsy management in teenage patients represents a particular challenge. These patients are often likely to respond more positively to a regimen that least disrupts their activities. In addition, as a patient group, they are more sensitive to peer perception. Current perceptions of older antiepilepsy drugs do not take into account frequent undesirable side effects or potential adverse interactions with other drugs. Furthermore, they often do not completely control seizures. Recent data suggest that not only do the newer antiepileptic drugs appear to be as efficacious as the older drugs, they also often have more favorable cognitive, cosmetic, and teratogenic side-effect profiles. In addition, newer antiepileptic drugs are being used more often in monotherapy. Successful management of epilepsy in teenagers requires that physicians not only understand the advantages that the newer antiepileptic drugs appear to provide but also consider the social impact of treatment on their patients.

Topiramate monotherapy as broad-spectrum antiepileptic drug in a naturalistic clinical setting

Topiramate was assessed in an open-label trial as broad-spectrum antiepileptic monotherapy, independently from the epilepsy type or syndrome. Adults and children aged 2 years and older, who were diagnosed with epilepsy within the last 5 years, treatment-naive or failing prior treatment with one antiepileptic drug (AED), received individually adjusted doses of topiramate, after escalation to 100mg/day over 4 weeks (maximum 400mg/day) or 3mg/kg/day over 6 weeks (maximum 9 mg/kg/day), respectively. Patients were followed for >or=7 months and optionally up to a maximum of 13 months. Data were analysed for all patients (n=692), as well as for focal (n=421) and generalized epilepsies (n=148). The median topiramate dose used was 125 mg/day in adults and 3.3mg/kg/day in children (<or=12 years). Overall, 80% of patients completed the 7-month study. During this period, 44.3% were seizure-free, while 76.3% achieved >or=50% reduction in mean monthly seizure frequency. Patients with focal and generalized epilepsies alike responded to treatment (73.9 and 83.8% with at least 50% seizure reduction): 39.4% of patients with focal epilepsy and 61.5% of those with generalized epilepsy were seizure-free. The mean monthly seizure frequency was significantly reduced versus baseline at all visits (p<0.001). Similar response rates were obtained from the 237 patients completing the 1-year observation period. During the mandatory 7-month period of study, 8.8% of patients reported insufficient tolerability as a reason for dropout. The most frequent adverse event was paraesthesia. Our results support findings that emerge from controlled studies that topiramate is effective and well tolerated when used as initial or second monotherapy. They also suggest that in a naturalistic setting, overall good retention on treatment and seizure freedom are observed at low doses in a broad spectrum of epilepsies.

New drugs for the treatment of epilepsy: a practical approach

The availability of new antiepileptic drugs has broadened the spectrum of medical treatment options in epilepsy. The new agents, together with established drugs, offer substantial choice for doctors treating patients with focal or generalised epilepsy. The newer antiepileptic drugs are not necessarily more effective but usually better tolerated than the traditional agents, mainly because of favourable pharmacokinetic profiles and fewer interactions. Because treatment options have increased, drug therapy can now be tailored to the requirements of individual patients. Nevertheless, significant safety and efficacy issues continue to exist and there is a need for the development of even better agents. This review describes the clinical use of the new antiepileptic drugs, but focuses in particular on monotherapy, the treatment of generalised seizures, teratogenicity, and the cognitive side effect profile of the newer compounds.

Single unprovoked seizures

Unprovoked seizures are common, affecting approximately 4% of the population by age 80. Only approximately 30% to 40% of patients with a first seizure will have a second unprovoked seizure (ie, epilepsy). Treatment with antiepileptic drugs (AEDs) should not be initiated unless the diagnosis of a seizure is firm. Decisions regarding treatment of single unprovoked seizures must balance seizure recurrence risk, the potential impact of a recurrent seizure, the likelihood of adverse effects of treatment, and patient preference. Risk factors for seizure recurrence include a history of remote neurologic insult, epileptiform abnormalities on electroencephalogram, focal structural lesion on neuroimaging, and family history of epilepsy. Adult patients with these risk factors have a recurrence risk of 60% to 70% and usually should be treated with an AED to prevent seizure recurrence. Without risk factors, the recurrence risk is 20% to 30%, and treatment depends on individual risk-to-benefit ratios and patient preference. Treatment of a first unprovoked seizure is often not necessary in childhood, especially if the seizure is part of a benign self-limited syndrome, such as benign Rolandic epilepsy of childhood. Treatment with an AED reduces the risk of seizure recurrence after a single unprovoked seizure. This must be balanced against the risk of adverse effects of AEDs. Treatment of the first seizure does not appear to affect the long-term prognosis of epilepsy. The choice of an AED should be guided by the seizure type and likely epilepsy syndrome diagnosis. Monotherapy is preferable. Standard AED options include phenytoin, carbamazepine, valproate, and phenobarbital. The newer AED, including gabapentin, lamotrigine, topiramate, oxcarbazepine, levetiracetam, and zonisamide, have good efficacy, favorable pharmacokinetic profiles, and often fewer adverse effects, supporting their use early in treatment. Not all of the newer AEDs are approved for use as monotherapy. Patients with single seizures should be counseled about seizure first aid and general safety measures, including precautions regarding swimming alone, engaging in high-risk activities, driving, possible seizure precipitation by photic stimuli (in generalized epilepsy), sleep deprivation, and alcohol.