Levetiracetam influences human motor cortex excitability mainly by modulation of ion channel function--a TMS study.

PURPOSE: Levetiracetam (LEV) is a new compound with anticonvulsive efficacy in focal and generalized epilepsies. Recent in vitro studies suggest LEV to act as a selective N-type-calcium-channel blocker. METHODS: We used transcranial magnetic stimulation (TMS) in order to investigate if ion-channel blockade is relevant to the inhibitory CNS effects of LEV in vivo and if motor thresholds (MTs) are a valid TMS parameter to detect this mode of action. In a double blind, placebo-controlled, crossover study, the effects of single oral doses of 500 and 2000 mg LEV on motor thresholds, recruitment curves (REC), cortical induced silent period (CSP) and on intracortical inhibition (ICI) and facilitation (ICF) were studied in 10 healthy subjects. RESULTS: A significant increase of motor thresholds was noticed after 2000 mg LEV as compared to placebo. The recruitment curve showed a trend towards motor evoked potential (MEP) amplitude reduction after LEV. LEV had no significant effect on CSP or on intracortical excitability as measured by inhibition and facilitation. CONCLUSIONS: We conclude that the modulation of ion-channel function, reflected by motor threshold elevation and a trend towards recruitment curve suppression, is relevant to the inhibitory CNS effects of LEV in vivo, and therefore, may contribute to the anticonvulsive efficacy of LEV. GABAergic or glutamatergic mechanisms seem to be less important in vivo as measured by TMS.

Patient preferences for disease-modifying drugs in multiple sclerosis therapy: a choice-based conjoint analysis.

OBJECTIVES: With an increasing number of disease-modifying treatments (DMTs) for multiple sclerosis (MS), patient preferences will gain importance in the decision-making process. We assessed patients' implicit preferences for oral versus parenteral DMTs and identified factors influencing patients' treatment preference. METHODS: Patients with relapsing-remitting MS (n = 156) completed a questionnaire assessing treatment preferences, whereby they had to decide between pairs of hypothetical treatment scenarios. Based on this questionnaire a choice-based conjoint analysis was conducted. RESULTS: Treatment frequency and route of administration showed a stronger influence on patient preference compared with frequency of mild side effects. The latter attribute was more important for treatment-naïve patients compared with DMT-experienced patients. The higher the Extended Disability Status Scale score, the more likely pills, and the less likely fewer side effects were preferred. Pills were preferred over injections by 93% of patients, when treatment frequency and frequency of side effects were held constant. However, preference switched to injections when pills had to be taken three times daily and injections only once per week. Injections were also preferred when pills were associated with frequent side effects. CONCLUSIONS: Our results suggest that route of administration and treatment frequency play an important role in the patients' preference for a given DMT.

Once-daily transdermal rivastigmine in the treatment of Alzheimer's disease.

During the past decade, transdermal delivery systems (TDS) have become increasingly important for treating neurologic and psychiatric disorders. The rivastigmine patch was the first patch to be approved to treat Alzheimer's disease (AD). The 9.5 mg/24 h patch has equal efficacy to the capsules and reduces gastrointestinal adverse events, such as nausea and vomiting, by two-thirds. This treatment is well tolerated by patients because drug delivery is even and continuous, reducing fluctuation in drug plasma level, and attenuating the development of centrally mediated cholinergic side effects. Furthermore, once-a-day application of the patch enables an easy treatment schedule, ease of handling, infrequent skin irritations, and a patient- and caregiver-friendly mode of administration. Improved compliance with a subsequent drug administration may contribute to better clinical efficacy, reduce caregiver burden, result in a slower rate of institutionalization, and lead to a decrease in healthcare and medical costs. Because of these advantages, the rivastigmine patch has enabled great progress in the treatment of AD, and represents an excellent alternative to the orally administered cholinesterase inhibitors.