Involuntary movement disorders associated with felbamate.

Two children developed involuntary movements while taking felbamate as an adjunct to their antiepileptic regimen. One exhibited choreoathetosis and the other an acute dystonic reaction. In both children the symptoms resolved with no recurrence after felbamate discontinuance.

Risperidone for aggression and self-injurious behavior in adults with mental retardation.

Risperidone has proven efficacy with reduced likelihood of causing extrapyramidal symptoms in the treatment of schizophrenia. Initial work suggests its utility in the management of aggression and self injury in patients with mental retardation. The use of risperidone in eight adult patients with moderate to profound mental retardation is described. Risperidone in these individuals was associated with significant reduction in aggression and self injurious behavior. Side effects were primarily those of sedation and restlessness. These cases illustrate the possible utility of risperidone in the treatment of aggression and self injury in adult patients with moderate to profound mental retardation.

Predicting unbound phenytoin concentrations in patients receiving valproic acid: a comparison of two prediction methods.

OBJECTIVE: To compare the predictive performance of 2 equations that estimate unbound (free) phenytoin plasma concentrations when valproic acid (VPA) and phenytoin are administered concurrently. DESIGN: Eighty-eight adults receiving VPA and phenytoin concurrently were included in the study. Steady-state plasma concentration measurements of total phenytoin, total VPA, and unbound phenytoin were collected prospectively in the inpatient group (group 1) and retrospectively in the outpatient group (group 2). Using the equations developed by Haidukewych and May, unbound phenytoin concentrations were calculated. The mean predicted unbound phenytoin concentrations then were compared with mean actual unbound phenytoin concentrations measured in the laboratory. Identical assays were performed to measure unbound phenytoin, total phenytoin, and VPA from each patient group. SETTING/PARTICIPANTS: Antiepileptic drug concentration measurements were collected from 43 inpatients (mean age 34.8 y) from the epilepsy unit at Abbott Northwestern Hospital and 45 outpatients (mean age 37.3 y) at the MINCEP Epilepsy Care clinic, Minneapolis, MN. MAIN OUTCOME MEASURES: Mean prediction error (MPE) and mean squared error (MSE) were calculated to determine which equation was the least biased and most precise in predicting unbound phenytoin when total VPA and phenytoin concentrations are known. Linear regression of predicted unbound phenytoin on measured unbound phenytoin values determined the correlation coefficients (r). A paired Student's t-test also was performed comparing mean predicted unbound phenytoin concentration with mean actual unbound phenytoin concentrations in both groups. RESULTS: The MPE from May's equation was -0.49 and -0.45 for groups 1 and 2, respectively; using the Haidukewych equation, MPE was -0.02 and 0.08 for groups 1 and 2, respectively. The MSE using May's equation was 0.34 for both groups. Using the Haidukewych equation, group 1 MSE was 0.07, and for group 2, 0.12. Correlation coefficients were more than 0.91 (p < 0.001) from each equation in both patient groups. In group 1, mean actual unbound phenytoin concentration was 2.02 micrograms/mL; May's equation predicted 1.52 micrograms/mL (p < 0.001) and the Haidukewych equation predicted 2.00 micrograms/mL (p = 0.64). In group 2, mean actual unbound phenytoin concentration was 2.10 micrograms/mL; May's equation predicted 1.65 micrograms/mL (p < 0.001) and the Haidukewych equation predicted 2.18 micrograms/mL (p = 0.11). CONCLUSIONS: Haidukewych's equation predicts unbound phenytoin concentrations with the least bias and most precision with statistical significance. May's equation consistently underpredicted unbound phenytoin concentrations. Because unbound phenytoin fraction is not constant (and usually more than the expected 10%) in patients comedicated with VPA, unbound phenytoin concentrations cannot be predicted even though total VPA and phenytoin concentrations are known. If unbound phenytoin concentrations cannot be readily measured, Haidukewych's equation is a reliable predictor of unbound phenytoin concentrations.

Clinical and economic aspects of risperidone treatment in adults with mental retardation and behavioral disturbance.

Risperidone, in conjunction with behavioral interventions, was used to reduce aggression and assault, self-injury, and property destruction in 33 institutionalized adults with mental retardation. Target behavior frequencies, global assessments by staff, wages earned by patients, and the institution's costs for assault-related injury to staff and lost work time were evaluated before and after initiation of risperidone treatment. Risperidone (1-8 mg/day) was associated with a 50 percent or greater reduction in at least one target behavior frequency in 61 percent of patients. After 6 months of treatment, 85 percent of patients were rated "improved" and 15 percent were rated "unchanged." Treated patients' wage earnings increased by 37 percent. The number of staff work days lost because of assault by treated patients decreased from 444 during the 6 months before initiation of risperidone to 29 during the 6 months after initiation. Sedation, pseudoparkinsonism, possible akathisia, and weight gain were noted in 9-12 percent of patients. No patients were withdrawn from risperidone because of intolerable side effects or lack of efficacy. The results of this evaluation suggest that risperidone is effective and well tolerated in this population.