Effects of dopamine agonists on Cebus apella monkeys with previous long-term exposure to fluphenazine.

Sixty-one weeks after 48 weeks of treatment with fluphenazine decanoate or placebo, 37 socially living Cebus apella monkeys were evaluated for differences in dopaminergic sensitivity by exposure to 0.75 mg/kg, i.m. of amphetamine (AMPH) (indirect agonist) and apomorphine (APOM) (direct agonist). The fluphenazine-treated animals differed (p < or = 0.05) from control animals on some hourly measures of composite behavioral variables (CBVs). Animals exposed to fluphenazine showed a greater decrease in the aggressiveness CBV and a smaller decrease in self- and environment-directed behaviors than placebo animals. CBVs for normal locomotion and directs affiliation showed no significant differences. The fluphenazine-treated group showed greater agonist induction of stereotypic behavior (p < or = 0.01), and larger decreases in prolactin response to AMPH (p < or = 0.05). Our findings indicate that following extended treatment with an antipsychotic there is increased sensitivity to dopamine, as evidenced by stereotypies and possibly hypophyseal responsiveness.

Cognitive effects of milacemide and methylphenidate in healthy young adults.

Cognitive effects of the novel glycine prodrug milacemide (400 mg), the catecholaminergic agonist methylphenidate (20 mg), and placebo were evaluated in 48 healthy young adults. Throughout a 6-h drug treatment day, subjects repeatedly performed tests of target-detection vigilance, immediate and delayed verbal free recall, and Buschke Selective Reminding; total free recall and forced-choice recognition tests were administered at the end of the day. Significant improvement in both vigilance reaction time and Selective Reminding Sum Recall was observed in the methylphenidate group. Contrary to expectations, the milacemide group evidenced significant declines in both vigilance perceptual sensitivity and free-recall difference scores (delayed-immediate). Vigilance reaction times significantly decreased over repeat testing in all groups, but only the methylphenidate group differed from placebo. The reaction-time functions for milacemide and placebo were similar, suggesting arousal was not diminished under milacemide and could not account for the cognitive decrements. No significant drug effects obtained for total free recall or recognition performance. Although the glycine prodrug milacemide was ineffective as a cognitive enhancer, the involvement of the NMDA receptor in memory function reported in the literature supports continued exploration of other approaches for manipulating NMDA receptor activity.

Efficacy of benztropine therapy for drooling.

This study assessed the efficacy of synthetic anticholinergic benztropine and incidence of side-effects in 20 developmentally-disabled patients with severe drooling. The double-blind, placebo-controlled, crossover protocol included one-week baseline, two-week placebo and two-week benztropine conditions (mean dose 3.8 mg). A significant decrease in drooling during the benztropine condition relative to placebo was demonstrated and conservative response rates (calculated by deleting placebo responders), ranged up to 65 to 70 per cent. For patients completing the protocol the incidence of side-effects did not differ across conditions and minor problems such as a dry mouth were eliminated by small dose adjustments. More serious cholinergic side-effects, which resolved within 24 to 48 hours, necessitated discontinuation of the drug in three patients. This study demonstrates that synthetic anticholinergics can provide an important therapeutic alternative to surgical and behavioral therapies for drooling.

Mianserin pharmacokinetics and behavior in hyperkinetic children.

The present study was conducted to derive pediatric mianserin pharmacokinetic parameters, which were compared to those from healthy young adults, and to obtain preliminary information regarding the utility of mianserin for the management of hyperkinesis in children. The sample consisted of six prepubescent children with hyperkinetic behavior disorders who had not responded, or had developed tolerance to, stimulant medication. Mianserin pharmacokinetics were derived from plasma samples obtained over a 36- to 50-hour period following a single oral dose which ranged from 0.28 to 0.72 mg/kg. Children evidenced a significantly faster elimination half-life and a significantly smaller apparent kinetic volume of distribution than did adults, whereas maximum plasma concentration, time to maximum concentration, and apparent oral plasma clearance were similar. Ratings of behavioral deviance were obtained from teachers and parents during placebo and mianserin titration to a maximum dose of 40 mg/day. Although half the children showed some decrease in hyperactivity ratings, the small sample size and high variability of response preclude conclusions regarding the efficacy of mianserin for childhood hyperkinesis. Possible side effects in our sample included akathisia, excitability, insomnia, and migraine-like headache, as well as cardiovascular effects of tachycardia and two instances of minor electrocardiographic change. Our pharmacokinetic findings will be of import should mianserin prove useful for such childhood disorders as depression and/or enuresis.(ABSTRACT TRUNCATED AT 250 WORDS)