[Affective disorders: News in chronobiological models]

Good news on chronobiological models of affective disorders are coming from a therapeutic innovation in the field of antidepressive action. Coming back to fundamentals by reconsidering the importance of the role of biological rhythms impairment in dysthymic pathology, a new interest bored on studies exploring short periodicities, so-called "ultradian" ones, on the basis of pharmacodynamics in the concept of therapeutic "window" of administration. The priority of circadian rhythms due to the major external biological desynchronization in depression, as well as the importance of sleep and alertness pathology, the spectacular relief of the depressive mood upon sleep deprivation, and the strong reduction of sleep need in mania, delayed exploration of ultradian exaltation of harmonic circadian components, marking a "buzz" of rhythmic structure and calling a "chronobiotic compound" which would be able to apply a "reset" to the temporal organisation. Another return to the origin leads to the experimental genomics, informing nor the "depressivity" but manic pathogenesis, in a mouse gene model which queries on the share of addictive and affective disorders.

Concurrent high-performance liquid chromatographic measurement of loxapine and amoxapine and of their hydroxylated metabolites in plasma

The dibenzoxazepine neuroleptic loxapine, its N-demethylated metabolite amoxapine, and their 7- and 8-hydroxymetabolites were measured simultaneously in plasma by reversed-phase high-performance chromatographic method. An original liquid-liquid extraction procedure was performed, consisting in coextraction of the substances together with a water-miscible solvent (acetonitrile) by a non-water-miscible solvent (toluene). The substances were separated on a 5-microm CN 25-cm column, and eluted with a mobile phase consisting of acetonitrile-acetic acid 0.5 N (30:70) and hexylamine (0.05%). They were detected by ultraviolet spectrophotometry at 310 nm. Clozapine was used as internal standard. Linearity was demonstrated in the range of 10 to 250 microg/l, and detection limits were found to be 3.5 to 6.3 microg/l according to the substance. Within-day repeatability ranged from 2.7% to 6.5%, and between-day reproducibility ranged from 0.9% to 20.2%. The extraction procedure provided a mean absolute recovery of 51.1% (range, 40.7% to 58.6%) with a mean coefficient of variation of 4.2%. This technique was applied to the concurrent determination of plasma concentrations of the compounds in 10 patients administered loxapine 75 to 600 mg daily. Steady state plasma levels of loxapine were significantly correlated with oral doses (n = 10, r = 0.858, p < 0.002). In conclusion, the method proved to be a convenient and reproducible procedure allowing the simultaneous measurement of loxapine, amoxapine, and their metabolites in patients.

Pilot investigation of thyrotropin-releasing hormone-induced thyrotropin and prolactin release in anxious patients treated with diazepam

Benzodiazepines have been reported to inhibit thyrotropin (TSH) and prolactin (PRL) secretion in response to stressful and pharmacologic stimuli in experimental animals. The current study investigates basal and thyrotropin-releasing hormone (TRH)-stimulated TSH and PRL release in anxious patients treated with diazepam. Six hospitalized patients having generalized anxiety or adjustment disorder with anxious mood (DSM III-R criteria) were treated during 1 week with diazepam (mean daily dose 33.3 mg). TRH testing was performed comparatively before and after 7 days of diazepam administration (with 250 micrograms protirelin and blood sampling at 15-min intervals over 60 min). Steady-state plasma levels of diazepam and its metabolite nordazepam (desmethyldiazepam) were determined by high-performance liquid chromatography. After 7 days of diazepam treatment, basal plasma levels of TSH and PRL were not affected compared with pretreatment values. Similarly, the time-course of TRH-induced TSH release was not modified by the treatment. By contrast, there was a trend to decrease in the TRH-induced PRL release, and the decrease in the PRL response to TRH on day 7 was significantly correlated with plasma nordazepam concentrations (rs = 0.943, p = 0.02). These preliminary results suggest that benzodiazepines, at therapeutic doses for the treatment of anxiety, may alter TRH-induced PRL release in humans.

Clonazepam in acute mania: time-blind evaluation of clinical response and concentrations in plasma

This study was performed to evaluate the optimal doses and clinical efficacy of clonazepam as a first-line drug in acute mania, as well as to determine its effective plasma concentrations. Clonazepam was administered orally to 11 newly admitted inpatients. On day 0, the loading dose was titrated upward according to the clinical global impression; the maintenance dose was calculated with intent to maintain the plasma level that had been achieved after initial dose escalation. Clinically based dose adjustments were allowed on days 4 and 7. Manic symptoms were scored on days 0, 4 and 14 according to a time-blind procedure; clonazepam plasma levels were measured by HPLC. On day 14, there was a significant decrease in manic symptoms and 66.7% of the patients who completed the trial were markedly improved. Steady-state plasma levels of clonazepam were significantly correlated with daily doses (rs = 0.795, P < 0.005) and therapeutic concentrations ranged between 6.5-83.9 micrograms/l. At the onset of therapy, the clinically titrated loading dose resulted in plasma concentrations within the narrow range of 18.9-34.0 micrograms/l. These results support the potential value of clonazepam in the short-term management of acute mania; the initial control of agitation was achieved with plasma drug levels in a remarkably narrow range as compared with the further control of mania.

An imidazopyridine anxiolytic alters glucose tolerance in patients: a pilot investigation

We have recently shown that compounds with high affinity for peripheral-type benzodiazepine receptors inhibited glucose-induced insulin secretion in vitro. We therefore performed an oral glucose tolerance test in anxious inpatients treated with the imidazopyridine derivative alpidem, which has been shown to display high affinity for these binding sites. The test was performed before and after 1 week of daily administration of the drug. As compared with pretreatment values, a significant alteration of the insulin response to glucose was observed. It is suggested that daily administration of alpidem, at therapeutically effective doses for the treatment of anxiety, may alter glucose tolerance.

A double-blind comparison of clonazepam and placebo in the treatment of neuroleptic-induced akathisia

The present study was designed to investigate the efficacy of clonazepam in neuroleptic-induced akathisia. Twelve patients were treated during 2 weeks with clonazepam or placebo in a double-blind randomized design. Akathisia was scored by an independent rater before and after treatment, as well as 1 week after medication withdrawal. Clonazepam (0.5-2.5 mg/day) induced a significantly higher reduction in the akathisia scores than placebo (p < 0.05). One week after stopping the drug, there was a partial but significant relapse in the treated group as compared with controls, in whom the symptoms remained stable. In addition, the clinical improvement was significantly correlated with the daily dose of clonazepam (rs = 0.827; p < 0.002). These results support the potential usefulness of clonazepam in the treatment of neuroleptic-induced akathisia and suggest an optimal daily dose in the range of 10-40 micrograms/kg.