Pharmacokinetic-pharmacodynamic modeling of tolerance to the prolactin-secreting effect of chlorprothixene after different modes of drug administration. (1/9)

The objective of this study was the construction of a pharmacokinetic-pharmacodynamic model to describe the effects of chlorprothixene on prolactin secretion and the time-dependent alterations in the concentration-effect relationship due to tolerance development. Prolactin and chlorprothixene serum concentrations were determined in eight healthy men for up to 72 h after the intravenous and oral administration of chlorprothixene. An integrated pharmacokinetic model and a physiological indirect pharmacodynamic/tolerance model were applied to describe the prolactin-secreting effect of chlorprothixene. A three-compartment model served as pharmacokinetic model. The pharmacodynamic and tolerance model accounted for the baseline effect, the effect induced by the drug, and the regulatory mechanism that opposes the effect of the drug. This model adequately characterized the prolactin response after intravenous and oral drug administration of each individual by the sensitivity (dissociation constant), the efficacy (maximal prolactin secretion rate), the extent, and the rate of tolerance development. We speculate that this approach improves the quality of neuroendocrine challenge tests to determine the subject's sensitivity to drugs and the time course of adaptation.  (+info)

EFFECT OF CHLORPROTHIXENE IN PATIENTS WITH PARANOID SYMPTOMS. (2/9)

Chlorprothixene, a thioxanthine derivative, claimed to have broad-spectrum antipsychotic properties, was compared with phenothiazine derivatives in the setting of a psychiatric admission service and aftercare clinic.In 32 female patients with paranoid symptoms, chlorprothixene in high dosage ranges (200 to 1200 mg. daily) was found to be as effective as similar doses of chlorpromazine in controlling the symptoms; fewer side effects were noted.  (+info)

THE INCREASE IN THE TOXICITY OF YOHIMBINE INDUCED BY IMIPRAMINE AND OTHER DRUGS IN MICE. (3/9)

In mice, yohimbine appears to accentuate the normal "alarm" reactions (alerting, flight) to external stimuli. Imipramine increases this effect and at the same time converts a non-lethal dose of yohimbine into a lethal one. The effect of imipramine is greatly reduced by adrenalectomy or by treatment with reserpine, syrosingopine, ganglion-blocking drugs or adrenaline antagonists acting on sympathetic beta-receptors. Hypnotic, anti-convulsant or anaesthetic agents, tetrabenazine or antagonists of 5-hydroxytryptamine do not reduce the imipramine effect. A variety of drugs which, like imipramine, are known to interfere with the tissue binding of noradrenaline also increase the toxicity of yohimbine. Yohimbine significantly reduces brain noradrenaline content; adrenal catechol amines are slightly reduced. The results suggest that yohimbine releases noradrenaline from stores or nerves as a consequence of increased central sympathetic activity. Imipramine increases the actions and toxicity of yohimbine by increasing the effects of the released noradrenaline on beta-receptors. The lethal effects of a high dose of yohimbine alone are not reduced by any of the treatments tested, and appear not to result from activation of sympathetic mechanisms.  (+info)

GASTROINTESTINAL DISTURBANCES ASSOCIATED WITH WITHDRAWAL OF ATARACTIC DRUGS. (4/9)

The psychological effects of abrupt withdrawal of ataractic drugs have been studied by others. Physical symptoms also occur under such circumstances and include abdominal pain, nausea and vomiting. Forty patients were divided into four groups of 10, each group receiving one of the following drugs: chlorpromazine, thioridazine, perphenazine or chlorprothixene. This medication was then suddenly withdrawn. In each of the chlorpromazine and thioridazine groups, three patients had gastrointestinal symptoms within 48 hours, lasting one to eight days. One patient on chlorprothixene, 450 mg. daily, experienced symptoms for six days. Perphenazine withdrawal produced no such symptoms. Thioridazine has little antiemetic action but perphenazine is prescribed for vomiting; hence it seems unlikely that the reported symptoms are due to a rebound action on the vomiting centre.These findings are relevant to the situation of withdrawal of ataractics prior to administration of anesthetics and to drug studies involving cross-over from an active compound to a placebo. The increasing use of ataractics suggests that this additional diagnostic possibility should be considered in the presence of obscure gastrointestinal symptoms.  (+info)

A COMPARISON OF IMIPRAMINE, CHLORPROMAZINE AND RELATED DRUGS IN VARIOUS TESTS INVOLVING AUTONOMIC FUNCTIONS AND ANTAGONISM OF RESERPINE. (5/9)

Seven structurally-related compounds consisting of three antidepressant drugs (imipramine, desmethylimipramine and amitriptyline), three tranquillizing agents (promazine, chlorpromazine and chlorprothixene) and a hybrid, desmethylpromazine, have been examined in a series of tests involving autonomic functions and antagonism of reserpine. Activities of the compounds in antagonizing reserpine-induced ptosis in rabbits and prolongation of alcohol hypnosis in mice give good correlation with their clinical actions, whilst their activities in augmenting excitation of rats by amphetamine and yohimbine toxicity in mice, and in reversing reserpine-induced bradycardia in rats offer further evidence for drug-induced sensitization to adrenergic or tryptaminic mechanisms, which is not however specific for antidepressant agents. No evidence has been obtained to indicate that a central parasympatholytic action is an important component of the antidepressant activity of imipramine and related drugs.  (+info)

Efficacy, tolerability, and preference of mirtazapine orally disintegrating tablets in depressed patients: a 17-week naturalistic study in Lithuania. (6/9)

Mirtazapine is an established antidepressant with well-documented efficacy demonstrated in controlled clinical trials. However, the gap between the results obtained in controlled clinical trials and everyday clinical practice exists. Therefore, the importance of naturalistic studies in psychiatry is becoming recognized. The aim of present naturalistic study was to acquire data on efficacy, safety, and preference of mirtazapine orally disintegrating tablets during a 17-week treatment of depression. This prospective, open-label, multicenter study in patients with mild to severe depression was conducted at 47 mental health centers of Lithuania by 78 psychiatrists. Patients were initially given 15 mg or 30 mg of mirtazapine orally disintegrating tablets; the maximum allowed dose was 45 mg per day. The primary efficacy measure was the total score on the Hamilton Depression Rating Scale-17 (HAMD-17), the Clinical Global Impression-Severity (CGI-S), and Clinical Global Impression-Improvement (CGI-I) scales. Tolerability was primarily measured by assessing the incidence of treatment-emergent adverse events. Patients were evaluated at baseline, at weeks 1, 5, 9, 13, and 17. A total of 779 patients (595 women [76.4%] with a mean [SD] age of 50.2 [13.65] and 184 men [23.6%] with a mean [SD] age of 52.4 [14.6] years) were enrolled into the study; 687 (88.2%) patients completed the study. The mean (SD) daily dose of mirtazapine orally disintegrating tablets was 29.0 (3.8) mg. The mean total (SD) HAMD-17 score improved significantly from 25.7 (4.6) to 7.3 (4.3) (P<0.005). At each visit, the mean HAMD-17 score was significantly lower than that at the preceding visit. At week 17, remission (HAMD-17 score < or =7) was observed in 436 (56%) patients. The mean (SD) CGI-S score improved significantly from 4.9 (1.0) at baseline to 1.5 (0.6) at endpoint (P<0.001). According to the CGI-I assessments, 621 patients (89.4%) improved and improved very much. The vast majority of patients (80%) preferred the new formulation of mirtazapine - mirtazapine orally disintegrating tablet. Treatment-emergent adverse events occurred in 106 patients (13.6%). The most frequent adverse events were weight gain, sedation, dizziness, and dry mouth. In this study conducted in Lithuania with depressed patients, a significant improvement was shown in all efficacy measures. In addition, mirtazapine orally disintegrating tablet was a well-tolerated and preferable formulation for the treatment of depressed patients.  (+info)

Solvent dependence of the photophysical properties of 2-chlorothioxanthone, the principal photoproduct of chlorprothixene. (7/9)

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Diagnosis and treatment of conduct disorder related to frontal lobe syndrome in a 16-year-old girl. (8/9)

Conduct disorders are the most frequent psychiatric diagnosis in the pediatric and adolescent population, with different etiology and difficult to treat. Delinquent, aggressive, and impulsive behavior, lack of empathy and inability to predict possible consequences of the behavior lead to significant desadaptation and danger for these patients. In clinical practice, focus is usually given on social and psychological causes of conduct disorders ignoring possible biological factors in etiology and pathophysiology. A clinical case described in this article shows the linkage between frontal brain dysfunction and behavioral symptoms. The first clues of organic brain disorder were multiple and severe symptoms of disinhibition resistant to treatment with dopaminergic drugs and the results of neuropsychological testing. Computed tomography, magnetic resonance imagining, and single-photon emission computed tomography findings were minor and not supported by associated neurological symptoms. However, the location of alterations of brain structure and perfusion significantly correlated with psychopathology. Clarification of the organic cause of the conduct disorder allowed choosing an effective strategy of psychopharmacologic treatment. A positive clinical effect was achieved after switching the treatment from dopaminergic antipsychotic drugs to carbamazepine, which modulates the GABAergic system. Presenting this clinical case, we intended to emphasize the importance of careful attention to the findings of neurovisual and neuropsychological testing diagnosing conduct disorders and individually choosing the most effective psychopharmacologic treatment.  (+info)

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