Treatment of acute psychosis with non-neuroleptic agents

Analytic Reviews : Rapid Tranquilization of the Agitated Intensive Care Unit Patient

Agitation in intensive care unit patients is a problem that is often ignored or undertreated. The presence of agita tion warrants a thorough investigation for underlying causes (e.g., metabolic and systemic abnormalities, drug intoxication or withdrawal, hypoxia, and pain) so that the precipitating disturbances can be identified and cor rected. When these conservative measures fail to con trol a patient's agitation, it may be necessary to resort to mechanical restraint and sedating medication. The au thors present guidelines for the pharmacological man agement of agitation and the risks and benefits associ ated with the use of specific agents.

The Role of Melatonin in the Antipsychotic and Motor-Side Effects of Neuroleptics: A Hypothesis

Three phenomena concerning the antipsychotic action of classic neuroleptic drugs have not been adequately explained by the dopamine hypothesis: (1) administration of neuroleptic drugs is commonly associated with an initial period of 3-6 weeks prior to demonstration of antipsychotic effects; (2) similarly, neuroleptic-induced Parkinsonism commonly emerges only after several weeks of neuroleptic therapy; (3) moreover, Parkinsonism may disappear despite continuous neuroleptic treatment. An understanding of these phenomena might shed new light into the nature of the antipsychotic actions of these agents, and hence the pathophysiology of schizophrenia. We propose that the increase in melatonin secretion, which occurs with the initiation of neuroleptic therapy, may be responsible for the delay in the antipsychotic effects of neuroleptics and may also account for the lag in the development of drug-induced Parkinsonism as well as its disappearance. The implications of this hypothesis for the treatment of schizophrenia and the prophylaxis of drug-induced Parkinsonism are discussed.

The effects of pentazocine, a kappa agonist, in patients with mania

Past evidence suggests that activation of kappa opiate receptors may lower mood. However, kappa agonists may also induce psychotomimetic symptoms. We tested the effects of the kappa agonist pentazocine in patients in the manic phase of bipolar disorder to determine if pentazocine might reduce symptoms of mania without worsening psychosis. In an open-label, add-on, single-day acute-dose study, ten in-patients with bipolar disorder, type 1, hospitalized for mania received two 50 mg doses of pentazocine 2 h apart. Symptoms of mania were reduced 1 h after each dose, 44% after the first dose and 41% 1 h after the second dose (F=3.69, p=0.01). No adverse effects, including psychotomimetic effects were observed or reported. Sedation was minimal. Further study of pentazocine and other kappa agonists in mania seems warranted.

Treatment guidelines for psychotropic drug use in pregnancy

Despite the apparent risks of psychotropic drug exposure in pregnancy, many pregnant women receive psychotropics. The major concerns associated with the use of antipsychotics, antidepressants, benzodiazepines, and lithium carbonate in pregnancy are reviewed, with clinical approaches for assessing the relative risks and benefits of treatment of psychiatrically ill pregnant patients and for choosing and instituting therapy with these agents.

A fixed dose study of the plasma concentration and clinical effects of thioridazine and its major metabolites

Fifty-three patients in an acute episode or exacerbation of psychosis were given thioridazine 200 or 400 mg daily for 2 weeks. Thioridazine and its active metabolites, mesoridazine and sulforidazine, were estimated in plasma by high performance liquid chromatography (HPLC) and radioreceptor assay (RRA). One week after institution of treatment, plasma concentrations of drug were stable in the morning 12h after dosing. Drug levels varied widely between patients, but in all patients the relative level of thioridazine to mesoridazine was about one half and thioridazine to sulforidazine was about two fold. Estimates of neuroleptic activity by RRA and the weighted sum of thioridazine, mesoridazine and sulforidazine by HPLC were very similar. Plasma concentration of parent compound, metabolites, or the sum of active substances as estimated by HPLC or RRA, showed only modest correlations (rs = 0.10-0.22, all NS) to the degree of improvement as measured by change on the Brief Psychiatric Rating Scale. Significant correlations were observed between plasma concentrations of drug and side effects, including dry mouth, blurred vision, or total rating on the Somatic Symptoms Scale. Even patients receiving the lowest dose and achieving the lowest plasma concentrations of drug showed considerable improvement. There was suggestive evidence that the patients achieving the highest plasma levels of drug did not have the best clinical outcome. These and similar observations from other studies suggest that currently used doses of neuroleptics may be excessive. Optimal drug effects as well as stronger relationships between dose, drug concentration, and clinical therapeutic effects might best be sought at doses below those in common use.

Neuroleptic drugs in the treatment of acute psychosis: how much do we really know?

The efficacy of neuroleptic antipsychotic drugs has been well demonstrated and neuroleptics are the standard treatment of acute psychosis. However, important aspects of neuroleptic treatment, including course of response, optimal doses, and mechanism of action, remain poorly studied or controversial. Placebo-controlled studies of the onset of the response of acute psychosis to neuroleptics are few and yield conflicting results. Studies of the relationship of doses and blood levels to the therapeutic effects of neuroleptics suggest that the optimal range of doses and levels is narrow and that commonly used doses are too high. Finally, studies of the mechanism of action of neuroleptics suggest that the dopamine hypothesis is based on unsupported assumptions concerning drug effects, drug distribution, and effective doses of drug. Alternative hypotheses, that the antipsychotic effects of the neuroleptics are mediated, at least in part, through alpha 1-adrenergic or serotonin 5-HT2 receptor antagonism, are reviewed. The evidence regarding these issues and controversies is discussed, and specific approaches to increase our understanding and enhance our use of the neuroleptics are suggested.

In vivo potencies of antipsychotic drugs in blocking alpha 1 noradrenergic and dopamine D2 receptors: implications for drug mechanisms of action

In addition to being dopamine antagonists, all antipsychotic drugs are potent antagonists of alpha-1 noradrenergic receptors. Nevertheless, the contribution of alpha blockade to the clinical therapeutic effects of the antipsychotic drugs has never attracted extensive study. In particular, the relative alpha-1 noradrenergic antagonist potency of antipsychotic drugs has rarely been determined in vivo during extended treatment, although such treatment would provide a better model of clinical drug effects than the determination of potencies in in vitro systems, such as assays of competition for binding sites in tissue homogenates, as is most often done. To estimate the physiological efficacy of antipsychotic drugs as dopamine and alpha adrenergic antagonists, we treated rats for four weeks with daily IP injections of the following antipsychotic drugs: Fluphenazine, 1 mg/kg; haloperidol, 1 mg/kg; chlorpromazine, 25 mg/kg; thioridazine, 25 mg/kg; and clozapine, 25 mg/kg. Effective antagonism should lead to an increase in density of the relevant receptors. After two drug-free days, rats were sacrificed and the affinity and density of dopamine D2 and alpha-1 noradrenergic receptors were determined in striatum and brain exclusive of striatum, respectively. Alpha 1 noradrenergic receptor density but not dopamine receptor density was increased after all treatments. Thus, preliminary experiments with this in vivo model suggest that all antipsychotic drugs are effective antagonists at alpha 1 noradrenergic receptors, while not all are effective antagonists at dopamine D2 receptors.