• It is clinically useful to have a table listing the equivalent doses of the various neuroleptics to a standard, such as chlorpromazine. This article derives such data by reviewing doubleblind controlled studies that used a flexible dosage schedule of neuroleptics in treating schizophrenic patients. Each neuroleptic is then converted to 100-mg chlorpromazine equivalents. This empirically derived dosage comparability table is compared with a similar table derived from the opinions of experts. Since these comparable doses produce equivalent amounts of antipsychotic activity, the cost to provide such medication was then calculated, and a table comparing the costs of the different neuroleptics was constructed. In absolute amounts, the cost differences between drugs are small. However, for any drug, large savings accrue when the largest possible capsule or tablet to achieve the desired dose is prescribed.

Comparative doses and costs of antipsychotic medication.

Hospital psychiatry has evolved from long-term "treatment" programs that were primarily custodial to the successful pharmacological treatment of acute psychotic episodes. Unfortunately, many patients still return to the hospital with relapses. This so-called revolving door syndrome draws attention to the critical importance of preventing as well as treating acute episodes. In the first part of this overview, the author reviews the clinical literature on prophylactic treatment of schizophrenia with maintenance antipsychotic drugs. The second part will review the literature on prophylactic treatment of affective disorders with lithium and tricyclics. In the opinion of the author these drugs provide the potential for truly preventive psychiatry.

Overview: maintenance therapy in psychiatry. I. Schizophrenia

We review evidence from randomized, placebo-controlled studies of patients with schizophrenia or schizoaffective disorder, which compared 2 or more doses of an antipsychotic to calculate the dose-response curve for each first-generation (typical) antipsychotic (FGA) or second-generation (atypical) antipsychotic (SGA) and as a group (based on dose equivalence). We identified the near-maximal effective dose (ED; ie, the threshold dose necessary to produce all or almost all the clinical responses for each drug). In randomized, fixed-dose studies of SGAs, the near-maximal efficacy dose for olanzapine may be greater than 16 mg; for risperidone, it is 4 mg; and for ziprasidone, it is 120 mg. Risperidone at 2 mg daily is 50% less efficacious than higher doses. Olanzapine at about 6 mg is approximately 33% less effective than higher doses. Aripiprazole at 10 mg daily was fully efficacious. Doses of clozapine well above 400 mg are necessary for optimal treatment of many schizophrenia patients. We found 3.3 to 10 mg haloperidol to be the near-maximal ED range. We find no evidence that doses higher than these are more effective. We failed to find that high doses of haloperidol (or all other first-generation comparison drugs converted to equivalent doses) were less effective than medium doses (3.3 to 10 mg). While high-dose FGAs are not less effective, we feel it is important not to avoid using high dose to avoid excessive toxicity.

/pdf/dose-response-and-dose-equivalence-of-antipsychotics-175oxp3lmy.pdf

Dose response and dose equivalence of antipsychotics.

The author reviews six topics relevant to the drug treatment of schizophrenia. The quantitative effectiveness of promazine is of interest with respect to the structural models of the phenothiazines and the dopamine theory of schizophrenia. The quantitative effectiveness of antipsychotic drugs is also important in evaluating new agents and therefore relevant to a discussion of two newly released neuroleptics, molindone and loxapine. The author's discussion of high-dose treatment of typical acute schizophrenics or treatment-resistant patients reviews the available data and calls attention to the fact that these areas of pharmacologic research have not received sufficient attention.

Recent Developments in the Drug Treatment of Schizophrenia

BACKGROUND Antipsychotic drugs are usually given orally but compliance with medication given by this route may be difficult to quantify. The development of depot injections in the 1960s gave rise to extensive use of depots as a means of long-term maintenance treatment. Perphenazine decanoate and enanthate are depot antipsychotics that belong to the phenothiazine family and have a piperazine ethanol side chain. OBJECTIVES To assess the effects of depot perphenazine decanoate and enanthate versus placebo, oral antipsychotics and other depot antipsychotic preparations for people with schizophrenia in terms of clinical, social and economic outcomes. SEARCH STRATEGY We updated previous searches of the Cochrane Schizophrenia Group Register (June 1998), Biological Abstracts (1982-1998), the Cochrane Library (Issue 2, 1998), EMBASE (1980-1998), MEDLINE (1966-1998), and PsycLIT (1974-1998) by searching the Cochrane Schizophrenia Group Register (March 2004). References of all identified trials were also inspected for more studies and industry contacted. SELECTION CRITERIA We compared randomised clinical trials focusing on people with schizophrenia where depot perphenazine decanoate and enanthate, oral antipsychotics or other depot preparations. DATA COLLECTION AND ANALYSIS We reliably selected studies, quality rated them and extracted data. For dichotomous data we estimated the Relative Risk (RR) with the 95% confidence intervals (CI). Where possible, we calculated the number needed to treat statistic (NNT). Analysis was by intention-to-treat. MAIN RESULTS Only four studies (Ahlfors 1980, Eufe 1979, Knudsen 1985c, Tegeler 1979), randomising a total 313 people could be included in this review and this combined with an overall lack of usable data limits any interpretation of results. Perphenazine enanthate was not significantly any better or worse than other depot antipsychotics in most of the main outcomes such as global state, relapse or leaving the study early. We found some differences favouring the control groups for adverse effects. One study (Ahlfors 1980) of six months' duration (n=172), compared perphenazine enanthate to clopenthixol decanoate. There were no differences between the two groups for outcomes of global improvement, relapse and leaving the study early. More people in the perphenazine enanthate group, however, required anticholinergic drugs than those allocated to clopenthixol decanoate (RR 1.12 CI 1.0 to 1.2, NNT 10).A single study (n=64, duration six weeks) compared perphenazine enanthate and its longer acting decanoate ester. Data on relapse and leaving the study early failed to show convincing differences. The enanthate group, however, experienced more movement disorders (RR 1.36, CI 1.1 to 1.8 NNT 5) than those allocated the decanoate ester of the same drug and required more anticholinergic drugs (RR 1.47 CI 1.1 to 2.0, NNT 4). AUTHORS' CONCLUSIONS Depot perphenazine is in clinical use in the Nordic countries, Belgium, Portugal and the Netherlands. At a conservative estimate, a quarter of a million people suffer from schizophrenia in those countries and could be treated with depot perphenazine. The total number of participants in the four trials with useful data is 313. None of the studies observed the effects of oral versus depot antipsychotic drugs. Until well conducted and reported randomised trials are undertaken clinicians will be in doubt as to the effects of perphenazine depots and people with schizophrenia should exercise their own judgement or ask to be randomised.

/pdf/depot-perphenazine-decanoate-and-enanthate-for-schizophrenia-1k2gtz3gph.pdf

Depot perphenazine decanoate and enanthate for schizophrenia.

Treatment of resistant schizophrenics with extreme high dosage fluphenazine hydrochloride.

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Treatment of resistant schizophrenics with extreme high dosage fluphenazine hydrochloride.