Clinical effects and drug concentrations in plasma and cerebrospinal fluid in psychotic patients treated with fixed doses of chlorpromazine

Optimisation of pharmacotherapy in psychiatry through therapeutic drug monitoring, molecular brain imaging and pharmacogenetic tests: focus on antipsychotics

BACKGROUND

For psychotic disorders (i.e. schizophrenia), pharmacotherapy plays a key role in controlling acute and long-term symptoms. To find the optimal individual dose and dosage strategy, specialized tools are used. Three tools have been proven useful to personalize drug treatments: therapeutic drug monitoring (TDM) of drug levels, pharmacogenetic testing (PG), and molecular neuroimaging.

METHODS

In these Guidelines, we provide an in-depth review of pharmacokinetics, pharmacodynamics, and pharmacogenetics for 50 antipsychotics. Over 30 international experts in psychiatry selected studies that have measured drug concentrations in the blood (TDM), gene polymorphisms of enzymes involved in drug metabolism, or receptor/transporter occupancies in the brain (positron emission tomography (PET)).

RESULTS

Study results strongly support the use of TDM and the cytochrome P450 (CYP) genotyping and/or phenotyping to guide drug therapies. Evidence-based target ranges are available for titrating drug doses that are often supported by PET findings.

CONCLUSION

All three tools discussed in these Guidelines are essential for drug treatment. TDM goes well beyond typical indications such as unclear compliance and polypharmacy. Despite its enormous potential to optimize treatment effects, minimize side effects and ultimately reduce the global burden of diseases, personalized drug treatment has not yet become the standard of care in psychiatry.

Clinical Pharmacokinetics and Pharmacodynamics of Drugs in the Central Nervous System

Despite contributing significantly to the burden of global disease, the translation of new treatment strategies for diseases of the central nervous system (CNS) from animals to humans remains challenging, with a high attrition rate in the development of CNS drugs. The failure of clinical trials for CNS therapies can be partially explained by factors related to pharmacokinetics/pharmacodynamics (PK/PD), such as lack of efficacy or improper selection of the initial dosage. A focused assessment is needed for CNS-acting drugs in first-in-human studies to identify the differences in PK/PD from animal models, as well as to choose the appropriate dose. In this review, we summarize the available literature from human studies on the PK and PD in brain tissue, cerebrospinal fluid, and interstitial fluid for drugs used in the treatment of psychosis, Alzheimer's disease and neuro-HIV, and address critical questions in the field. We also explore newer methods to characterize PK/PD relationships that may lead to more efficient dose selection in CNS drug development.

Chlorpromazine dose for people with schizophrenia

BACKGROUND

The World Health Organization (WHO) Model Lists of Essential Medicines lists chlorpromazine as one of its five medicines used in psychotic disorders.

OBJECTIVES

To determine chlorpromazine dose response and dose side-effect relationships for schizophrenia and schizophrenia-like psychoses.

SEARCH METHODS

We searched the Cochrane Schizophrenia Group's Study-Based Register of Trials (December 2008; 2 October 2014; 19 December 2016).

SELECTION CRITERIA

All relevant randomised controlled trials (RCTs) comparing low doses of chlorpromazine (≤ 400 mg/day), medium dose (401 mg/day to 800 mg/day) or higher doses (> 800 mg/day) for people with schizophrenia, and which reported clinical outcomes.

DATA COLLECTION AND ANALYSIS

We included studies meeting review criteria and providing useable data. Review authors extracted data independently. For dichotomous data, we calculated fixed-effect risk ratios (RR) and their 95% confidence intervals (CIs). For continuous data, we calculated mean differences (MD) and their 95% CIs based on a fixed-effect model. We assessed risk of bias for included studies and graded trial quality using GRADE (Grading of Recommendations Assessment, Development and Evaluation).

MAIN RESULTS

As a result of searches undertaken in 2014, we found one new study and in 2016 more data for already included studies. Five relevant studies with 1132 participants (585 are relevant to this review) are now included. All are hospital-based trials and, despite over 60 years of chlorpromazine use, have durations of less than six months and all are at least at moderate risk of bias. We found only data on low-dose (≤ 400 mg/day) versus medium-dose chlorpromazine (401 mg/day to 800 mg/day) and low-dose versus high-dose chlorpromazine (> 800 mg/day).When low-dose chlorpromazine (≤ 400 mg/day) was compared to medium-dose chlorpromazine (401 mg/day to 800 mg/day), there was no clear benefit of one dose over the other for both global and mental state outcomes (low-quality and very low-quality evidence). There was also no clear evidence for people in one dosage group being more likely to leave the study early, over the other dosage group (moderate-quality evidence). Similar numbers of participants from each group experienced agitation and restlessness (very low-quality evidence). However, significantly more people in the medium-dose group (401 mg/day to 800 mg/day) experienced extrapyramidal symptoms in the short term (2 RCTS, n = 108, RR 0.47, 95% CI 0.30 to 0.74, moderate-quality evidence). No data for death were available.When low-dose chlorpromazine (≤ 400 mg/day) was compared to high-dose chlorpromazine (> 800 mg/day), data from one study with 416 patients were available. Clear evidence of a benefit of the high dose was found with regards to global state. The low-dose group had significantly fewer people improving (RR 1.13, 95% CI 1.01 to 1.25, moderate-quality evidence). There was also a marked difference between the number of people leaving the study from each group for any reason, with significantly more people leaving from the high-dose group (RR 0.60, 95% CI 0.40 to 0.89, moderate-quality evidence). More people in the low-dose group had to leave the study due to deterioration in behaviour (RR 2.70, 95% CI 1.34 to 5.44, low-quality evidence). There was clear evidence of a greater risk of people experiencing extrapyramidal symptoms in general in the high-dose group (RR 0.43, 95% CI 0.32 to 0.59, moderate-quality evidence). One death was reported in the high-dose group yet no effect was shown between the two dosage groups (RR 0.33, 95% CI 0.01 to 8.14, moderate-quality evidence). No data for mental state were available.

AUTHORS' CONCLUSIONS

The dosage of chlorpromazine has changed drastically over the past 50 years with lower doses now being the preferred of choice. However, this change was gradual and arose not due to trial-based evidence, but due to clinical experience and consensus. Chlorpromazine is one of the most widely used antipsychotic drugs yet appropriate use of lower levels has come about after many years of trial and error with much higher doses. In the absence of high-grade evaluative studies, clinicians have had no alternative but to learn from experience. However, such an approach can lack scientific rigor and does not allow for proper dissemination of information that would assist clinicians find the optimum treatment dosage for their patients. In the future, data for recently released medication should be available from high-quality trials and studies to provide optimum treatment to patients in the shortest amount of time.

Chlorpromazine dose for people with schizophrenia

BACKGROUND

Chlorpromazine is one of the three antipsychotic drugs on the WHO Essential Drug List. It is used worldwide. The optimal dose has been the subject of evaluative research but summaries of this work are rare.

OBJECTIVES

To determine chlorpromazine dose response and dose adverse effect relationships for schizophrenia and schizophrenia-like psychoses.

SEARCH STRATEGY

We searched the Cochrane Schizophrenia Group Trials Register (December 2008). References of all included studies were examined for further trials.

SELECTION CRITERIA

All relevant randomised controlled trials (RCTs) comparing fixed doses of chlorpromazine for people with schizophrenia and reporting clinical outcomes.

DATA COLLECTION AND ANALYSIS

We extracted data independently. For dichotomous data we calculated fixed-effect relative risk (RR) and their 95% confidence intervals (CI). For continuous data, we calculated weighted mean differences (WMD) based on a fixed-effect model.

MAIN RESULTS

We included four relevant studies (1012 participants) in this review. They are all hospital-based trials, have a duration of less than six months and are at moderate risk of bias. When low dose (</=400mg/day) was compared with medium dose (401-800 mg/day) mental state data were very few and difficult to interpret (n=22, 1 RCT, WMD 'withdrawal retardation' -2.00 CI -3.76 to -0.24). More people left for inefficacy of treatment in the low dose group (n=48, 1 RCT, RR 4.24 CI 0.24 to 74.01). In the short term, all measured extrapyramidal adverse effects tended to be lower in the low dose group (n=70, 2 RCTs, RR dystonia 0.20 CI 0.04 to 0.97). When low dose was compared with high (>800mg/day) data were taken from only one study (2gms chlorpromazine/day). Global state outcomes tended to favour the high dose group (n=416, 1 RCT, RR 'No clinically important improvement 1.12 CI 1.01 to 1.23). One case of death was reported in the high dose group (n=416, RR 0.33 CI 0.01 to 8.14) and a significantly greater number of people in the high dose group left early due to disabling adverse effects (n=416, RR 0.10 CI 0.04 to 0.27). Significantly less dystonia and unspecified extrapyramidal adverse effects were reported in the low dose group (n=416, dystonia RR 0.11 CI 0.02 to 0.45, unspecified extrapyramidal adverse effects RR 0.43 CI 0.32 to 0.59). People in both groups experienced akathisia (n=416, RR1.00 CI 0.55 to 1.83).

AUTHORS' CONCLUSIONS

The average dose of chlorpromazine given to people with schizophrenia has declined across time, but this has come about by long - and sometimes hard - experience rather than from direction from high-grade trial-based evidence. This progression towards gentler levels of dosing has taken six decades. We hope that, for modern compounds, data from relevant high-grade evaluative studies will be much more swiftly available to guide informed practice.

Associations between side effects of nemonapride and plasma concentrations of the drug and prolactin

Associations between neuroleptic side effects and plasma concentrations of the drug and prolactin were investigated in 33 acutely exacerbated schizophrenic patients (16 males and 17 females) treated with a fixed dose of nemonapride (18 mg/day), a new substituted benzamide, for 3 weeks. The most frequently observed side effects during nemonapride treatment were extrapyramidal symptoms such as akathisia (69.7%), dystonia (48.5%), hypokinesia (45.5%), tremor (39.4%) and increased salivation (36.4%). There were positive correlations between prolactin response and extrapyramidal side effects (EPS) scores after 1 week (Spearman rank correlation rs=.651, P<.01), 2 weeks (rs=.567, P<.05) and 3 weeks (rs=.670, P<.01) in male patients although no significant correlations were found in female or total patients. No significant correlations were found between plasma concentrations of the drug and total or any subscale side effects scores. The present study thus suggests that the spectrum of nemonapride-induced side effects is characterized by predominant extrapyramidal symptoms, and that prolactin response as an index of dopamine blockade reflects severity of EPS at least in male patients treated with nemonapride.

Chlorpromazine-induced inhibition of catecholamine secretion by a differential blockade of nicotinic receptors and L-type Ca2+ channels in rat pheochromocytoma cells

We investigated the effect of chlorpromazine (CPZ), a phenothiazine neuroleptic, on catecholamine secretion in rat pheochromocytoma (PC12) cells. CPZ inhibited [3H]norepinephrine ([3H]NE) secretion induced by 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP), an agonist of nicotinic acetylcholine receptors (nAChRs) with an IC50 value of 1.0 +/- 0.2 microM. The DMPP-induced rise in cytosolic free Ca2+ concentration [Ca2+]i was inhibited by CPZ with an IC50 of 1.9 +/- 0.1 microM. The DMPP-induced increase in cytosolic free Na+ concentration [Na+]i was also inhibited by CPZ with a similar potency. Furthermore, the binding of [3H]nicotine to PC12 cells was inhibited by CPZ with an IC50 value of 2.7 +/- 0.6 microM, suggesting that the nAChRs themselves are inhibited by CPZ. In addition, both 70 mM K+-induced [3H]NE secretion and [Ca2+]i increase were inhibited by CPZ with IC50 of 7.9 +/- 1.1 and 6.2 +/- 0.3 microM, respectively. Experiments with Ca2+ channel antagonists suggest that L-type Ca2+ channels are mainly responsible for the inhibition. We conclude that CPZ inhibits catecholamine secretion by blocking nAChRs and L-type Ca2+ channels, with the former being more sensitive to CPZ.

The use of a side effect as a qualitative indicator of plasma chlorpromazine levels

Chlorpromazine (CPZ) is widely used in South African hospitals. The purpose of this study was to determine whether any physiological parameter (side-effect) could be correlated with plasma concentrations of CPZ or its metabolites. In the absence of a blood level, such a correlation could serve as a qualitative indicator of the amount of chlorpromazine in the body. Such a marker can assist the psychiatrist with therapeutic decisions regarding poor compliance and the lack of response with the drug. Fifteen schizophrenic patients were included in this study and regression analysis was used to determine any correlation between CPZ, 7-hydroxychlorpromazine, Chlorpromazine-N-oxide, Nor1 chlorpromazine, Nor2 chlorpromazine, chlorpromazine sulfoxide, Nor2 chlorpromazine sulfoxide and blood pressure, pulse rate, sedation and finger tremor. No correlation was seen between blood pressure or pulse rate and plasma concentrations of CPZ or the metabolites. A good correlation was seen between sedation, 7- hydroxychlorpromazine (P=0.035) and chlorpromazine sulfoxide (P=0.016). The results suggest that as the levels of chlorpromazine sulfoxide increase, the probability of sedation increases, while increasing levels of 7-hydroxychlorpromazine have the opposite effect. A good correlation was also seen between finger tremor and chlorpromazine levels (P=0.035). These results suggest that there is a 50% probability that the patient would experience finger tremor when the plasma concentration of chlorpromazine is 46 ng/ml. This study demonstrated the potential for the use of sedation and finger tremor as qualitative indicators of the plasma concentration of CPZ and two metabolites. Further studies with larger patient numbers are warranted.

The relationship between serum concentration and therapeutic effect of haloperidol in patients with acute schizophrenia

Haloperidol is the most commonly used antipsychotic drug in the therapy of acute schizophrenia. Clinicians have been using therapeutic drug monitoring in an attempt to improve clinical application of this drug. The scale of interest in this area is emphasised by the large number of studies (about 50) concerning the serum concentration-therapeutic effect relationship (SCTER) of haloperidol, including 35 studies on patients with acute schizophrenia. However, conflicting results concerning the existence and position of a therapeutic window have emerged. This article aims to provide a comprehensive review of the study design of studies in patients with acute schizophrenia before the study data are used for decision-making. For this purpose, a reproducible system for the evaluation of studies in this special area, a so-called total study score (TSS), was developed on an empirical basis. Thus, insufficient study design was found to be a reason for negative results. On the other hand, in spite of a great variability, the majority of studies with good design provided evidence for a significant SCTER: a bisigmoidal dependence of clinical effect on haloperidol serum concentration. The therapeutic effects of haloperidol increase at low concentrations, and the concentration has a maximum effect at about 10 micrograms/L and again decreasing at higher concentrations. The data of 552 patients also fit to this model in a single scatter plot (pseudo-r2 = 0.076, p < 0.001). The position of the therapeutic window was determined at about 5.6 to 16.9 micrograms/L. Patients treated with serum concentrations within this optimal range had a significantly better response compared with outside this range (p < 0.001, Student t-test). Therefore, a quantitative synthesis of all available data by means of effect-size analysis provides a mean effect-size (g) = 0.499 +/- 0.182 (standard deviation) for the comparison of haloperidol-treatment with serum concentrations within versus outside the therapeutic window. Thus, because of this moderate positive effect, serum concentration assay of haloperidol is recommended for patients with acute schizophrenia in a therapeutic drug monitoring programme. The modalities of haloperidol therapeutic drug monitoring in clinical practice are discussed, e.g. patient selection, method and time for serum concentration measurement, influence of premedication and comedication, interpretation of results and dose adjustment. Clinical investigations into this subject should focus on covariates which are responsible for the variability of the SCTER. Serum concentration assay is advised for investigations of nonresponse to exclude patients with pseudo-drug resistance.

Dose-response relationships for the antipsychotic effects and Parkinsonian side-effects of typical neuroleptic drugs: practical and theoretical implications

1. From a review of published literature it is concluded that the minimum dose of a neuroleptic drug (NLD) required to alleviate psychosis is very similar to that producing minimal parkinsonian side effects (PSE). This conclusion is reached both from group comparisons and individual comparisons of dose/response relations (DRR) for the two effects. 2. A lower dose of NLD is usually sufficient to prevent relapse in well stabilized patients than is needed to check an active psychotic state. 3. Anticholinergic agents used to reduce side effects of typical NLD can retard the therapeutic process during neuroleptic treatment of acute psychosis. Although it is not fully established that this is a central interaction, it is consistent with the idea that minimal side effects are a necessary condition for therapeutic effectiveness with typical antipsychotic drugs. 4. In relapse-free maintenance of psychosis-prone patients, tolerance occurs to PSE. Thus few patients need experience prolonged side effects during maintenance treatment with neuroleptics. 5. The evidence reviewed is discussed with respect to a previous hypothesis of the supposedly "indirect" action of typical neuroleptic drugs in therapy for psychosis. The evidence is consistent with the idea of a close causal relation between minimal PSE of these drugs, and their therapeutic effectiveness in the acute stage of treatment.

Neuroleptic dose and schizophrenic symptoms. A survey of prescribing practices

A study was conducted to survey the prescribing practices of neuroleptic doses in 100 consecutively hospitalized DSM-III-R schizophrenic patients. The relationship between doses and clinical and symptomatological variables was subsequently analyzed. Patients were evaluated through the Positive and Negative Syndrome Scale (PANSS). The peak mean dose in chlorpromazine equivalents was 1290 (range 250-7200). Haloperidol was the most commonly employed neuroleptic (67 patients). Neuroleptic doses were correlated with excitement, suspiciousness, hostility, uncooperativeness and poor impulse control. The neuroleptic doses administered in our hospital were similar to those found in other survey reports but higher than those recommended by the controlled dose-response studies. The correlation found between neuroleptic doses and symptoms of disruptive behavior suggests that we employed high-dose practices to treat the disruptive symptoms of schizophrenia. We concluded that it is useful to distinguish between the neuroleptic doses required to control the psychotic episode and those to treat the disruptive behavior.

Smoking and body weight influence the clearance of chlorpromazine

The population pharmacokinetic parameters of chlorpromazine (CPZ) in chronic schizophrenic patients were evaluated using 189 plasma concentration measurements from 31 patients. A NONMEM analysis demonstrated that the clearance of CPZ depended on the patient's body weight. Cigarette smoking and cannabis smoking increased the clearance of CPZ. Chronic alcohol consumption and the concurrent use of anticholinergics did not appear to influence the clearance of CPZ significantly.

Clinical pharmacokinetics of antipsychotics

The antipsychotics are a chemically diverse group of heterocyclic compounds, which ameliorate many symptoms of schizophrenia. Most of the antipsychotics are very lipophilic and cross lipoidal membranes freely. When administered orally, they are well absorbed and undergo substantial pre-systemic elimination (bioavailability: 10-70%), are highly bound to plasma proteins (75-99%) and tissues, and are extensively distributed (VD: 100-1000 L). Primary route of elimination for most of antipsychotics is hepatic metabolism and biotransformation produces active metabolites. There is no linear relationship between the concentration of parent compound and different metabolites, and clinical relevance of pharmacologically active metabolites is not well understood. There are wide interindividual variabilities in pharmacokinetics, which result in large differences in steady-state plasma concentrations on the same dose regimen. The existence of optimal therapeutic ranges for most antipsychotics remains controversial. One of the major problems is the lack of well-designed studies that involve sufficient numbers of patients to clearly establish a therapeutic range for these drugs and is further complicated by the presence of a large number of pharmacologically active metabolites. However, the pronounced interindividual kinetic variabilities, combined with problems of noncompliance and drug interactions, and the delayed onset of clinical response in relation to initiation of treatment with antipsychotics are reasons why drug monitoring in conjunction with clinical status of the patient can be useful. Indications for antipsychotic drug monitoring include lack of response, non-compliance, toxicity, and drug interactions when other drugs are coadministered.

A multidimensional (pharmacokinetic and clinical-biological) approach to neuroleptic response in schizophrenia. With particular reference to drug resistance

Despite the undisputable effectiveness of the available neuroleptic medications (NDs), short and long term outcome of schizophrenic disorders is often unsatisfactory and drug resistance phenomena are not uncommon. The causes of variability in the response seem to be primarily due to the heterogeneity of schizophrenic syndromes in terms of clinical history, symptoms, and biological patterns. The high non-compliance rate is an important source of therapeutic failure particularly during long-term treatment. The lacking or poor response to NDs can be linked to peculiar drug disposition patterns, which lead generally to inadequate plasma concentrations (too low or too high). To deal with pharmacokinetic aspects two main topics are discussed in this paper: (A) the interindividual differences in bioavailability and metabolism and (B) the plasma level-clinical response relationship. The knowledge of these aspects can significantly contribute to reducing some pseudo-drug resistance phenomena. Moreover, the need to combine these data with the new acquisitions on the pathophysiology of these disorders is emphasized, to deal properly with the complexity of drug response mechanisms during therapy with NDs. New heuristic paradigms for schizophrenic disorders, stemming from the evidences of their heterogeneity, in terms of clinical course, outcome and biological findings, should be considered in relation to response. Accordingly, the concept of 'therapeutic window' (as conceived in the '70s) for NDs (as for antidepressants) needs to be reexamined in relation to recent clinical, neurochemical and neuromorphological data. Finally, the indications for NDs monitoring (particularly for drugs like haloperidol and fluphenazine) are reported, suggesting that a multidimensional operational strategy could be particularly suitable to deal with drug resistance problems.

Timing of acute clinical response to fluphenazine

The time course of clinical improvement was studied in 41 schizophrenic and schizoaffective acute in-patients treated for 28 days with 10, 20 or 30 mg/day of oral fluphenazine hydrochloride in a double-blind, randomised study. Significant improvement was seen in the four BPRS factors: thinking disturbance, hostile-suspiciousness, withdrawal-retardation and anxious depression. The first two of these factors were improved by day 5. Significant improvement was seen up to day 22 for three of the four factors, but without significant improvement during the last week (although scores continued to drop). The half of the sample showing greater overall improvement did not improve faster than the sample as a whole. These more improved subjects did not differ significantly from the less improved subjects in the thinking disturbance factor until day 15, suggesting that at least a two-week neuroleptic trial would be necessary to begin to differentiate more and less responsive patients. The longer-term course of improvement cannot be determined from these data. The withdrawal-retardation and anxious depression factors showed their greatest improvement later than the 'positive' symptom factors, suggesting that the former may improve as a result of change in the latter.

Time course of D2-dopamine receptor occupancy examined by PET after single oral doses of haloperidol

Central D2-dopamine receptor occupancy was followed by repeated PET experiments after administration of single oral doses of haloperidol to four healthy men. D2-dopamine receptor occupancy was high already 3 h after administration of 4 and 7.5 mg haloperidol and remained high for at least 27 h. Akathisia appeared when D2-dopamine receptor occupancy was maximal. After initiation of neuroleptic drug treatment several days or weeks may elapse before antipsychotic effect is evident. The results of this study do not indicate that any late onset of the antipsychotic effect is related to an insufficient D2-dopamine receptor occupancy during the first days of treatment.

Calcium antagonists fail to protect mammalian spinal neurons after physical injury

Most investigations of calcium antagonists as treatments for experimental spinal cord injury (SCI) have not demonstrated significant reduction of tissue damage or improvement in neurologic outcome. Many of these studies were prompted by reports that these agents increase blood flow to ischemic tissues. However, in vitro studies of renal and neuronal tissues subjected to an anoxic stress have shown that the calcium antagonists can confer direct protection on stressed parenchymal cells. We have used a tissue culture model of nerve cell injury to investigate whether calcium antagonists increase the probability of survival of spinal cord neurons after a defined physical trauma. Preliminary toxicity studies determined the maximum nontoxic dosages of verapamil (80 microM), nifedipine (10 microM), and chlorpromazine (10 microM) for neurons in our cultures. Preselected neurons (100-200 per study) were subjected to amputation of one primary dendrite at a distance of 100 microns from the perikaryon. Erythrosine B tests of viability conducted 24 h after lesioning failed to demonstrate that neurons injured in the presence of any one of these agents had an increased probability of survival compared to operated control neurons. Viability evaluations conducted 2 h after injury with phase contrast microscopy showed no evidence of slowed deterioration. Correction for other lesion physical parameters (lesion diameter and the extent of proximal segment retraction) also failed to reveal any increased protection by these agents. We conclude that calcium antagonists alone will not be useful for treatment of the primary injury of SCI.

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.

Plasma levels of fluphenazine decanoate. Effects of site of injection, massage and muscle activity

Depot neuroleptics are now commonly used for maintenance therapy of schizophrenia. Their physicochemical composition makes them ideal for such use because they are long-acting and show stable blood levels for prolonged periods. Their absorption from the site of injection may, however, be affected by local muscle factors. This paper describes three such factors in relation to fluphenazine decanoate: varying the site of injection; massage of the injection site; and effects of muscular exercise. Our results suggest that fluphenazine pharmacokinetics are not significantly affected by any of these factors.

Neuroleptic plasma concentrations and clinical response: in search of a therapeutic window

There is much interest in finding a therapeutic window for commonly used neuroleptics so that dosage can be individualized and side effects minimized. The authors review specific requirements of good study design and survey the literature that has investigated the relationship between therapeutic response and plasma concentrations of neuroleptics. The evidence from a number of fixed-dose haloperidol studies suggests, but does not yet prove, the existence of a therapeutic window for this compound.

Chlorpromazine protects brain tissue in hypoxia by delaying spreading depression-mediated calcium influx

We have investigated the possible protective effect of chlorpromazine in hypoxia of brain tissue, using rat hippocampal slices maintained at 35-36 degrees C. The recovery of synaptic transmission along the Schaffer collaterals to the CA1 pathway after 9 min hypoxia was compared in chlorpromazine-treated and in control slices. Recovery upon reoxygenation was the exception in control slices, while it was observed in approximately 50 and 100% of slices treated with 7 and 70 microM chlorpromazine, respectively. Chlorpromazine also significantly delayed the occurrence of the hypoxia-induced spreading depression (SD). Recovery took place when SD occurred late during hypoxia, not when it occurred early. In those slices in which 7 microM chlorpromazine afforded no protection, SD occurred as early as it did in control slices. In further experiments, we deliberately induced SD during hypoxia in 70 microM-treated slices by topically applying a drop of high-K+ artificial cerebrospinal fluid (ACSF). Recovery was not observed when SD was induced early, but it was observed when it was induced near the end of the hypoxic period. Slices exposed to the same period of hypoxia in Ca2+-free ACSF recovered synaptic transmission (even without chlorpromazine treatment) despite early induction of SD. We conclude that: chlorpromazine protects brain tissue from hypoxia-induced irreversible loss of synaptic transmission; it does so by delaying the occurrence of SD, and hence shortening the time spent in the SD-induced depolarized state; and the harm done by SD in hypoxia is related to the influx of Ca2+ into neurons.

Pharmacokinetics and therapeutic efficacy of haloperidol decanoate after loading dose administration

For this open study, we selected 21 chronic psychotic female in-patients (16 of them schizophrenics) who were being maintained on oral neuroleptics. After a wash-out period, they were treated by intramuscular depot injections of haloperidol decanoate, once a month for four months. The dose was calculated from the previous oral dosage, and the amount of the first injection was double that of the three following injections. Relatively stable plasma levels of haloperidol were achieved with the first injection, and corresponded to those observed with oral medication. A very significant correlation was found between plasma level and the dose administered, but not between plasma level and therapeutic effect. The clinical condition of about two-thirds of the patients remained unchanged or improved, compared with the period of oral treatment. During the first two months of treatment, there was more rigidity and tremor, but from the third month, the extrapyramidal symptoms were less pronounced than during the period of oral neuroleptics.

Neuroleptic blood levels and clinical response

Gas chromatography and radioreceptor assay technologies made possible the measurement of nanogram quantities of neuroleptic in the blood. They revealed large differences in blood concentrations among patients receiving the same oral dose. This led to the hope that measuring neuroleptic concentrations would allow more effective oral dosing for individual psychotic patients. Early attempts to study neuroleptic concentration/clinical response patterns, using chlorpromazine, produced confusing results. Many of the studies had serious design flaws, and were complicated by the many active metabolites of chlorpromazine. Adequate blood level/response studies should use fixed drug dosage schedules, drug-responsive patients, and neuroleptics without active metabolites. Brain concentration of drug is probably better reflected by erythrocyte than by plasma concentration. Therefore, recent investigators have usually used erythrocyte haloperidol or butaperazine concentrations to study level/response relationships. These recent studies strongly suggest an "optimal concentration" level/response pattern for haloperidol and butaperazine. Patients tend to respond best to moderate concentrations of neuroleptic, and nonresponse can be due to either too low or too high concentrations. In the latter case, decreasing the oral dose should be seriously considered. Blood level findings remain preliminary. The clinician should continue to fine-tune his clinical skills, using neuroleptic blood concentrations to complement his clinical judgment, in the attempt to determine the lowest effective dose for the individual patient.

Plasma level monitoring of antipsychotic drugs. Clinical utility

The steady-state plasma concentrations of antipsychotic drugs show large interpatient variations but remain relatively stable from day to day in each individual patient. Monitoring of antipsychotic drug concentrations in plasma might be of value provided the patients are treated with only 1 antipsychotic drug. Some studies have reported a relationship between therapeutic response and serum antipsychotic drug 'concentrations' as measured using the radioreceptor assay (RRA) method, which measures dopamine receptor-blocking activity in plasma. Most studies, however, have failed to demonstrate such a relationship, and the RRA does not seem to provide the generally useful tool for plasma concentration monitoring of antipsychotic drugs that was hoped for initially. A lack of correlation between dopamine receptor-blocking activity in plasma and therapeutic response may be due to differences in the blood-brain distribution of both antipsychotic drugs and their active metabolites. Chemical assay methods (e.g. GLC and HPLC) have been used in studies which examined the relationships between therapeutic response and antipsychotic drug concentrations in red blood cells and in plasma. It seems that for these drugs, measuring red blood cell concentrations does not offer any significant advantage over measuring plasma concentrations. Reasonably controlled studies of plasma concentration-response relationships using randomly allocated, fixed dosages of chlorpromazine, fluphenazine, haloperidol, perphenazine, sulpiride, thioridazine and thiothixene have been published but often involve relatively few patients. A correlation between therapeutic response and plasma concentrations of thioridazine and its metabolites has not been demonstrated, and plasma level monitoring of thioridazine and its metabolites therefore appears to have no clinical value. Clinical behavioural deterioration concomitant with high plasma concentrations of chlorpromazine and haloperidol have been reported. A dosage reduction might be considered after 2 to 4 weeks' treatment in non-responders who have plasma chlorpromazine concentrations above 100 to 150 micrograms/L or plasma haloperidol concentrations above 20 to 30 micrograms/L. Non-responders and good responders to chlorpromazine treatment, however, have plasma drug concentrations in the same range, and a therapeutic range of plasma chlorpromazine levels has not been defined. Therapeutic plasma haloperidol concentrations (i.e. 'window') in the range of 5 to 20 micrograms/L have been reported by some investigators, but others have found no such relationship.(ABSTRACT TRUNCATED AT 400 WORDS)

Prediction of treatment response in schizophrenia: clinical use of neuroleptic blood levels

The relationship between clinical response and plasma neuroleptic levels in schizophrenia is unclear. Apart from the inadequacy of the plasma neuroleptic assay method, resistance to neuroleptic treatment in some schizophrenics presents a serious problem in studies looking into the plasma drug level versus clinical response correlation. Previous studies have suggested a very wide range of plasma neuroleptic levels in responders. At present, plasma neuroleptic level does not predict clinical response in schizophrenics in general, but may have application in special situations such as suspected drug toxicity, neuroleptic resistance or idiosyncratic response to neuroleptic drugs.

Effects of sulpiride and chlorpromazine on autistic and positive psychotic symptoms in schizophrenic patients--relationship to drug concentrations

Schizophrenic patients were treated with fixed doses of sulpiride (800 mg/day) or chlorpromazine (CPZ) (400 mg/day) during a period of 8 weeks using a double-blind design. There were 25 patients in each group and all of them fulfilled the Research Diagnostic Criteria (RDC) for schizophrenia. Autistic and psychotic symptoms were rated with subscales developed from the Comprehensive Psychopathological Rating Scale (CPRS). Autistic symptoms were also rated with a subscale of the Nurse's Observation Scale for Inpatient Evaluation (NOSIE). Sulpiride was superior to CPZ in reducing the autistic symptoms. Patients with low concentrations of sulpiride in serum had a better recovery rate from autistic symptoms than those with high concentrations. Both drugs reduced positive psychotic symptoms to the same degree.

Haloperidol plasma levels and clinical response in paranoid schizophrenics

The relationship between haloperidol plasma levels, plasma prolactin, and therapeutic efficacy was evaluated in 20 paranoïd schizophrenics in a fixed-dose study for 6 weeks. We found a significant intrapatient cross-correlation of therapeutic efficacy, as measured by decrease in MSS and BPRS rating scales and time-dependent haloperidol and prolactin changes, which were tested at weekly intervals. However, no significant curvilinear relationship was present between steady-state haloperidol plasma levels and MSS and BPRS improvement scores. Our data do not furnish clear-cut evidence in favor of the existence of a therapeutic window for haloperidol plasma levels in paranoïd schizophrenia.

Total and free plasma neuroleptic levels in schizophrenic patients

Nineteen male patients, under 35 years of age, newly admitted with a diagnosis of schizophrenia, were treated with either chlorpromazine or haloperidol at a fixed dosage for 25 days. Both total and free plasma neuroleptic levels were measured using a radioreceptor assay. Clinical response was measured by the Brief Psychiatric Rating Scale (BPRS). On day 25, nonresponders (those with a decrease of less than 8 points on the BPRS) had both total and free plasma neuroleptic levels within the range observed in responders. It is therefore concluded that lack of therapeutic response is generally not due to inadequate plasma drug levels.

Relationships between drug concentrations in serum and CSF, clinical effects and monoaminergic variables in schizophrenic patients treated with sulpiride or chlorpromazine

Schizophrenic patients were treated with fixed doses of sulpiride (800 mg) or chlorpromazine (400 mg) during eight weeks using a double-blind design. In order to examine relationships between pharmacokinetic, clinical and biochemical parameters in relation to treatment the following variables were recorded before and 1, 2, 4 and 8 weeks after treatment. Concentrations of sulpiride, CPZ, 7-OH-CPZ, nor1-CPZ were determined in serum and CSF using liquid chromatography and mass fragmentography. Clinical variables were psychotic morbidity and side effects as evaluated by CPRS, NOSIE and side effect ratings. Monoaminergic variables were concentrations of the major cerebral monoamine metabolites, HVA, 5-HIAA and MOPEG in the cerebrospinal fluid as measured by mass fragmentography. Prolactin levels in serum and CSF were measured by radioimmunoassay. During steady state, concentrations of sulpiride in serum varied fourfold between patients and CPZ twentyfold. Drug concentrations in serum and CSF were highly correlated in CPZ-but not in sulpiride-treated patients. Although sulpiride passed into the CSF, transport between serum and CSF was restricted. In the sulpiride group, improvement of psychotic morbidity and HVA elevation in CSF tended to be negatively related to the drug concentrations in serum. Sulpiride-treated patients with extrapyramidal side effects had significantly higher drug concentrations in serum. In CPZ-treated patients, improvement of psychotic morbidity, HVA elevation and prolactin elevation all tended to be positively correlated to drug concentrations in serum and CSF. CPZ-treated patients with extrapyramidal side effects also had significantly higher CPZ concentrations in serum. In both treatment groups, the MOPEG reduction in CSF tended to be correlated to improvement of psychotic morbidity. The study supplied clinical evidence for the view that antipsychotic drugs belonging to the phenothiazine and benzamide series induce antipsychotic effects in schizophrenic patients in a graded fashion which is proportional to the degree of interaction with the central dopaminergic mechanisms. The results also support the view that sulpiride has a more selective effect on central dopaminergic mechanisms than chlorpromazine. In the schizophrenic patients studied and with the doses used, sulpiride concentrations tended to be maximal with regard to clinical and biochemical effects. For CPZ on the other hand, drug concentrations in some patients seemed to be too low to induce optimal effects.

Clinical evaluation of sulpiride in schizophrenic patients--a double-blind comparison with chlorpromazine

To evaluate the clinical potential of sulpiride for the treatment of schizophrenic patients, a double-blind study was performed comparing fixed doses of sulpiride (800 mg daily) and chlorpromazine (400 mg daily). Twenty-five schizophrenic (RDC) patients participated in each treatment group. Antipsychotic effects were evaluated by CPRS and NOSIE ratings before and after 1, 2, 4 and 8 weeks of treatment. Interrater reliabilities for CPRS items and subscales were satisfactory. Treatment with sulpiride or chlorpromazine resulted in a significant reduction of psychotic morbidity as estimated by CPRS and global ratings. CPRS scores reflecting autism were significantly reduced in all ratings of sulpiride-treated patients, but only after four weeks in the chlorpromazine group. Total NOSIE scores indicated improvement in both treatment groups. A significant difference in favour of sulpiride was obtained for the NOSIE subscale "retardation". Extrapyramidal side effects occurred at a similar frequency in both treatment groups. Autonomic side effects occurred to a greater extent in chlorpromazine-treated patients. Lactation was reported only in four sulpiride-treated patients. Liver transaminase enzymes in serum were markedly elevated only in chlorpromazine-treated patients. The results indicate that sulpiride has a marked antipsychotic effect which is at least not inferior to that of chlorpromazine. A better effect on autistic components of behaviour was demonstrated for sulpiride. The results indicate a higher risk of lactation but a lower risk of anticholinergic side effects and liver toxicity for treatment with sulpiride than with chlorpromazine.

Influence of hemodialysis on monoamine oxidase kinetics in platelets from chronic schizophrenic patients

Platelet monoamine oxidase (MAO) activity in seven chronic schizophrenic patients undergoing hemodialysis treatment was studied. The treatment was performed in a double-blind crossover design. A significant increase in MAO activity was observed after 5 h of active dialysis, whereas inactive dialysis did not significantly alter the enzyme activity. The increase in MAO activity could be explained by the observed significant decrease in apparent Km values for the amine (phenethylamine) studied. During a treatment period of 8 weeks, the MAO activity was not significantly altered with either active or sham dialysis. No relation between clinical ratings and platelet MAO activity was observed. Plasma from the seven patients was collected before and after 5 h of active or inactive dialysis and incubated with rat brain mitochondrial MAO (RBM-MAO). No difference was noted in the RBM-MAO-activity-regulating properties of the plasma sampled during either sham or active dialysis.

Hemodialysis in the treatment of chronic schizophrenic patients: a double-blind crossover study

In order to examine the reported beneficial effects of hemodialysis in chronic schizophrenic patients, a double-blind crossover study was carried out. Of the 47 patients considered for treatment, 10 diagnosed as chronic schizophrenics according to the Feighner and DSM-III criteria were accepted to the study. Seven of these patients completed the full program, four of whom belonged to a large family with a high incidence of schizophrenia. All patients were on antipsychotic medication throughout the study. Psychopathological evaluations were performed regularly in a blind fashion using the Comprehensive Psychopathological Rating Scale (CPRS) and the Nurse Observation Scale for Inpatient Evaluation (NOSIE-30). Samples of blood, urine, cerebrospinal fluid, and dialysate were obtained for examination. Three patients improved during active dialysis and two patients improved during sham treatment. Improvement in the five patients took place during the first treatment period. This study failed to demonstrate a therapeutic effect of hemodialysis superior to the sham procedures.

Serum neuroleptic and prolactin levels in schizophrenic patients and clinical response

Following a drug-free placebo period lasting at least 1 week, 10 female and 11 male newly hospitalized schizophrenic patients received chlorpromazine (CPZ) 200 mg/day for 1 week and 400 mg/day the following week. Serum CPZ equivalent (CPZ-E) levels were measured at the end of each week of CPZ treatment with a radioreceptor assay. Chlorpromazine-E levels were significantly higher in females than males, but this finding could be accounted for by differences in body weight. Serum prolactin (PRL) levels were also higher in females than males. After differences in serum CPZ-E level were adjusted for, females still had significantly higher serum PRL levels than males. Serum PRL levels increased between the first and second treatment weeks in females but not in males. Correlations between serum CPZ-E and PRL levels were higher among males than females. Significant improvement for the patient group as a whole was observed during the 2 weeks of treatment, with a strong trend for females to improve more than males. Clinical outcome at this initial period was not predicted by either serum PRL levels or serum CPZ-E levels.

The presence of 7-hydroxychlorpromazine in CSF of chloropromazine-treated patients

7-Hydroxychlorpromazine (7-OHCPZ) has been identified and quantified in CSF from chlorpromazine (CPZ)-treated schizophrenic patients. The level of the metabolite in CSF was similar to that of CPZ. In serum the amount of 7-OHCPZ was about 30% of CPZ. The concentration of 7-OHCPZ in csf was positively and significantly correlated to the serum level.

Does a plasma level of chlorpromazine help?

Forty-eight newly admitted schizophrenic patients were treated with a fixed, conservative (6.6 mg/kg) dose of chlorpromazine (CPZ) for 28 days. CPZ plasma levels were measured by a gas chromatography mass spectrometry method (GCMS) using 2H6-chlorpromazine as an internal standard. At the end of the fixed-dose period, "responders" had the same plasma levels as "non-responders", suggesting that lack of response is primarily a matter of the illness' sensitivity to CPZ, not to a plasma level below some therapeutic window. After the fixed-dose period, the dosage of CPZ was increased in the "non-responders" by physician's choice. Improvement occurred over a wide range of 10-225 picomoles (3-72 ng)/ml. Above 300 picomoles (95 ng/ml) 4 inaccessible patients eventually became much worse, suggesting psychotoxicity. It is in the inaccessible patient whose illness is only minimally, or not at all, sensitive to CPZ that a plasma level might be especially useful. Interpretation of plasma levels is complicated by the speed of response: some initial non-responders improved by the 56th day of treatment on very conservative plasma levels.

Psychotic exacerbation with haloperidol

A case illustrating the worsening of a patient's schizophrenic symptoms following haloperidol dosage increases in presented. This case is remarkable in that few cases of psychotic exacerbation with haloperidol dosage increases have been reported in the world literature. The possibility exists that, like certain tricyclic antidepressants, neuroleptic medication may possess a "therapeutic window,". The concept of a therapeutic window and its relationship to the phenomenon of psychotic exacerbation is reviewed. In evaluating this condition, the clinician should consider other causes of psychotic exacerbation, such as akathisia and anticholinergic psychosis.

Effect of a drug holiday on plasma chlorpromazine levels in chronic schizophrenic patients

Low chloropromazine (CPZ) levels have been measured in chronically treated schizophrenics. We tested six such patients to determine whether a 2-week CPZ-free period (drug holiday) would improve plasma CPZ levels. We also monitored psychiatric symptoms, autonomic function, and extrapyramidal signs. We found these patients to have low predose CPZ levels that did not change appreciably after the drug holiday. Peak levels following the holiday averaged 28 +/- 7 ng/ml higher than those measured prior to the holiday. Drug holidays are safe and should be examined more thoroughly as a means of improving plasma neuroleptic levels in chronically treated schizophrenics.

Concentrations of chlorpromazine and two of its active metabolites in plasma and cerebrospinal fluid of psychotic patients treated with fixed drug doses

Efforts to find a correlation between serum levels of chlorpromazine (CPZ) and clinical effect have been rather unsuccessful, which could be due to fluctuations of CPZ and CPZ metabolite levels during treatment, the complicated metabolism of CPZ, or to varying degrees of protein binding. Using a mass fragmentographic analysis technique the variations of CPZ and two active metabolites nor1-CPZ and 7-OH-CPZ were studied in ten schizophrenic patients during the day at steady state and after withdrawal. There was a significant correlation between the area under curve (AUC) for CPZ in serum during 24-h treatment and serum concentration at different fixed times of the day. The half-life (T 1/2) for CPZ was found to be 8-33 h. 7-OH-CPZ and nor1-CPZ disappeared at about the same rate as the parent compound. The concentration of both metabolites was less than 10 ng/ml after 36 h. CPZ was administered to 43 schizophrenic patients in one of three fixed doses (200, 400, or 600 mg) according to a double-blind design. Plasma and cerebrospinal fluid (CSF) samples were analysed before and after both 2 and 4 weeks' treatment. The levels of the metabolites were considerably lower as compared to CPZ levels. The same levels were found after 2 and 4 weeks' treatment. There were no sex differences. The levels of CPZ and metabolites presented a weak positive correlation to daily dose but not to dose calculated by mg/kg body weight. Older patients tended to have higher CPZ and metabolite levels. The dose effects were very similar in plasma and CSF and there was a highly significant correlation between CPZ levels in serum and CSF. CSF/plasma ratio for CPZ seems to be an individual factor possibly related to variations in protein-binding in plasma and CSF.

Drug-related and illness-related factors in the outcome of chlorpromazine treatment: testing a model

Patients who presented with acute psychoses and were treated with chlorpromazine were first divided into 2 groups with good (23) and poor (13) outcome. These outcome groups differed little in their initial clinical features and showed no difference in 2 indices of dopamine receptor blockade (extrapyramidal symptoms and plasma prolactin concentrations). The group which improved was then subdivided on the basis of evidence of dopaminergic blockade into 15 who had improved and also showed anti-dopamine effects ('responders') and 8 who had improved but showed no anti-dopamine effects ('remitters'). The remainder were eventually classified as 'resistant' to the effects of the drug. The group of 'remitters' contained no patients with nuclear schizophrenia; the 'responders' were mainly nuclear schizophrenics; and the 'resistant' patients were schizophrenic or schizo-affective. The 3 groups who were defined in this way also differed in their subsequent clinical course. It is suggested that this scheme for dividing patients may be useful in clinical work and could also assist research worker to identify the patients who can most appropriately be studied to determine mechanisms of drug action.

Organic anion and cation transport in vitro by dog choroid plexus: effects of neuroleptics and tricyclic antidepressants

Dog lateral choroid plexus accumulates the cation 14C-emepronium and the divalent anion 125I-iodipamide in vitro. At 10 micron, high potency neuroleptics with a substituted piperazine side chain and also haloperidol depress only the uptake of the cation and even stimulate the uptake of the anion. In contrast, at 1--10 micron, the accumulation of both test substances is inhibited by neuroleptics and tricyclic antidepressants with an aliphatic side chain. Such unspecific effects on seemingly unrelated transport systems at concentrations reached clinically in the CSF might explain some side actions of low potency neuroleptics and antidepressants.