Relationships between drug concentrations in serum and CSF, clinical effects and monoaminergic variables in schizophrenic patients treated with sulpiride or 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, specialised tools are used. Three tools have been proven useful to personalise 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 45 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 optimise treatment effects, minimise side effects and ultimately reduce the global burden of diseases, personalised drug treatment has not yet become the standard of care in psychiatry.

A New Look on an Old Issue: Comprehensive Review of Neurotransmitter Studies in Cerebrospinal Fluid of Patients with Schizophrenia and Antipsychotic Effect on Monoamine's Metabolism

Neurotransmitters metabolism has a key role in the physiopathology of schizophrenia as demonstrated by studies measuring monoamine metabolites in patient’s cerebrospinal fluid (CSF) since the beginning of the antipsychotic use. This comprehensive review aims to understand the anomalies of CSF monoamines in schizophrenia and their correlation with clinical and paraclinical features. We also review the influence of antipsychotic treatment on CSF monoamines and discuss the connection with metabolic and inflammatory processes. Studies comparing CSF homovanillic acid (HVA) levels between patients and controls are miscellaneous, due to the heterogeneity of samples studies. However, low HVA is associated with more positive symptoms and a poorer outcome and negatively correlated with brain ventricle size. Based on humans and animals’ studies, antipsychotic treatments increase HVA during the first week of administration and decrease progressively over the time with a fall-off after withdrawal. 5‐hydroxyindolacetic acetic acid levels do not seem to be different in the patient’s CSF compared to controls. Considering metabolic co-factors of neurotrans-mitters synthesis, there is evidence supporting an increase of kynurenic acid in the CSF of patients with schizophrenia. Few studies explore folate metabolism in CSF. Literature also emphasizes the relationship between folate metabolism, inflammation and monoamine’s metabolism. Those results suggest that the CSF monoamines could be correlated with schizophrenia symptoms and treatment outcome. However, further studies, exploring the role of CSF monoamines as biomarkers of disease severity and response to treatment are needed. They should assess the antipsychotic prescription, inflammatory markers and folate metabolism as potential confounding factors.

Classification of neuroleptic drugs - lack of relationship to effect on negative symptoms in schizophrenia

There is both pharmacological and clinical support for a classification of the schizophrenic syndrome into negative and positive subtypes. For neuroleptics that act upon both types of symptoms, it appears that lower doses are required for treatment of negative than for positive symptoms. Successful drug treatment of negative symptoms may therefore depend upon the choice of a correct dosage for the individual patient. Due to variation in pharamacokinetic parameters, similar doses of a neuroleptic drug may result in different plasma levels in individual patients, especially after oral medication. Pharmacokinetic variations, if not under proper control, may easily disguise a concentration-dependent relationship, such as the effects of a neuroleptic drug upon negative and positive symptoms. In drug treatment of negative symptoms it may therefore be an advantage to individualize the doses as a function of plasma drug level measurements, when available. No general relationship has been demonstrated between the chemical properties or pharmacodynamics of neuroleptic drugs and their potential to act upon negative symptoms. Also, the drugs which have been demonstrated to have an “energizing” effect have widely different pharmacokinetic properties. A chemical or pharmacological classification of neuroleptics therefore does not seem to give any information about their possible efficacy in treating negative symptoms in schizophrenia.

Bioequivalence of a New Oral Levosulpiride Formulation Compared With a Standard One in Healthy Volunteers

BACKGROUND

A monocentric, single-dose, open-label, 2-way, crossover randomized study was conducted by the San Matteo Phase I Clinical Trial Unit and Experimental Therapy (Pavia, Italy) to assess the bioequivalence and the systemic tolerability of a new oral formulation of levosulpiride (tablet 25 mg: test) versus a commercially available formulation on the Italian market (tablet 25 mg: reference).

METHODS

Thirty-five healthy adult volunteers, men (n = 19) and women (n = 16), aged between 18 and 55 years were screened and 32 of them were enrolled in the study. After having signed the written informed consent, each subject received a single oral dose of Test or Reference product with 250 mL of natural mineral water, in fasting conditions, interspersed with a 6-day washout period Blood samples were collected up to 36 hours after drug administration: the drug plasma levels were determined by high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. The pharmacokinetic parameters included peak plasma concentration (Cmax), time corresponding to Cmax (tmax), area under the plasma concentration-time curve from zero to infinity (AUC0-∞) or to the last sampling time assessment (AUC0-36), the elimination rate constant (ke), and the terminal half-life (t1/2). Safety was measured by pre- and post-treatment specific biochemical investigations, physical examination, electrocardiogram, occurrence of adverse events, and any information on patients' withdrawal.

RESULTS

The geometric mean ratio Test/Reference (90% confidence interval) for levosulpiride was 103.0% (95.8-110.8) for AUC0-36, 103.6% (95.9-111.9) for AUC0-∞, and 104.3% (94.9-114.6) for Cmax. ke and t1/2 were 0.07 (SD: 0.02) and 9 hours (8-12) for both the formulations. Clearance (L/h) was 29.6 (±13.5) and 30.7 (±14.2) for the test and the reference product, respectively.

CONCLUSIONS

Because the acceptance criteria required by the drug regulatory agency (European Medicines Agency, EMA) for bioequivalence prescribe limits of 80%-120% for untransformed data and 80%-125% for "ln" transformed data, we can confirm that the 2 formulations are bioequivalent, in terms of the rate and extent of absorption.

Pharmacokinetics of levosulpiride after single and multiple intramuscular administrations in healthy Chinese volunteers

The main purpose of this study was to evaluate the pharmacokinetics of levosulpiride in humans after single and multiple intramuscular injections. Six males and six females received single dose of either 25 mg or 50 mg levosulpiride, or multiple doses of 25 mg every 12 h for 5 consecutive days. In the single 25 mg study, the mean peak plasma concentration (C_max) was 441 ng/mL, the mean area under the concentration–time curve from 0 to 36 h (AUC_0–36) was 1724 ng h/mL, and the mean elimination half-life (t_1/2) was 7.0 h. In the single 50 mg study, the mean C_max was 823 ng/mL, the mean AUC_0–36 was 3748 ng·h/mL, and the mean t_1/2 was 6.8 h. After multiple doses of 25 mg levosulpiride, the average plasma concentration (C_av) was 136 ng/mL, the fluctuation index (DF) was 3.60, and the accumulation ratio (R) was 1.2. Levosulpiride injections appeared to be well tolerated by the subjects, and can be used for successive administration.

Sulpiride for schizophrenia

BACKGROUND

The antipsychotic drug sulpiride was formulated over 20 years ago and was marked as having a low incidence of adverse effects and an effect on the negative symptoms of schizophrenia. This relatively inexpensive antipsychotic drug has a similar neuropharmacological profile to several novel atypical drugs.

OBJECTIVES

To estimate the clinical efficacy and tolerability of sulpiride.

SEARCH STRATEGY

Electronic searches of Biological Abstracts (1982-1997), CINAHL (1982-1998), Cochrane Schizophrenia Group's Register (March 1998), Cochrane Library (Issue 1, 1998), EMBASE (1980-1998), MEDLINE (1966-1998), PsycLIT (1974-1997), SIGLE (1994-1998), and Sociofile (1974-1997) were supplemented by reference searching, contacting authors and the manufacturers of sulpiride.

SELECTION CRITERIA

All randomised or quasi-randomised clinical trials focusing on the use of different doses of sulpiride or comparing sulpiride to (i) placebo; (ii) typical antipsychotic drugs; or (iii) atypical antipsychotic drugs, for those with schizophrenia or serious mental illness were selected.

DATA COLLECTION AND ANALYSIS

Trials were reliably selected and quality rated. Data were independently extracted, by two reviewers (BGOS, MF), and analysed on an intention-to-treat basis. It was assumed that people who did not complete the follow up had no improvement. Authors of trials were contacted for additional and missing data. Relative risk (RR) and 95% confidence intervals (CI) of dichotomous data were calculated with the random effects model and weighted mean difference (WMD) was calculated for continuous data.

MAIN RESULTS

The review currently includes 18 studies (30 citations). Studies are generally small and of poor quality. Limited evidence suggests that there is little difference between sulpiride and other drugs although the incidence of side effects may be less for sulpiride. There are no clear findings relating to negative symptoms.

REVIEWER'S CONCLUSIONS

Sulpiride may be an effective antipsychotic drug but evidence is limited and data relating to claims for its value against negative symptoms is not trial-based.

Determination of clozapine in serum by radioreceptor assay versus high-performance liquid chromatography: possible detection of hydroxy-metabolites

Clozapine is an antipsychotic drug with few extra-pyramidal motor side-effects, used to treat schizophrenia which is resistant to classical neuroleptic therapy. This report shows that norclozapine but not clozapine-N-oxide has the same D2 receptor affinity as clozapine. Assay results suggest a bimodal distribution which may be explained by CYP1A2 polymorphism. Extensive metabolizers could produce other active metabolites, probably other hydroxy-clozapine derivatives.

A risk-benefit assessment of sulpiride in the treatment of schizophrenia

Sulpiride is a substituted benzamide with a selective action on receptors of the dopamine D2-like family, and clinical and pharmacological data suggest that it could be considered to be an atypical antipsychotic. Sulpiride penetrates the blood-brain barrier poorly because of its low lipid solubility. It is mainly excreted unchanged in the urine, and accumulation of the drug could occur in patients with renal dysfunction and possibly in elderly patients with declining glomerular filtration rate. At low dosages (50 to 150 mg/day), sulpiride produces a disinhibiting and antidepressant effect, which is probably related to its action on D2 presynaptic autoreceptors, thus facilitating dopaminergic neurotransmission. Data have confirmed the efficacy of sulpiride in patients with acute or chronic schizophrenia during both short and long term treatment, but long term, placebo-controlled trials are still lacking. It is still doubtful whether sulpiride is more effective than typical antipsychotics for the treatment of negative symptoms. Data from clinical studies are controversial; the majority of authors indicate that sulpiride produces a better recovery rate from negative than from positive symptoms at low doses, but it shows a similar efficacy either on negative and positive symptoms at higher doses. The safety profile of sulpiride is similar to that of typical antipsychotics, although the frequency of adverse effects seems to be globally lower. Extrapyramidal reactions appear generally to be mild. Autonomic effects occur less frequently with sulpiride than with typical antipsychotics, showing no clinically relevant influence on cardiovascular parameters and, on the whole, good tolerability in elderly patients. Sulpiride is known to induce prolactin elevation in both serum and CSF, which may be associated with impotence in men and diminished gonadal function in women; these effects appear to be dosage-dependent. Sulpiride can be considered to be an atypical antipsychotic, considering its action on negative, defective symptoms, its partial activity against positive symptoms, and its low incidence of extrapyramidal adverse effects. Sulpiride could find its specific therapeutic role in elderly patients with schizophrenia, as it shows a good margin of safety between therapeutic dosages and toxic concentrations.

Effects of raclopride treatment on plasma and CSF HVA: relationships with clinical improvement in male schizophrenics

Thirty-two acutely psychotic, male schizophrenic patients received raclopride, at 2, 6, or 12 mg/day, or haloperidol, 15 mg/day for 4 weeks after randomized, double-blind assignment. Twenty-six patients, including 19 who had been assigned one of the three doses of raclopride, completed the study. Raclopride, particularly at 12 mg/day, increased CSF homovanillic acid (HVA) at 4 weeks, and plasma HVA at 2 days, of treatment. The clinical response to raclopride was significantly correlated with plasma raclopride concentrations and baseline plasma HVA concentrations. Although raclopride is a substituted benzamide with atypical properties in animals, these results suggest that the doses of raclopride required for clinical efficacy and elevation of clinical indices of brain dopamine turnover are similar.

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.

Effects of mianserin in chronic schizophrenia

1. The efficacy of mianserin as a supplement in treating chronic schizophrenia was tested by monitoring the BPRS and plasma monoamine metabolites. 2. Twenty inpatients with schizophrenia were administered fixed doses of neuroleptics throughout the study. 3. A control BPRS scoring and blood sampling were done before mianserin administration. 4. Fixed doses of 60 mg/day of mianserin for 2 weeks and flexible doses for 4 weeks were given orally in an open study for 6 consecutive weeks, and no treatment followed for 1 additional week. 5. BPRS scoring was carried out once weekly, and blood samples were obtained after mianserin treatment. 6. Both total BPRS scores and scores for negative symptoms were decreased by mianserin treatment as compared with the control values. 7. 5-HIAA concentrations of both responding patients and nonresponding patients to mianserin were increased after medication; however, 5-HIAA values of responding patients were lower than those of nonresponding patients. 8. HVA concentrations of the responding group were slightly increased by mianserin administration. 9. There were no significant changes in MHPG levels between the two groups. 10. These results suggest that the negative symptoms of schizophrenia are partly improved by mianserin treatment.

Absolute bioavailability, rate of absorption, and dose proportionality of sulpiride in humans

The pharmacokinetics of orally administered sulpiride was determined in a series of three studies. In the first study, 12 subjects received an oral solution (200 mg) and an iv dose (100 mg). The second study also included an iv dose, and examined the absorption of 200-, 300-, and 400-mg doses given as 50-mg capsules to six subjects. The third study compared the bioavailability of a 200-mg capsule dose with a 200-mg im dose in eight subjects. The concentration of sulpiride in plasma, red blood cells, and urine was measured by HPLC. The disposition of the drug was generally best described by a two-compartment pharmacokinetic model, with absorption appearing to occur by two sequential zero-order processes. The fraction of dose absorbed after oral administration was approximately 30% based on plasma and urine data. After the 200-mg dose, the mean elimination half-life was 7.0 h, and the mean residence time was 8.4 h. For each subject, total clearance, corrected for the fraction absorbed, and renal clearance were similar. The dose proportionality study demonstrated linear disposition kinetics.

Pharmacokinetics of sulpiride in humans after intravenous and intramuscular administrations

The pharmacokinetics of sulpiride in plasma, red blood cells (RBC), and urine were investigated after administration of 100 mg by the iv route to 15 subjects and by the im route to 12 subjects. The concentrations of sulpiride in plasma, RBC, and urine were measured by HPLC. All the data were consistent with a two-compartment, open-body model. After iv administration, the mean +/- SD apparent elimination half-life of sulpiride was 6.47 +/- 1.00 h, and the mean +/- SD volume of distribution at steady state was 0.94 +/- 0.23 L/kg. Renal clearance (119.5 +/- 28.2 mL/min) was very close to total clearance (127.8 +/- 26.2 mL/min). In urine, the mean +/- SD recovery in form of the unchanged drug was 90.0 +/- 9.68% of the administered dose, and the excretion rate versus time showed an elimination half-life similar to that found in plasma. The values of all these parameters were very close to those obtained after im administration. The sulpiride partition coefficient between RBC and plasma did not show any significant change as a function of time and concentration, with a mean value +/- SD of 1.00 +/- 0.043, indicating that sulpiride is evenly distributed between RBC and plasma. The pharmacokinetic parameters determined from the plasma and the RBC data were similar.

Mechanisms of action of atypical antipsychotic drugs. Implications for novel therapeutic strategies for schizophrenia

The mechanisms which contribute to the actions of atypical antipsychotic drugs, such as clozapine and the putative atypical agents remoxipride and raclopride, are reviewed. Examination of available preclinical and clinical data leads to two hypotheses concerning the mode of action of atypical antipsychotic drugs. The first hypothesis is that antagonism of the dopamine D2 receptor is both necessary and sufficient for the atypical profile, but that interaction with subtypes of the D2 receptor differentiates typical from atypical antipsychotic drugs. The second hypothesis has been previously advanced, and suggests that a relatively high ratio of serotonin 5-HT2:dopamine D2 receptor antagonism may subserve the atypical profile. It seems likely that the atypical antipsychotic drug profile may be achieved in more than one way.

Neuroendocrine responses to single oral doses of remoxipride and sulpiride in healthy female and male volunteers

Six female and six male healthy volunteers received 100 mg remoxipride, 200 mg sulpiride and placebo as single oral doses in a double blind trial with a randomized crossover design. The main objective was to compare the effect of the two drugs on serum prolactin levels, but effects on other hormones were also investigated. Remoxipride and sulpiride increased the serum levels of prolactin to similar peak levels. This effect was larger in female than in male subjects. Sulpiride increased prolactin levels at much lower plasma concentrations than remoxipride, and sulpiride's effect on prolactin lasted for considerably longer than remoxipride's. No consistent effects on serum levels of LH, FSH, GH, oestradiol, progesterone, testosterone or cortisol could be detected after remoxipride and sulpiride compared to placebo. No drug-related effects on plasma homovanillic acid (HVA) were found.

A specific effect of antipsychotic drugs on protein synthesis in human lymphomononuclear cells

We have studied the effects of psychotropic drugs on patterns of protein synthesis in human lymphomononuclear cells by two-dimensional gel electrophoretic analysis. Drugs effective in treatment of schizophrenia specifically increased the relative synthesis of a 30-kDa polypeptide in cultured human lymphomononuclear cells whereas dopamine (DA) or psychoactive drugs lacking antipsychotic properties did not. The effect was stereospecific with respect to the clinically active and inactive isomers of flupenthixol. Synthesis of the 30-kDa polypeptide appears therefore to be correlated with antipsychotic properties but not with DA receptor binding. It is possible that such effects may be associated with the clinically beneficial effect of antipsychotic drugs in the brain.

Pharmacokinetics of antipsychotic drugs in man

Variability in the outcome of treatment with antipsychotic drugs may be due to differences in compliance and to variations in pharmacokinetics and concentration-response relationships at the receptor level. Among the various chemical classes of neuroleptics, the butyrophenones, the phenothiazines, and the thioxanthenes have similar pharmacokinetics, and show larger inter-individual variations in plasma drug levels after oral than after intramuscular doses. Compared to the "classical" neuroleptics, the more water-soluble benzamide derivatives have significantly shorter elimination half-lives, and show smaller inter-patient variations in plasma level: dose ratios at steady state.

Plasma catecholamine metabolites in schizophrenics: evidence for the two-subtype concept

Plasma homovanillic acid (pHVA) and plasma methoxyhydroxyphenyl glycol (pMHPG), as well as plasma haloperidol, were measured in 33 schizophrenic patients before and during 6 weeks of haloperidol treatment. Good responders had higher baseline pHVA values compared with poor responders (17.4 +/- 8.8 ng/ml, n = 22 versus 11.4 +/- 5.0 ng/ml, n = 11, p less than 0.05). A higher than 15 ng/ml pretreatment pHVA level was associated with a more consistent clinical response to the subsequent treatment. Differential pHVA changes during treatment were also found between good and poor responders. Within the good responder group, a significant decline in pHVA over time was found. By contrast, pHVA showed a transient increase in the poor responder group. Plasma MHPG changes showed a similar pattern during treatment in good responders, although no significant differences in baseline values were found between the good (n = 13) and poor (n = 9) responders, and pMHPG showed no change during treatment in poor responders. Significant correlations between baseline pHVA and pMHPG values were found in 22 patients. Good responders and poor responders did not differ significantly in terms of age, duration of illness, severity of presenting symptoms, haloperidol dose, or plasma drug concentration. Two hypothetical subtypes of schizophrenia and both dopamine and norepinephrine systems involved in schizophrenic psychopathology are proposed.

Relationships between clinical effects and monoamine metabolites and amino acids in sulpiride-treated schizophrenic patients

Twenty-four acutely ill schizophrenic patients (DSM-III-R), 18-42 years old, were treated for 6 weeks with sulpiride. Sulpiride was administered in three different daily dosages (400, 800 or 1200 mg) according to a double dummy blind randomized administration schedule. The psychopathology of the patients was rated by the Comprehensive Psychopathological Rating Scale (CPRS) and the Nurse's Observation Scale for Inpatient Evaluation (NOSIE). The monoamine metabolites homovanillic acid (HVA), 5-hydroxy-indoleacetic acid (5-HIAA), 4-hydroxy-3-methoxy-phenylglycol (HMPG) and the amino acids tyrosine, tryptophan, glutamate and glutamine were measured in serum before and once a week during sulpiride treatment. There were no significant correlations between the CPRS or the NOSIE morbidity scores and the biochemical measures before drug treatment. HVA levels were not correlated to rating scores during treatment, but after 6 weeks HVA had decreased significantly in the patients with a good response but not in the patients with a poor response. A negative relationship between 5-HIAA levels and depressive and negative symptoms was found. Non-responders according to the subscale for depression had low 5-HIAA levels throughout the treatment. An increase of tryptophan was correlated to improvement in the early part of treatment. High levels of glutamate or glutamine were found in non-responders before treatment. During treatment an increase of the glutamate level was correlated to improvement. Low levels of glutamine were related to improvement according to global and NOSIE (total) rating scores. Peripheral biochemical measures may be a valuable tool in the study of pathophysiological mechanisms and treatment effects in patients with schizophrenia.

Pharmacokinetics of sulpiride after intravenous administration in patients with impaired renal function

Single intravenous doses of sulpiride 100 mg were administered to 18 patients with renal function impairment, and 6 healthy volunteers. The plasma concentration-time profile is described by a 2-compartment open model. The differences between the pharmacokinetic parameters of sulpiride for the 2 groups were statistically significant. Elimination half-life, mean residence time and area under the plasma concentration-time curve are significantly greater in renal failure; renal and total clearance, and the cumulative amount of unchanged sulpiride in urine, are significantly reduced but volume of distribution remains unchanged. Creatinine clearance was strongly correlated with renal clearance of sulpiride, elimination rate constant, area under the curve and cumulative amount excreted in urine. For patients with impaired or physiologically reduced renal function receiving long term sulpiride treatment, a 35 to 70% reduction in dose, or extension of the dosage interval by a factor of 1.5 to 3, may be required.

Effects of sulpiride and chlorpromazine on regional cerebral glucose metabolism in schizophrenic patients as determined by positron emission tomography

Positron emission tomography (PET) was used to determine regional brain glucose metabolism in schizophrenic patients (n = 17) before and during neuroleptic treatment. The patients had not been treated with neuroleptics for at least 3 weeks before the first study. All suffered from acute psychotic symptoms and were hospitalized to obtain neuroleptic treatment. After determination of regional brain metabolism without neuroleptic treatment, 11 patients were treated with sulpiride (800 mg/day) and 6 patients were treated with chlorpromazine (400 mg/day) over 5-6 weeks before the second PET investigation. The control group consisted of seven healthy male volunteers, also investigated twice 5 weeks apart. The PET investigation was made with the subject in a resting state. The tracer was uniformly labelled 11C-glucose. The metabolism was determined bilaterally in 15 brain regions cortical, as well as central regions. Metabolic rates differed among the groups. The sulpiride group had lower metabolic rates than the controls and the schizophrenic patients later treated with chlorpromazine. The sulpiride group, in which absolute metabolic rates were determined, were clinically more autistic and chronic than the chlorpromazine group. It was proposed that these facts could explain the lower metabolic rates in the sulpiride group. A significant change in metabolism in relation to drug treatment was only found in one brain region. The selective D2-receptor antagonist sulpiride increased the metabolic rate in the right lentiform nucleus in comparison with the patients treated with chlorpromazine and the controls. Likewise, relative metabolic rates were increased only in the right lentiform nucleus. Negative correlations between intensity of clinical symptoms and metabolism indicated that emotional tone and drive were related to brain metabolism. No correlations were found between drug concentrations and metabolism or clinical symptoms.

Plasma homovanillic acid levels and subtyping of schizophrenia

Plasma levels of homovanillic acid (HVA), a major metabolite of dopamine, were measured in a group of 24 schizophrenic inpatients before and during 6 weeks of haloperidol (HAL) treatment. Steady-state plasma HAL levels were measured in parallel with plasma HVA. Differential plasma HVA responses to HAL treatment were found between good and poor outcome patients. The two groups did not differ significantly in plasma HAL levels. Two hypothetical subtypes of schizophrenia are proposed.

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)

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.

Effects of sulpiride and chlorpromazine on depressive 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) over a period of 8 weeks using a double-blind design. There were 25 patients in each group and all the patients were in an acute phase of their disease. They all fulfilled the Research Diagnostic Criteria (RDC) for schizophrenia. Depressive symptoms as rated according to the Comprehensive Psychopathological Rating Scale (CPRS) were present in the patients before treatment was started. The depressive and psychotic symptoms in both groups decreased in parallel during the whole period of treatment. Patients in the sulpiride group recovered more quickly from depressive symptoms than patients in the CPZ group. It was also found that patients with low concentrations of sulpiride or CPZ in serum recovered more completely from depressive symptoms and had fewer extrapyramidal side effects than patients with high drug concentrations.