Franca Centorrino

International Consensus Study of Antipsychotic Dosing

OBJECTIVE Potency equivalents for anti-psychotic drugs are required to guide clinical dosing and for designing and interpreting research studies. Available dosing guidelines are limited by the methods and data from which they were generated. METHOD With a two-step Delphi method, the authors surveyed a diverse group of international clinical and research experts, seeking consensus regarding antipsychotic dosing. The authors determined median clinical dosing equivalents and recommended starting, target range, and maximum doses for 61 drugs, adjusted for selected clinical circumstances. RESULTS Participants (N=43) from 18 countries provided dosing recommendations regarding treatment of psychotic disorders for 37 oral agents and 14 short-acting and 10 long-acting parenteral agents. With olanzapine 20 mg/day as reference, estimated clinical equivalency ratios of oral agents ranged from 0.025 for sulpiride to 10.0 for trifluperidol. Seventeen patient and treatment characteristics, including age, hepatic and renal function, illness stage and severity, sex, and diagnosis, were associated with dosing modifications. CONCLUSIONS In the absence of adequate prospective, randomized drug-drug comparisons, the present findings provide broad, international, expert consensus-based recommendations for most clinically employed antipsychotic drugs. They can support clinical practice, trial design, and interpretation of comparative antipsychotic trials.

Tissue Concentrations of Clozapine and its Metabolites in the Rat

Clozapine (CLZ) and its metabolites norclozapine (NOR) and clozapine-N-oxide (NOX) were assayed in rat serum and brain tissue after intraperitoneal injection of CLZ. Clozapine levels rose with dose, averaging 28 ng/ml (87 nmol/L) serum per milligram/kilogram dose. Brain- and serum-CLZ levels correlated closely, averaging 24-fold higher in brain. Norclozapine and NOX averaged approximately 58% and 13% of CLZ in serum, respectively, whereas in brain, NOR was detected only at doses greater than or equal to 10 mg/kg (approximately 5.6% of CLZ) and NOX was undetectable. Levels peaked within 30 minutes, and elimination of CLZ from brain and CLZ or NOR from blood was very rapid (half-life = 1.5 to 1.6 hours). A week of daily dosing with CLZ led to no accumulation of drug in brain; a week of fluoxetine pretreatment increased analyte concentrations (serum, 86%; brain, 61%), but valproate had little effect.

Clozapine and metabolites: concentrations in serum and clinical findings during treatment of chronically psychotic patients.

Clozapine (CLZ) and metabolites norclozapine and clozapine-N-oxide were assayed with a new, sensitive (2 pmol), and selective method in 68 serum samples from 44 psychotic subjects, 20 to 54 years old, ill 16 years, and treated with CLZ for 2.2 years (currently at 294 mg, 3.4 mg/kg daily). CLZ levels averaged 239 ng/ml (0.73 microM; 92 ng/ml per mg/kg dose) or 48% of total analytes (norclozapine = 41% [91% of CLZ] and clozapine-N-oxide = 11%); metabolite and CLZ levels were highly correlated (rs = 0.9), and CLZ levels varied with daily dose (rs = 0.7). Sampling twice yielded similar within-subject analyte levels (r = 0.8 to 0.9; difference = 24% to 33%). Range and variance narrowed when levels were expressed per weight-corrected dose (ng/ml per mg/kg). Levels per dose were 40% higher in nonsmoking women than men, despite a 60% lower milligram per kilogram dose in women, and did not vary by diagnosis or age in this limited sample. Fluoxetine increased serum CLZ analytes by 60%; valproate had less effect. Patients rated treatment very positively; observer-assessed benefits typically were more moderate. Common late side effects were sialorrhea (80%), excess sedation (58%), obesity (55% > 200 lb), mild tachycardia (51%), constipation (32%), and enuresis (27%); there were no seizures or leukopenia. There was little evident relationship of drug dose or serum level to current clinical measures or side effect risks.

Comorbid substance-use in schizophrenia: relation to positive and negative symptoms.

As substance use disorders (SUD) are common in schizophrenia patients, we tested the hypothesis that comorbid patients (SUD[+]) have more positive vs. negative symptoms than non-comorbid (SUD[-]) patients. From reports identified by literature-searching we compared Positive and Negative Syndrome Scale (PANSS) ratings in schizophrenia patients with and without SUD using meta-analytic methods. Among 9 comparisons (N=725 subjects), SUD[+] patients were more often men, and abused alcohol>cannabis>cocaine. SUD[+] patients had very significantly higher PANSS-positive, and lower PANSS-negative scores. Comorbid SUD in schizophrenia patients was associated with male sex and higher PANSS positive to lower negative scores. Cause-effect relationships remain to be clarified.

Polymorphisms of the dopamine D4 receptor and response to antipsychotic drugs.

Abstract The dopamine D4 receptor may be a site through which the clinical effects of antipsychotic drugs are mediated. Polymorphisms of a 48 base pair repeat in the third exon of the DRD4 gene code for different length segments in the third intracytoplasmic loop of the D4 receptor. The most common long (seven repeat) form of the D4 receptor has been shown in both physiologic and pharmacologic experiments to respond differently to dopamine agonists and antagonists than do shorter forms of D4. Thus, variants of D4 may partly determine patient response to antipsychotic drugs and, in particular, response to typical neuroleptics, which have a relatively low affinity for the D4 receptor, as compared to clozapine, which has a relatively high affinity for D4. DRD4 polymorphisms in the third intron were characterized in 28 patients with chronic psychosis who responded well to typical neuroleptics, 32 patients who responded well to clozapine, and 57 healthy comparison subjects. Patients responding to typical neuroleptics carried the allele for the long (seven repeat) form of the D4 receptor (allele frequency 8.9%) less frequently than patients responding to clozapine (allele frequency 23.4%, P = 0.046) or healthy comparison subjects (allele frequency 26.3%, P = 0.004). The results of this study suggest that inherited variants of D4 may explain some of the interindividual variation seen in patient response to different classes of antipsychotic medication.

Advances in atypical antipsychotics for the treatment of schizophrenia: new formulations and new agents.

Innovation in atypical antipsychotic agents continues with new preparations of available drugs as well as novel agents. In this article, we provide an update on these novel products by reviewing information from a computerised literature search, recent abstracts and discussions with industry representatives.A generic formulation of clozapine is now available. It may be less well absorbed and/or less effective than Clozaril®1, although evidence is conflicting. A fatty acid amide derivative of clozapine is in early development.A liquid formulation of risperidone is currently available, which may be a useful treatment for psychotic agitation as well as a preferable alternative to tablets for some patients. A depot formulation is in development for the long-term management of psychosis.An orally disintegrating tablet formulation of olanzepine is a useful alternative to standard tablets. A short-acting injectable formulation of the drug is in development for psychotic agitation.Sachets and slow-release formulations of quetiapine are in development. Ziprasidone, a recently launched agent, is available in tablet form for schizophrenia/schizoaffective disorder, psychotic depression and mania. A short-acting injectable formulation is in development for psychotic agitation.Aripiprazole (tablets) and iloperidone (tablets and depot injection) are two antipsychotics in development for schizophrenia/schizoaffective disorder (available information regarding iloperidone is very limited).These new formulations and agents should broaden options for the treatment of psychosis.

Weight loss in overweight patients maintained on atypical antipsychotic agents

Background:Weight gain and associated medical morbidity offset the reduction of extrapyramidal side effects associated with atypical antipsychotics. Efforts to control weight in antipsychotic-treated patients have yielded limited success.Methods:We studied the impact of an intensive 24-week program of diet, exercise, and counseling in 17 chronically psychotic patients (10 women, seven men) who entered at high average body weight (105.0±18.4 kg) and body mass index (BMI) (36.6±4.6 kg/m2). A total of 12 subjects who completed the initial 24 weeks elected to participate in an additional 24-week, less intensive extension phase.Results:By 24 weeks, weight-loss/patient averaged 6.0 kg (5.7%) and BMI decreased to 34.5 (by 5.7%). Blood pressure decreased from 130/83 to 116/74 (11% improvement), pulse fell slightly, and serum cholesterol and triglyceride concentrations changed nonsignificantly. With less intensive management for another 24 weeks, subjects regained minimal weight (0.43 kg).Conclusions:These findings add to the emerging view that weight gain is a major health problem associated with modern antipsychotic drugs and that labor-intensive weight-control efforts in patients requiring antipsychotic treatment yield clinically promising benefits. Improved treatments without weight-gain risk are needed.

Clozapine and body mass change

BACKGROUND Patients treated with clozapine have been reported to gain weight. We hypothesized that patients would also experience an increase in body mass, which can be more directly related to cardiovascular morbidity. METHODS Forty-two patients who had been treated with clozapine for at least 1 year were weighed and measured, and waist-hip ratios (WHR) and body mass index (BMI), measured as kg/m2, were calculated. Patients were also asked about a series of factors potentially related to change in body mass. RESULTS Female patients gained both weight and body mass. Their WHR after 37 months of clozapine therapy was .83, with a significant increase in BMI from 23.2 to 29.1 kg/m2 (p = .001). Male subjects also gained weight and body mass. Their WHR after 39 months of clozapine therapy was .93, with a significant increase in BMI from 26.4 to 29.7 kg/m2 (p < .001). Stepwise multiple-regression analysis showed that factors related to final body mass were initial body mass, dose of clozapine, and decrease in smoking. Baseline BMI contributed most to the final BMI, but the addition of dose and decrease in smoking made significant contributions to the model. CONCLUSIONS Both female and male patients treated with clozapine gain body mass. This may place them at greater risk for cardiovascular morbidity.

Weygandt's On the Mixed States of Manic-Depressive Insanity: A Translation and Commentary on Its Significance in the Evolution of the Concept of Bipolar Disorder

Wilhelm Weygandts Über die Mischzustände des manisch-depressiven Irreseins (On the Mixed States of Manic-Depressive Insanity) describes and conceptualizes mixed states of mood, behavior, and thinking commonly found in manic-depressive disorders. These ideas emerged from Weygandts service in the 1890s at the Psychiatric Clinic of the University of Heidelberg, directed by Emil Kraepelin. In the sixth (1899) edition of Kraepelins influential textbook, the concept of manic-depressive illnesses underwent a fundamental shift from a complex group of syndromal subtypes to a single integrated disorder, widely known from the 1921 English translation of the eighth (1920) edition. In the 1899 edition, Kraepelin acknowledged Weygandt for a new section on mixed manic-depressive states within the new integrated view of manic-depressive disorder. We provide biographical notes on Weygandt, a little-known but historically important figure, as well as the first English translation of his monograph and interpretive summaries of his findings. We also consider whether Weygandts important insight that the same person could be both manic and depressed not only at different times but even at the same time served as an important stimulus to Kraepelins unified manic-depressive disorder concept, which survives as bipolar disorder a century later.

The effect of clozapine on saliva flow rate : A pilot study

This study examined the effect of clozapine on saliva flow rate. Unstimulated whole saliva was collected from 9 patients taking clozapine (dose range = 50-400 mg/day) and from 8 controls who had never used clozapine. There was no significant difference between the average saliva flow rates in the two groups (p > .10), nor was there significant correlation between saliva flow rate and daily clozapine dose (p > .10). Alternative explanations for observations or complaints of excessive salivation, drooling, or a choking feeling while taking clozapine are proposed.