Blood levels of reduced haloperidol versus clinical efficacy and extrapyramidal side effects of haloperidol

The Relation between the Plasma Concentrations of Long-Acting Atypical Antipsychotics and Clinical Effectiveness in Patients Affected by Schizophrenia or Schizoaffective Disorder: A Comprehensive Overview

Atypical antipsychotic depot medications are currently recommended for patients with schizophrenia (SCZ) to prevent relapse and ameliorate the long-term prognosis of these patients. This review critically summarizes the available data about the association between the plasma concentrations of long-acting Second- Generation Antipsychotics (SGAs) and the clinical effectiveness of these compounds in patients affected by SCZ or schizoaffective disorder. Our question is if the measurement of these concentrations can be helpful for clinicians in predicting treatment response and clinical stabilization of patients. Bibliographic research on the main databases was performed, and 13 studies were finally included in this review. Contrasting results were found between plasma concentrations of long-acting injectable (LAI) risperidone and clinical amelioration according to rating scale scores. Data are too scanty to draw conclusions for olanzapine and paliperidone. In contrast, despite small sample sizes, data are quite concordant in showing a relation between long-acting SGA plasma concentrations and D2 receptor occupancy. Despite the preliminary encouraging results, particularly for D2 receptor occupancy, future research with larger samples will have to confirm the clinical usefulness of measuring LAI SGA plasma concentrations to predict the clinical response of patients affected by severe mental conditions such as SCZ.

The Associations between Central Nervous System Diseases and Haemostatic Disorders

The aim of this review was to examine the relationship between the occurrence of central nervous system (CNS) diseases, the medicines used in their treatment and the blood coagulation process. The paper mainly focuses on the effects of antidepressant and antipsychotic drugs. Special attention has been paid to the influence of drugs on platelets, the vascular endothelium, plasma coagulation and fibrinolysis, regarding coagulation.

Classics in Chemical Neuroscience: Haloperidol

The discovery of haloperidol catalyzed a breakthrough in our understanding of the biochemical basis of schizophrenia, improved the treatment of psychosis, and facilitated deinstitutionalization. In doing so, it solidified the role for chemical neuroscience as a means to elucidate the molecular underpinnings of complex neuropsychiatric disorders. In this Review, we will cover aspects of haloperidol's synthesis, manufacturing, metabolism, pharmacology, approved and off-label indications, and adverse effects. We will also convey the fascinating history of this classic molecule and the influence that it has had on the evolution of neuropsychopharmacology and neuroscience.

Relationship between CYP2D6 genotype and haloperidol pharmacokinetics and extrapyramidal symptoms in healthy volunteers

Aim: This study aimed to elucidate the relationship between CYP2D6 genotype and haloperidol pharmacokinetics and induced extrapyramidal symptoms (EPSs). Materials & methods: Twenty five healthy subjects were included in this randomized, placebo-controlled, single-dose (5 mg) crossover and double-blind clinical trial, selected according to their CYP2D6 genotype and classified as poor metabolizers (n = 8), extensive metabolizers (n = 10) and ultrarapid metabolizers (n = 7). Results & conclusion: We confirm that CYP2D6 genotype partially determines haloperidol metabolism and the rate of EPSs measured as wakefulness activity by actigraphy. The best predictor of wakefulness activity was the model including haloperidol area under the plasma concentration–time curve, sex and tranquilization, which explained 48.3% of the total variance. However, other markers need to be identified in order to explain the observed variability of haloperidol response and to develop pharmacogenetic predictors of haloperidol-induced EPSs.

Determination of haloperidol and reduced haloperidol in human serum by liquid chromatography after fluorescence labeling based on the Suzuki coupling reaction

A simultaneous method for the determination of haloperidol (HP) and its metabolite, reduced haloperidol (RHP), in human serum was developed by means of high-performance liquid chromatography (HPLC) with fluorescence detection. Suzuki coupling reaction with a fluorescent arylboronic acid, 4-(4,5-diphenyl-1H-imidazol-2-yl)phenylboronic acid (DPA), was employed to convert HP and RHP into highly fluorescent compounds. HP and RHP were extracted from human serum by liquid-liquid extraction with a mixture of n-hexane and isoamyl alcohol (99:1, v/v) and subsequently labeled by reaction with DPA. Separation of DPA derivatives of HP and RHP was performed on a silica column with a mixture of acetonitrile and H(2)O (90:10, v/v) containing triethylamine and acetic acid as a mobile phase. The proposed method allowed sensitive detection of HP and RHP in human serum with a detection limit (at a signal to noise ratio of 3) of 0.22 and 0.20 ng/mL, respectively. The applicability of the method for therapeutic drug monitoring (TDM) was demonstrated by analyzing human serum samples from schizophrenic patients receiving HP.

Simultaneous determination of haloperidol and bromperidol and their reduced metabolites by liquid–liquid extraction and automated column-switching high-performance liquid chromatography

This study describes a new simultaneous determination of haloperidol and bromperidol and their reduced metabolites by modification of automated column-switching high-performance liquid chromatography. The test compounds were extracted from 1ml of plasma using chloroform-hexane (30:70 (v/v)), and the extract was injected into a hydrophilic metaacrylate polymer column for clean-up and a C(18) analytical column for separation. The mobile phases consisted of phosphate buffer (0.02M, pH 4.6), perchloric acid (60%) and acetonitrile (54:1:45 (v/v)) and was delivered at a flow-rate of 0.6ml/min. The peak was detected using a UV detector set at 215nm. The method was validated for the concentration range 1-100ng/ml, and good linearity (r >0.999) was confirmed. Intra-day coefficient variations (CVs) for haloperidol, reduced haloperidol, bromperidol and reduced bromperidol were less than 2.5, 3.1, 2.4 and 2.5%, respectively. Inter-day CVs for corresponding compounds were 3.9, 5.1, 2.6 and 4.4%, respectively. Relative errors ranged from -5 to 10% and mean recoveries were 96-100%. The limit of quantification was 1.0ng/m for each compound. This method shows good specificity with respect to commonly prescribed psychotropic drugs, and it could be successfully applied for pharmacokinetic studies and therapeutic drug monitoring, particularly in patients receiving both haloperidol and bromperidol.

Poor reliability of therapeutic drug monitoring data for haloperidol and bromperidol using enzyme immunoassay

Therapeutic drug monitoring (TDM) services for plasma concentrations of haloperidol and bromperidol using enzyme immunoassay (EIA) methods are available in Japan, whereas high-performance liquid chromatographic (HPLC) methods are preferred in other countries. To compare these methods, we took 54 plasma samples for haloperidol and 91 plasma samples for bromperidol from schizophrenic patients receiving haloperidol or bromperidol, and the samples were measured using both commercial EIA and HPLC methods. Significant linear correlations were found between the two methods in determining haloperidol (EIA = 1.351 x HPLC + 1.39; r = 0.934, P < 0.001) and bromperidol (EIA = 1.420 x HPLC + 0.712; r = 0.956, P < 0.001) concentrations, but plasma concentrations using the EIA kits were approximately 92% (95% CI; 53-131%) and 62% (54-70%) higher than those using HPLC for haloperidol and bromperidol, respectively. Mean (and range) plasma concentrations of reduced metabolites were 54% (30-92%) and 55% (29-111%) of those of haloperidol and bromperidol, respectively. The present study suggests that reduced metabolites are included to a considerable degree in TDM data using the EIA kits. Therefore, some limitation of TDM data of haloperidol and bromperidol using the EIA kits, ie, high precision but poor accuracy, should be kept in mind.

Histamine H1-receptor antagonists, promethazine and homochlorcyclizine, increase the steady-state plasma concentrations of haloperidol and reduced haloperidol

The effects of histamine H1-receptor antagonists, promethazine and homochlorcyclizine, both of which are inhibitors of CYP2D6, on the steady-state plasma concentrations (Css) of haloperidol and reduced haloperidol were studied in 23 schizophrenic inpatients receiving haloperidol, 12 to 36 mg/d, for 2 to 29 weeks. Promethazine, 150 mg/d, in 11 patients and homochlorcyclizine, 60 mg/d, in the others were coadministered for at least 1 week. Blood sampling was performed before and during coadministration of promethazine or homochlorcyclizine and 1 week after the discontinuation, together with clinical assessments by Brief Psychiatric Rating Scale (BPRS) and Udvalg for kliniske undersogelser (UKU) side effect rating scale. The Css (mean +/- SD) of haloperidol and reduced haloperidol during promethazine coadministration (27.6 +/- 24.9 and 8.6 +/- 13.2 ng/mL) were significantly higher than those before the coadministration (12.7 +/- 10.8 and 5.0 +/- 6.0 ng/mL; P < 0.01) or 1 week after the discontinuation (15.6 +/- 14.8 and 5.8 +/- 7.9 ng/mL; P < 0.05). The Css of haloperidol and reduced haloperidol during homochlorcyclizine coadministration (14.9 +/- 8.1 and 6.4 +/- 5.4 ng/mL) were also significantly higher than those before the coadministration (10.9 +/- 7.2 and 3.8 +/- 3.6 ng/mL; P < 0.01) or 1 week after the discontinuation (12.9 +/- 7.4 and 4.8 +/- 4.1 ng/mL; P < 0.05). No change in BPRS or UKU score was found throughout the study. Thus, the current study suggests that coadministration of clinical doses of promethazine and homochlorcyclizine increases the Css of haloperidol and reduced haloperidol via the inhibitory effects on the CYP2D6-catalyzed metabolism of haloperidol and reduced haloperidol.

Extrapyramidal symptom profiles in Japanese patients with schizophrenia treated with olanzapine or haloperidol

Previous clinical trials have clearly shown the superiority of olanzapine to haloperidol in the improvement of extrapyramidal symptoms (EPS) in schizophrenic patients. The primary purpose of this study was to compare EPS profiles in Japanese schizophrenic patients treated with an atypical antipsychotic, olanzapine, or a typical antipsychotic, haloperidol, as measured by the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). The DIEPSS, which consists of eight individual parameters and one global assessment (overall severity), was used to evaluate 182 patients enrolled in this 8-week study. The primary safety analysis was maximum change (that could be either a decrease or increase) from baseline in DIEPSS total score. Secondary analyses included change from baseline to maximum in DIEPSS total score, change from baseline to endpoint (LOCF) in DIEPSS total score, and the rank sum of the maximum change (that could be either a decrease or increase) from baseline in the DIEPSS individual items. Incidence of treatment-emergent EPS adverse events using the DIEPSS scale was also analyzed. The olanzapine group showed statistically significant superiority to the haloperidol group on the primary analysis (p<0.001). Secondary analyses also demonstrated olanzapine's superiority in DIEPSS total, parkinsonism, akathisia and overall severity scores (all p< or =0.014). Categorical analysis of treatment-emergent akathisia and parkinsonism syndromes at endpoint showed improvement in the olanzapine group but worsening in the haloperidol group. The results from this study suggest that olanzapine, as in Caucasian populations, is a safe treatment in Japanese patients chronically ill with schizophrenia.

Olanzapine versus haloperidol in the treatment of patients with chronic schizophrenia: results of the Japan multicenter, double-blind olanzapine trial

This randomized double-blind trial was conducted to test the efficacy and safety of olanzapine in Japanese patients with schizophrenia. Importantly, this study also represents the first large clinical trial of olanzapine conducted in an Asian population. Patients (n = 182) were randomly assigned to treatment with olanzapine or haloperidol over a period of 8 weeks. The primary analyses included: (i) a test of non-inferiority of olanzapine compared with haloperidol in efficacy using the Final Global Improvement Rating (FGIR); and (ii) comparison between the treatment groups in extrapyramidal symptom severity using the Drug-Induced Extrapyramidal Symptoms Scale (DIEPSS). Olanzapine was comparable to haloperidol in efficacy in treating positive symptoms and significantly superior in treating negative symptoms. Extrapyramidal symptom severity was significantly improved for olanzapine-treated patients versus haloperidol-treated patients. Olanzapine was shown to be more effective and better tolerated than haloperidol in the treatment of Japanese patients suffering from chronic schizophrenia.

Effects of itraconazole on the steady-state plasma concentrations of haloperidol and its reduced metabolite in schizophrenic patients: in vivo evidence of the involvement of CYP3A4 for haloperidol metabolism

The effects of itraconazole, a potent inhibitor of cytochrome P450 (CYP) 3A4, on the steady-state plasma concentrations of haloperidol and reduced haloperidol were examined in schizophrenic patients. Thirteen schizophrenic patients treated with haloperidol 12 or 24 mg/day received 200 mg/day of itraconazole for 7 days. Plasma concentrations of haloperidol and reduced haloperidol were measured by high-performance liquid chromatography together with clinical assessment by the Brief Psychiatric Rating Scale (BPRS) and the Udvalg for Kliniske Undersogelser side effect rating scale just before and during itraconazole treatment and 1 week after its discontinuation. Plasma concentrations of haloperidol and reduced haloperidol during the itraconazole treatment (16.9 +/- 11.2 and 6.1 +/- 6.6 ng/mL, respectively) were significantly (p < 0.01) higher than those observed before itraconazole treatment (13.0 +/- 7.9 and 4.9 +/- 5.1 ng/mL) or 1 week after its discontinuation (13.5 +/- 8.2 and 4.9 +/- 5.0 ng/mL). No change was found in clinical symptoms assessed by BPRS, whereas neurologic side effects were significantly (p < 0.05) increased during itraconazole coadministration. The elevated plasma concentrations of haloperidol and reduced haloperidol during itraconazole coadministration were likely due to the inhibitory effects of itraconazole on the metabolism of haloperidol and reduced haloperidol. Thus, this study may provide in vivo evidence of involvement of CYP3A4 in the metabolism of haloperidol and possibly in that of reduced haloperidol. Deterioration of neurologic side effects during itraconazole treatment may result from the increased plasma concentrations of haloperidol and reduced haloperidol during itraconazole treatment.

Correlation between steady-state plasma concentrations (Css) of bromperidol and haloperidol

1. Bromperidol is a close structural analogue of haloperidol, and its metabolic pathways are similar to those of haloperidol. The authors studied the correlation between the Css of bromperidol and haloperidol. 2. The subjects were 16 schizophrenic inpatients. Fourteen patients received firstly bromperidol 12 mg/day and secondly haloperidol 12 mg/day, while the remaining two patients received the two treatments in the opposite sequence. 3. Blood samplings were performed 2-3 weeks after the initiation of each treatment, and the Css of bromperidol, haloperidol and their reduced metabolites were measured by high-performance liquid chromatography. 4. Neither the correlation between the Css of bromperidol and haloperidol (r = 0.246) nor that between the Css of reduced bromperidol and reduced haloperidol (r = 0.142) was significant. 5. The present study thus suggests that the Css of bromperidol and haloperidol do not correlate well in individuals.

Dose-dependent reduced haloperidol/haloperidol ratios: influence of patient-related variables

Plasma reduced haloperidol (RH) concentrations or RH to haloperidol (HL) ratios have been suggested to be important in determining the clinical efficacy and extrapyramidal side effects of HL. In this study, we measured the steady-state plasma HL and RH levels by high performance liquid chromatography and analyzed the effects of various variables (dose, gender, age, and body weight) on RH/HL ratios in four dose groups of Chinese schizophrenic inpatients: 10 mg/day (n = 84), 20 (n = 111), 30 (n = 29), and 60 (n = 55). In addition, the polymorphic distribution of RH/HL ratios, suggested by previous investigators, was further tested in each dosage group (for controlling the potential dosage effect on RH/HL ratios). As a result, both age and body weight could influence RH/HL ratios. Each year increase in age (after adjusting the effects of gender, body weight, and dosage) would elevate the RH/HL ratio by 0.0067 (P < 0.0001). On the other hand, after adjusting gender, age, and dosage effects, each kg increment in body weight would decrease the RH/HL ratio by 0.0044 (P < 0.01). Gender did not influence the ratio. Furthermore, the high dosage groups had higher RH/HL ratios (even with other variables being controlled). In comparison with the 10 mg group, the 60 mg group exhibited a higher mean RH/HL ratio by 0.84 (P < 0.0001) and the 30 mg group did by 0.31 (P < 0.0001). The 20 mg group was almost equal to the 10 mg group in RH/HL ratios. Besides, at each dosage group, the frequency distribution of RH/HL ratios seemed to be predominantly unimodal with a small proportion of extreme outliers. The results of this study clearly indicate that aging or a high dose (> or = 30 mg/day) of HL could raise the plasma RH/HL ratio, while an increasing body weight would reduce that. In contrast, gender does not affect the ratios.