Safety and efficacy of artesunate treatment in severely injured patients with traumatic hemorrhage. The TOP-ART randomized clinical trial.

PURPOSE: This study aimed at determining whether intravenous artesunate is safe and effective in reducing multiple organ dysfunction syndrome in trauma patients with major hemorrhage. METHODS: TOP-ART, a randomized, blinded, placebo-controlled, phase IIa trial, was conducted at a London major trauma center in adult trauma patients who activated the major hemorrhage protocol. Participants received artesunate or placebo (2:1 randomization ratio) as an intravenous bolus dose (2.4 mg/kg or 4.8 mg/kg) within 4 h of injury. The safety outcome was the 28-day serious adverse event (SAE) rate. The primary efficacy outcome was the 48 h sequential organ failure assessment (SOFA) score. The per-protocol recruitment target was 105 patients. RESULTS: The trial was terminated after enrolment of 90 patients because of safety concerns. Eighty-three participants received artesunate (n = 54) or placebo (n = 29) and formed the safety population and 75 met per-protocol criteria (48 artesunate, 27 placebo). Admission characteristics were similar between groups (overall 88% male, median age 29 years, median injury severity score 22), except participants who received artesunate were more shocked (median base deficit 9 vs. 4.7, p = 0.042). SAEs occurred in 17 artesunate participants (31%) vs. 5 who received placebo (17%). Venous thromboembolic events (VTE) occurred in 9 artesunate participants (17%) vs. 1 who received placebo (3%). Superiority of artesunate was not supported by the 48 h SOFA score (median 5.5 artesunate vs. 4 placebo, p = 0.303) or any of the trial's secondary endpoints. CONCLUSION: Among critically ill trauma patients, artesunate is unlikely to improve organ dysfunction and might be associated with a higher VTE rate.

Health economic analysis for the 'CURE Project' pilot: a hospital-based tobacco dependency treatment service in Greater Manchester.

INTRODUCTION: Treating tobacco dependency in patients admitted to acute care National Health Service (NHS) trusts is a key priority in the NHS 10-year plan. This paper sets out the results of a health economic analysis for 'The CURE Project' pilot; a new hospital-based tobacco dependency service. METHODS: A health economic analysis to understand the costs of the intervention (both for the inpatient service and postdischarge costs), the return on investment (ROI) and the cost per quality-adjusted life year (QALY) of the CURE Project pilot in Greater Manchester. ROI and cost per QALY were calculated using the European Study on Quantifying Utility of Investment in Protection from Tobacco and Greater Manchester Cost Benefit Analysis Tools. RESULTS: The total intervention costs for the inpatient service in the 6-month CURE pilot were £96 224 with a cost per patient who smokes of £40.21. The estimated average cost per patient who was discharged on pharmacotherapy was £97.40. The cost per quit (22% quit rate for smokers at 12 weeks post discharge) was £475. The gross financial ROI ratio was £2.12 return per £1 invested with a payback period of 4 years. The cashable financial ROI ratio was £1.06 return per £1 invested with a payback period of 10 years. The public value ROI ratio was £30.49 per £1 invested. The cost per QALY for this programme was £487. DISCUSSION: The CURE Project pilot has been shown to be exceptionally cost-effective with highly significant ROI in this health economic analysis. This supports the NHS priority to embed high-quality tobacco addiction treatment services in acute NHS trusts, and the CURE Project provides a blueprint and framework to achieve this.

Feasibility, uptake and impact of a hospital-wide tobacco addiction treatment pathway: Results from the CURE project pilot.

INTRODUCTION: Providing comprehensive tobacco addiction treatment to smokers admitted to acute care settings represents an opportunity to realise major health resource savings and population health improvements. METHODS: The CURE project is a hospital-wide tobacco addiction treatment service piloted in Wythenshawe Hospital, Manchester, UK. The core components of the project are electronic screening of all patients to identify smokers; the provision of brief advice and pharmacotherapy by frontline staff; opt-out referral of smokers to a specialist team for inpatient behavioural interventions; and continued support after discharge. RESULTS: From 01 October 2018 to 31 March 2019, 92% (13,515/14,690) of adult admissions were screened for smoking status, identifying 2,393 current smokers. Of these, 96% were given brief advice to quit by the admitting team. Through the automated 'opt-out' referral process, 61% patients completed inpatient behavioural interventions with a specialist cessation practitioner (69% within the first 48 hours of admission). Overall, 66% of smokers were prescribed pharmacotherapy. Over one in five of all smokers admitted during this pilot reported that they were abstinent from smoking 12 weeks after discharge (22%) at a cost £183 per quit. DISCUSSION: National implementation of this cost-effective programme would be likely to generate substantial benefits to public health.

Data-driven Development of ROTEM and TEG Algorithms for the Management of Trauma Hemorrhage: A Prospective Observational Multicenter Study.

OBJECTIVE: Developing pragmatic data-driven algorithms for management of trauma induced coagulopathy (TIC) during trauma hemorrhage for viscoelastic hemostatic assays (VHAs). BACKGROUND: Admission data from conventional coagulation tests (CCT), rotational thrombelastometry (ROTEM) and thrombelastography (TEG) were collected prospectively at 6 European trauma centers during 2008 to 2013. METHODS: To identify significant VHA parameters capable of detecting TIC (defined as INR > 1.2), hypofibrinogenemia (< 2.0 g/L), and thrombocytopenia (< 100 x10/L), univariate regression models were constructed. Area under the curve (AUC) was calculated, and threshold values for TEG and ROTEM parameters with 70% sensitivity were included in the algorithms. RESULTS: A total of, 2287 adult trauma patients (ROTEM: 2019 and TEG: 968) were enrolled. FIBTEM clot amplitude at 5 minutes (CA5) had the largest AUC and 10 mm detected hypofibrinogenemia with 70% sensitivity. The corresponding value for functional fibrinogen (FF) TEG maximum amplitude (MA) was 19 mm. Thrombocytopenia was similarly detected using the calculated threshold EXTEM-FIBTEM CA5 30 mm. The corresponding rTEG-FF TEG MA was 46 mm. TIC was identified by EXTEM CA5 41 mm, rTEG MA 64 mm (80% sensitivity). For hyperfibrinolysis, we examined the relationship between viscoelastic lysis parameters and clinical outcomes, with resulting threshold values of 85% for EXTEM Li30 and 10% for rTEG Ly30.Based on these analyses, we constructed algorithms for ROTEM, TEG, and CCTs to be used in addition to ratio driven transfusion and tranexamic acid. CONCLUSIONS: We describe a systematic approach to define threshold parameters for ROTEM and TEG. These parameters were incorporated into algorithms to support data-driven adjustments of resuscitation with therapeutics, to optimize damage control resuscitation practice in trauma.

Is it still a real treat? Adults' treat provision to children.

Consumption of high-energy foods in the absence of hunger has been identified as a key target to address in the area of obesity. For children, such foods are often provided by adults as treats. There is limited understating of adults' treat giving. The present study aimed to understand adults' provision of treats to children on the Island of Ireland. A total of 1039 participants, including parents, grandparents, child minders and education practitioners completed a face-to-face survey in their home. Participants defined their treats for children primarily as 'something nice', 'deserved/earned' and 'something special'. The top three motivations for treat foods provision were 'to reward for good behaviour' (42.3%), 'because the child(ren) ask' (42.2%) and 'to make the child(ren) feel better' (29.4%). Almost all participants would provide treat foods at celebrations and 52.5% always did so. In addition, 68% participants had structured weekly and/or daily treat for children. Treats provided to children were dominated by energy-dense foods. The top three were sweets, chocolates and ice-creams, being used by 45.2%, 45.1% and 38.8% participants. Variations were observed across different adult groups, in terms of their treat giving behaviour. The main observation was that adults' treat foods provision has become habitual. The findings can help develop targeted strategies to encourage the reduction or replacement of food treats for children.

iTACTIC - implementing Treatment Algorithms for the Correction of Trauma-Induced Coagulopathy: study protocol for a multicentre, randomised controlled trial.

BACKGROUND: Traumatic injury is the fourth leading cause of death globally. Half of all trauma deaths are due to bleeding and most of these will occur within 6 h of injury. Haemorrhagic shock following injury has been shown to induce a clotting dysfunction within minutes, and this early trauma-induced coagulopathy (TIC) may exacerbate bleeding and is associated with higher mortality and morbidity. In spite of improved resuscitation strategies over the last decade, current transfusion therapy still fails to correct TIC during ongoing haemorrhage and evidence for the optimal management of bleeding trauma patients is lacking. Recent publications describe increasing the use of Viscoelastic Haemostatic Assays (VHAs) in trauma haemorrhage; however, there is insufficient evidence to support their superiority to conventional coagulation tests (CCTs). METHODS/DESIGN: This multicentre, randomised controlled study will compare the haemostatic effect of an evidence-based VHA-guided versus an optimised CCT-guided transfusion algorithm in haemorrhaging trauma patients. A total of 392 adult trauma patients will be enrolled at major trauma centres. Participants will be eligible if they present with clinical signs of haemorrhagic shock, activate the local massive haemorrhage protocol and initiate first blood transfusion. Enrolled patients will be block randomised per centre to either VHA-guided or CCT-guided transfusion therapy in addition to that therapy delivered as part of standard care, until haemostasis is achieved. Patients will be followed until discharge or 28 days. The primary endpoint is the proportion of subjects alive and free of massive transfusion (less than 10 units of red blood cells) at 24 h. Secondary outcomes include the effect of CCT- versus VHA-guided therapy on organ failure, total hospital and intensive care lengths of stay, health care resources needed and mortality. Surviving patients will be asked to complete a quality of life questionnaire (EuroQol EQ-5DTM) at day 90. DISCUSSION: CCTs have traditionally been used to detect TIC and monitor response to treatment in traumatic major haemorrhage. The use of VHAs is increasing, but limited evidence exists to support the superiority of these technologies (or comparatively) for patient-centred outcomes. This knowledge gap will be addressed by this trial. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT02593877 . Registered on 15 October 2015. Trial sponsor Queen Mary University of London The contact person of the above sponsor organisation is: Dr. Sally Burtles, Director of Research Services and Business Development, Joint Research Management Office, QM Innovation Building, 5 Walden Street, London E1 2EF; phone: 020 7882 7260; Email: sponsorsrep@bartshealth.nhs.uk Trial sites Academic Medical Centre, Amsterdam, The Netherlands Kliniken der Stadt Köln gGmbH, Cologne, Germany Rigshospitalet (Copenhagen University Hospital), Copenhagen, Denmark John Radcliff Hospital, Oxford, United Kingdom Oslo University Hospital, Oslo, Norway The Royal London Hospital, London, United Kingdom Centre for Trauma Sciences, Blizard Institute, Queen Mary University of London, London, United Kingdom Health Economics Research Centre, Nuffield Department of Population Health, University of Oxford, Oxford, United Kingdom Sites that are planning to start recruitment in mid/late 2017 Nottingham University Hospitals, Queen's Medical Centre, Nottingham, United Kingdom University of Kansas Hospital (UKH), Kansas City, MO, USA Protocol version: 3.0/14.03.2017 (Additional file 1).

Activated Protein C Drives the Hyperfibrinolysis of Acute Traumatic Coagulopathy.

BACKGROUND: Major trauma is a leading cause of morbidity and mortality worldwide with hemorrhage accounting for 40% of deaths. Acute traumatic coagulopathy exacerbates bleeding, but controversy remains over the degree to which inhibition of procoagulant pathways (anticoagulation), fibrinogen loss, and fibrinolysis drive the pathologic process. Through a combination of experimental study in a murine model of trauma hemorrhage and human observation, the authors' objective was to determine the predominant pathophysiology of acute traumatic coagulopathy. METHODS: First, a prospective cohort study of 300 trauma patients admitted to a single level 1 trauma center with blood samples collected on arrival was performed. Second, a murine model of acute traumatic coagulopathy with suppressed protein C activation via genetic mutation of thrombomodulin was used. In both studies, analysis for coagulation screen, activated protein C levels, and rotational thromboelastometry (ROTEM) was performed. RESULTS: In patients with acute traumatic coagulopathy, the authors have demonstrated elevated activated protein C levels with profound fibrinolytic activity and early depletion of fibrinogen. Procoagulant pathways were only minimally inhibited with preservation of capacity to generate thrombin. Compared to factors V and VIII, proteases that do not undergo activated protein C-mediated cleavage were reduced but maintained within normal levels. In transgenic mice with reduced capacity to activate protein C, both fibrinolysis and fibrinogen depletion were significantly attenuated. Other recognized drivers of coagulopathy were associated with less significant perturbations of coagulation. CONCLUSIONS: Activated protein C-associated fibrinolysis and fibrinogenolysis, rather than inhibition of procoagulant pathways, predominate in acute traumatic coagulopathy. In combination, these findings suggest a central role for the protein C pathway in acute traumatic coagulopathy and provide new translational opportunities for management of major trauma hemorrhage.

Leukotriene B4-Neutrophil Elastase Axis Drives Neutrophil Reverse Transendothelial Cell Migration In Vivo.

Breaching endothelial cells (ECs) is a decisive step in the migration of leukocytes from the vascular lumen to the extravascular tissue, but fundamental aspects of this response remain largely unknown. We have previously shown that neutrophils can exhibit abluminal-to-luminal migration through EC junctions within mouse cremasteric venules and that this response is elicited following reduced expression and/or functionality of the EC junctional adhesion molecule-C (JAM-C). Here we demonstrate that the lipid chemoattractant leukotriene B4 (LTB4) was efficacious at causing loss of venular JAM-C and promoting neutrophil reverse transendothelial cell migration (rTEM) in vivo. Local proteolytic cleavage of EC JAM-C by neutrophil elastase (NE) drove this cascade of events as supported by presentation of NE to JAM-C via the neutrophil adhesion molecule Mac-1. The results identify local LTB4-NE axis as a promoter of neutrophil rTEM and provide evidence that this pathway can propagate a local sterile inflammatory response to become systemic.

Thromboelastometry and organ failure in trauma patients: a prospective cohort study.

INTRODUCTION: Data on the incidence of a hypercoagulable state in trauma, as measured by thromboelastometry (ROTEM), is limited and the prognostic value of hypercoagulability after trauma on outcome is unclear. We aimed to determine the incidence of hypercoagulability after trauma, and to assess whether early hypercoagulability has prognostic value on the occurrence of multiple organ failure (MOF) and mortality. METHODS: This was a prospective observational cohort study in trauma patients who met the highest trauma level team activation. Hypercoagulability was defined as a G value of ≥ 11.7 dynes/cm(2) and hypocoagulability as a G value of <5.0 dynes/cm(2). ROTEM was performed on admission and 24 hours later. RESULTS: A total of 1,010 patients were enrolled and 948 patients were analyzed. Median age was 38 (interquartile range (IQR) 26 to 53), 77% were male and median injury severity score was 13 (IQR 8 to 25). On admission, 7% of the patients were hypercoagulable and 8% were hypocoagulable. Altogether, 10% of patients showed hypercoagulability within the first 24 hours of trauma. Hypocoagulability, but not hypercoagulability, was associated with higher sequential organ failure assessment scores, indicating more severe MOF. Mortality in patients with hypercoagulability was 0%, compared to 7% in normocoagulable and 24% in hypocoagulable patients (P <0.001). EXTEM CT, alpha and G were predictors for occurrence of MOF and mortality. CONCLUSIONS: The incidence of a hypercoagulable state after trauma is 10% up to 24 hours after admission, which is broadly comparable to the rate of hypocoagulability. Further work in larger studies should define the clinical consequences of identifying hypercoagulability and a possible role for very early, targeted use of anticoagulants.

Hemostatic effects of fresh frozen plasma may be maximal at red cell ratios of 1:2.

BACKGROUND: Damage control resuscitation targets acute traumatic coagulopathy with the early administration of high-dose fresh frozen plasma (FFP). FFP is administered empirically and as a ratio with the number of packed red blood cells (PRBC). There is controversy over the optimal FFP:PRBC ratio with respect to outcomes, and their hemostatic effects have not been studied. We report preliminary findings on the effects of different FFP:PRBC ratios on coagulation. METHODS: This is a prospective observational cohort study of trauma patients requiring >4 U of PRBCs. Blood was drawn before and after each 4-U PRBC interval for prothrombin time and analysis by rotational thromboelastometry. Interval change in coagulation parameters were compared with the FFP:PRBC ratio received during each interval. RESULTS: Sixty 4-U PRBC intervals from 50 patients were available for analysis. All measures of coagulation deteriorated with low FFP:PRBC ratios (<1:2). Maximal hemostatic effect was observed in the 1:2 to 3:4 group: 12% decrease in prothrombin time (p=0.006), 56% decrease in clotting time (p=0.047), and 38% increase in maximum clot firmness (p=0.024). Transfusion with ≥1:1 ratio did not confer any additional improvement. There was a marked variability in response to FFP, and hemostatic function deteriorated in some patients exposed to 1:1 ratios. The beneficial effects of plasma were confined to patients with coagulopathy. CONCLUSIONS: Interim results from this prospective study suggest that FFP:PRBC ratios of ≥1:1 do not confer any additional advantage over ratios of 1:2 to 3:4. Hemostatic benefits of plasma therapy are limited to patients with coagulopathy.

Alternative method of oral dosing for rats.

Oral administration of drugs to laboratory rodents typically is achieved by using the gavage technique. Although highly effective, this method occasionally can cause esophageal injury as well as restraint-associated distress, particularly with repeated use. The aim of this study was to assess an alternative oral dosing method that could reduce the distress and morbidity associated with standard gavage techniques. The palatability and pharmacokinetic profile of 2 medicines approved for the treatment of Alzheimer disease, donepezil and galantamine, were investigated in male Lister hooded rats by using a syringe-feeding method and compared with results from traditional gavage administration. In addition, the stimulant nicotine was tested by using the syringe-feeding method in a separate series of experiments. Animals reliably learned to drink voluntarily from the syringe, and latency to drink decreased rapidly. The addition of donepezil, galantamine, or nicotine to sucrose had no apparent effect on the palatability of the solution, although nicotine produced aversive effects that inhibited subsequent voluntary intake. Oral bioavailability was improved by using syringe feeding with donepezil but not galantamine. Both drugs improved cognitive performance in the novel object recognition test, with similar behavioral profiles between the 2 methods of administration. Our results suggest that the syringe-feeding technique is an effective alternative oral dosing method in rats.

Preclinical investigations into the antipsychotic potential of the novel histamine H3 receptor antagonist GSK207040.

OBJECTIVES: To test the novel nonimidazole histamine H3 receptor antagonist 5-[(3-cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazapin-7-yl)oxy]-N-methyl-2-pyrazinecarboxamide (GSK207040) in a series of behavioral and neurochemical paradigms designed to evaluate its antipsychotic potential. MATERIALS AND METHODS: Acute orally administered GSK207040 was investigated for its capacity to reverse a 24-h-induced deficit in novel object recognition memory, deficits in prepulse inhibition (PPI) induced by isolation rearing, and hyperlocomotor activity induced by amphetamine. The acute neurochemical effects of GSK207040 were explored by analyzing rat anterior cingulate cortex microdialysates for levels of dopamine, noradrenaline, and acetylcholine and by c-fos immunohistochemistry. The potential for interaction with the antipsychotic dopamine D2 receptor antagonist haloperidol was explored behaviorally (spontaneous locomotor activity and catalepsy), biochemically (plasma prolactin), and via ex vivo receptor occupancy determinations. RESULTS: GSK207040 significantly enhanced object recognition memory (3 mg/kg) and attenuated isolation rearing-induced deficits in PPI (1.0 and 3.2 mg/kg) but did not reverse amphetamine-induced increases in locomotor activity. There was no evidence of an interaction of GSK207040 with haloperidol. GSK207040 (3.2 mg/kg) raised extracellular concentrations of dopamine, noradrenaline, and acetylcholine in the anterior cingulate cortex and c-fos expression in the core of the nucleus accumbens was increased at doses of 3.2 and 10.0 mg/kg. CONCLUSIONS: The behavioral and neurochemical profile of GSK207040 supports the potential of histamine H3 receptor antagonism to treat the cognitive and sensory gating deficits of schizophrenia. However, the failure of GSK207040 to reverse amphetamine-induced locomotor hyperactivity suggests that the therapeutic utility of histamine H(3) receptor antagonism versus positive symptoms is less likely, at least following acute administration.

Evaluation of the mGlu8 receptor as a putative therapeutic target in schizophrenia.

Aberrant glutamatergic neurotransmission may underlie the pathogenesis of schizophrenia and metabotropic glutamate receptors (mGluRs) have been implicated in the disease. We have established the localization of the group III mGluR subtype, mGluR8, in the human body and investigated the biological effects of the selective mGluR8 agonist (S)-3,4-dicarboxyphenylglycine ((S)-3,4-DCPG) in schizophrenia-related animal models. The mGlu8 receptor has a widespread CNS distribution with expression observed in key brain regions associated with schizophrenia pathogenesis including the hippocampus. (S)-3,4-DCPG inhibited synaptic transmission and increased paired-pulse facilitation in rat hippocampal slices supporting the role of mGluR8 as a presynaptic autoreceptor. Using the rat Maximal Electroshock Seizure Threshold (MEST) test, (S)-3,4-DCPG (30 mg/kg, i.p.) reduced seizure activity confirming the compound to be centrally active following systemic administration. (S)-3,4-DCPG did not reverse (locomotor) hyperactivity induced by acute administration of phenylcyclidine (PCP, 1-32 mg/kg, i.p.) or amphetamine (3-30 mg/kg, i.p.) in Sprague-Dawley rats. However, 10 nmol (i.c.v.) (S)-3.4-DCPG did reverse amphetamine-induced hyperactivity in mice although it also inhibited spontaneous locomotor activity at this dose. In addition, mGluR8 null mutant mouse behavioral phenotyping revealed an anxiety-related phenotype but no deficit in sensorimotor gating. These data provide a potential role for mGluR8 in anxiety and suggest that mGluR8 may not be a therapeutic target for schizophrenia.

Aripiprazole and its human metabolite are partial agonists at the human dopamine D2 receptor, but the rodent metabolite displays antagonist properties.

Aripiprazole is a novel antipsychotic drug, which displays partial agonist activity at the dopamine D(2) receptor. Aripiprazole has been extensively studied pre-clinically, both in vitro and in vivo, and these results have been correlated with clinical findings. However, aripiprazole is metabolised differently in rats and man and these metabolites may contribute to the profile of aripiprazole observed in vivo. We have therefore studied the interaction of aripiprazole and its principal rat and human metabolites in both in vitro models of dopamine hD(2) receptor function and affinity, and of in vivo models of dopamine rat D(2) receptor function. The human metabolite displayed similar levels of partial agonist activity to aripiprazole at the dopamine hD(2) receptor and displayed similar behavioural profile to aripiprazole in vivo, suggesting that in man the metabolite may maintain the effects of aripiprazole. In contrast, the rat metabolite displayed antagonist activity both in vitro and in vivo. Thus care must be taken in ascribing effects seen in vivo with aripiprazole in rats to dopamine D(2) receptor partial agonist activity in man, and that care must also be taken in extrapolating effects seen in rats to man, particularly from long-term studies.

Body weights and plasma prolactin levels in female rats treated subchronically with ziprasidone versus olanzapine.

In a putative animal model of antipsychotic drug-induced weight gain, female rats received either vehicle, ziprasidone (2.0, 6.0, 10 mg/kg) or olanzapine (2.0 mg/kg), orally, twice daily, for 7 days. Body weights were assessed daily and prolactin assayed at the end of the regimen. Ziprasidone caused significant weight gain, as did olanzapine, while stimulating distinct patterns of prolactin secretion. Thus, assessment of body weight provides only limited predictive validity in differentiating between weight gain-inducing and weight-neutral drugs.

Effects of the atypical antipsychotics olanzapine and risperidone on plasma prolactin levels in male rats: a comparison with clinical data.

RATIONALE: Hyperprolactinaemia is a common side effect of antipsychotic treatment and the clinical consequences associated with this, e.g. sexual dysfunction, can have a negative impact on patient compliance. OBJECTIVES: The aim of this study was to investigate the effect of the atypical antipsychotics olanzapine and risperidone on prolactin levels in rats using different treatment regimes and to compare these data with those reported clinically. METHODS: All experiments were carried out in male CD rats. In separate studies, the effects of acute, sub-chronic (7 days) and chronic (28 days) olanzapine and risperidone administration on prolactin levels were determined. Further studies investigated the time course of the prolactin response following olanzapine and risperidone treatment over 24 h. RESULTS: Both drugs significantly increased prolactin levels in a similar manner following acute administration, in keeping with clinically reported data. However, this elevation was still present following sub-chronic and chronic treatment, contrasting with clinical data with respect to olanzapine but not risperidone. Over 24 h, olanzapine demonstrated a more transient elevation of prolactin levels, whereas risperidone caused a robust and persistent increase in prolactin up to 24 h post-dose, closely mimicking clinical results. CONCLUSIONS: The present study has demonstrated that olanzapine and risperidone display similar effects on prolactin levels in the rat following acute and chronic administration but differ in their prolactin response over a 24-h period. In conclusion, prolactin levels in rats following atypical antipsychotic treatment may not be fully predictive of the clinical situation.

Characterisation of olanzapine-induced weight gain and effect of aripiprazole vs olanzapine on body weight and prolactin secretion in female rats.

RATIONALE: Atypical antipsychotic drug (APD)-induced weight gain causes non-compliance, increasing the risk of relapse and medical complications. OBJECTIVES: In an animal model, we assessed body weights, food intake, body fat/lean body mass contents and blood serum levels of glucose and lipids in female rats treated with olanzapine (Experiment 1). Also, we investigated the effect of aripiprazole vs olanzapine treatment on weight gain (WG) and plasma prolactin secretion in two strains (Wistar and Sprague-Dawley) and in two housing conditions (singly and group housed; Experiment 2). METHODS: In Experiment 1, Wistar females received either vehicle or olanzapine (5.0 mg kg(-1), p.o.) twice daily for 14 days. In Experiment 2, female rats (Wistar or Sprague-Dawley), housed singly or in groups, received either vehicle, aripiprazole (2.0-8.0 mg kg(-1), p.o.), or olanzapine (1.0-10 mg kg(-1), p.o.) twice daily for 7 days. Body weights and food intake were assessed daily. Body composition and blood assays were analyzed at the end of the treatment. RESULTS: WG induced by chronic olanzapine treatment was characterised by hyperphagia, increased body fat, and serum free fatty acid content and reduced lean tissue and serum glucose content. Subchronic aripiprazole treatment resulted in rapid and robust WG similar to those observed with olanzapine. In spite of similar effects on body weight, aripiprazole and olanzapine stimulated markedly different patterns of prolactin secretion. Body weight changes and prolactin secretion induced by these APDs were significantly modulated by housing and by strain. CONCLUSION: Assessment of body weight in the present model may not have predictive validity, and other measures may be needed to differentiate between WG-inducing and weight-neutral drugs.