Relationship between drug-induced movement disorders and psychosis in adults living in precarious housing or homelessness.

BACKGROUND: Studies have reported positive associations between drug-induced movement disorders (DIMDs) and symptoms of psychosis in patients with schizophrenia. However, it is not clear which subtypes of symptoms are related to each other, and whether one symptom precedes another. The current report assessed both concurrent and temporal associations between DIMDs and symptoms of psychosis in a community-based sample of homeless individuals. METHODS: Participants were recruited in Vancouver, Canada. Severity of DIMDs and psychosis was rated annually, allowing for the analysis of concurrent associations between DIMDs and Positive and Negative Syndrome Scale (PANSS) five factors. A brief version of the PANSS was rated monthly using five psychotic symptoms, allowing for the analysis of their temporal associations with DIMDs. Mixed-effects linear and logistic regression models were used to assess the associations. RESULTS: 401 participants were included, mean age of 40.7 years (SD = 11.2) and 77.4% male. DIMDs and symptoms of psychosis were differentially associated with each other, in which the presence of parkinsonism was associated with greater negative symptoms, dyskinesia with disorganized symptoms, and akathisia with excited symptoms. The presence of DIMDs of any type was not associated with depressive symptoms. Regarding temporal associations, preceding delusions and unusual thought content were associated with parkinsonism, whereas dyskinesia was associated with subsequent conceptual disorganization. CONCLUSIONS: The current study found significant associations between DIMDs and symptoms of psychosis in individuals living in precarious housing or homelessness. Moreover, there were temporal associations between parkinsonism and psychotic symptoms (delusions or unusual thought content), and the presence of dyskinesia was temporally associated with higher odds of clinically relevant conceptual disorganization.

Developing prediction models for symptom severity around the time of discharge from a tertiary-care program for treatment-resistant psychosis.

Antipsychotics are the only therapeutic class indicated in the symptomatic management of psychotic disorders. However, individuals diagnosed with schizophrenia or schizoaffective disorder may not always benefit from these first-line agents. This refractoriness to conventional treatment can be difficult to address in most clinical settings. Therefore, a referral to a tertiary-care program that is better able to deliver specialized care in excess of the needs of most individuals may be necessary. The average outcome following a period of treatment at these programs tends to be one of improvement. Nonetheless, accurate prognostication of individual-level responses may be useful in identifying those who are unlikely to improve despite receiving specialized care. Thus, the main objective of this study was to predict symptom severity around the time of discharge from the Refractory Psychosis Program in British Columbia, Canada using only clinicodemographic information and prescription drug data available at the time of admission. To this end, a different boosted beta regression model was trained to predict the total score on each of the five factors of the Positive and Negative Syndrome Scale (PANSS) using a data set composed of 320 hospital admissions. Internal validation of these prediction models was then accomplished by nested cross-validation. Insofar as it is possible to make comparisons of model performance across different outcomes, the correlation between predictions and observations tended to be higher for the negative and disorganized factors than the positive, excited, and depressed factors on internal validation. Past scores had the greatest effect on the prediction of future scores across all 5 factors. The results of this study serve as a proof of concept for the prediction of symptom severity using this specific approach.

Movement disorders associated with substance use in adults living in precarious housing or homelessness.

OBJECTIVE: Many individuals living in precarious housing or homelessness have multimorbid illnesses, including substance use, psychiatric, and neurological disorders. Movement disorders (MDs) associated substance use are amongst the poorly studied subtopics of drug-induced MDs. The aim of the present study was, therefore, to determine the proportion affected and severity of different signs of MDs, as well as their associations with substance use in a community-based sample of precariously housed and homeless individuals. METHODS: Participants were recruited from an impoverished urban neighborhood and were assessed for substance dependence and self-reported substance use (alcohol, cannabis, cocaine, methamphetamine, nicotine, and opioids), as well as for the severity of signs of MDs (akathisia, dyskinesia, dystonia, and parkinsonism). Adjusted regression models were used to estimate the associations of the severity of signs with the frequency of substance use over the past 4 weeks and with the baseline diagnosis of substance dependence. RESULTS: The proportion of the sample with clinically relevant signs of MDs in any of the four categories was 18.6% (n = 401), and these participants demonstrated lower levels of functioning than those without signs. Of the different types of substance use, only methamphetamine (its frequency of use and dependence) was significantly associated with greater severity of overall signs of MDs. Frequency of methamphetamine use significantly interacted with age and sex, whereby older female participants exhibited the greatest overall severity with increased methamphetamine use. Of the different signs of MDs, methamphetamine use frequency was positively associated with the severity of trunk/limb dyskinesia and hypokinetic parkinsonism. Relative to no use, concurrent use of antipsychotics demonstrated lower severity of trunk/limb dyskinesia and greater severity of hypokinetic parkinsonism with methamphetamine use, and greater severity of dystonia with cocaine use. CONCLUSIONS: Our study found a high proportion of MDs in a relatively young sample, and their severity was consistently associated with methamphetamine use, moderated by participant demographics and antipsychotic use. These disabling sequelae represent an important and understudied neurological condition that may affect quality of life and will require further study.

The safety of high-dose dexmedetomidine after cardiac surgery: a historical cohort study.

PURPOSE: The off-label use of dexmedetomidine beyond the monograph-recommended maximum dose of 0.7 µg·kg-1·hr-1 is common in postoperative cardiac surgical units; however, limited data exist on the association of higher doses and adverse hemodynamic effects. We sought to compare the rate of hypotension or bradycardia in cardiac surgery patients receiving peak infusion doses below and above 0.7 µg·kg-1·hr-1 for any indication or duration. METHODS: In this historical cohort study, we reviewed all patients who received dexmedetomidine infusion after cardiac surgery between June 2013 and July 2017 at a single centre. Regardless of the duration of exposure at the peak infusion dose, patients were categorized into high- or standard-dose groups using 0.7 µg·kg-1·hr-1 as the cutoff value. We compared rates of the primary composite outcome of hypotension or bradycardia, and secondary outcomes (i.e., arrhythmia and hyperglycemia) between groups using the two-proportion z test. Exploratory regression models were fitted to adjust for potential confounders. RESULTS: The median [interquartile range (IQR)] peak infusion dose was 1.0 [1.0-1.4] µg·kg-1·hr-1 in the high-dose group (N = 121) and 0.5 [0.4-0.7] µg·kg-1·hr-1 in the standard-dose group (N = 124). The rates of the primary composite outcome were 73% and 65%, respectively (absolute risk difference, 8%; 95% confidence interval, -3 to 20; P = 0.17). There was no significant difference in primary or secondary outcomes between groups. CONCLUSION: There was a high overall rate of hypotension or bradycardia in patients receiving dexmedetomidine after cardiac surgery; infusion rates below or above 0.7 µg·kg-1·hr-1 had similar rates of adverse hemodynamic events.

RéSUMé: OBJECTIF: L'utilisation non conforme (off-label) de la dexmédétomidine au-delà de la dose maximale recommandée dans la monographie de 0,7 µg·kg−1·h−1 est fréquente dans les unités de chirurgie cardiaque postopératoire; cependant, il n'existe que peu de données sur l'association entre des doses plus élevées et des effets hémodynamiques indésirables. Nous avons cherché à comparer le taux d'hypotension ou de bradycardie chez les patients de chirurgie cardiaque recevant des doses de perfusion maximales inférieures ou supérieures à 0,7 µg·kg−1·h−1 pour toute indication ou durée. MéTHODE: Dans cette étude de cohorte historique, nous avons passé en revue tous les patients qui ont reçu une perfusion de dexmédétomidine après une chirurgie cardiaque entre juin 2013 et juillet 2017 dans un seul centre. Quelle que soit la durée de l'exposition à la dose de perfusion maximale, les patients ont été classés en groupes à dose élevée ou standard selon une valeur seuil de 0,7 µg·kg−1·h−1. Nous avons comparé les taux d'hypotension ou de bradycardie, notre critère d'évaluation principal composite, et les taux des critères d'évaluation secondaires (soit l'arythmie et l'hyperglycémie) entre les groupes à l'aide du test z à deux proportions. Des modèles de régression exploratoire ont été ajustés pour tenir compte des facteurs de confusion potentiels. RéSULTATS: La dose de perfusion maximale médiane [écart interquartile (ÉIQ)] était de 1,0 [1,0­1,4] µg·kg−1·h−1 dans le groupe à forte dose (n = 121) et de 0,5 [0,4­0,7] µg·kg−1·h−1 dans le groupe à dose standard (n = 124). Les taux pour le critère d'évaluation principal composite étaient de 73% et 65%, respectivement (différence de risque absolue, 8%; intervalle de confiance à 95%, -3 à 20; P = 0,17). Aucune différence intergroupe significative n'a été observée dans les critères d'évaluation primaires ou secondaires. CONCLUSION: Nous avons observé un taux global élevé d'hypotension ou de bradycardie chez les patients recevant de la dexmédétomidine après une chirurgie cardiaque; les taux de perfusion inférieurs ou supérieurs à 0,7 µg·kg−1·h−1 ont entraîné des taux similaires d'événements hémodynamiques indésirables.

Antipsychotic prescribing patterns on admission to and at discharge from a tertiary care program for treatment-resistant psychosis.

Retrospective data were collected from 330 individuals who were treated at a tertiary care program for treatment-resistant psychosis between 1994 and 2010. The main objectives were to compare the use of antipsychotic monotherapy to polypharmacy and to characterize within-individual changes in treatment and symptomatology between admission and discharge. At admission, individuals who were prescribed only one antipsychotic were comparable to those who were prescribed at least two antipsychotics with regard to demographics and symptom severity. The use of psychotropic medications other than antipsychotics was also similar between the two groups. However, the magnitude of antipsychotic utilization was greater in individuals who were receiving antipsychotic polypharmacy. In addition, a greater proportion received excessive doses at admission. Similar findings were observed when the two antipsychotic prescribing practices were compared at discharge. Three important patterns were identified when investigating within-individual changes. First, fewer individuals were prescribed more than one antipsychotic at discharge. This was accompanied by a general decrease in the magnitude of antipsychotic utilization. Second, the number of individuals who were prescribed clozapine had increased by discharge. Most who were already prescribed clozapine at admission had their doses increased. Third, improvements in symptomatology were observed across all of the subscales included in the Positive and Negative Symptom Scale (PANSS); 57.9% of individuals experienced a relative reduction in total PANSS scores exceeding 20%. Based on these findings, it is possible to alleviate symptom severity while reducing antipsychotic utilization when patients are treated at a tertiary care program for treatment-resistant psychosis.

Proposing the Use of Partial AUC as an Adjunctive Measure in Establishing Bioequivalence Between Deltoid and Gluteal Administration of Long-Acting Injectable Antipsychotics.

The maximum plasma concentration (C max) and the area under the plasma concentration-time curve (AUC) are commonly used to establish bioequivalence between two formulations of the same oral medication. Similarly, these pharmacokinetic parameters have also been used to establish bioequivalence between two sites of administration for the same injectable formulation. However, these conventional methods of establishing bioequivalence are of limited use when comparing modified-release formulations of a drug, particularly those with rates of absorption that are amenable to change with the site of injection. Inherent differences in the rate of absorption can result in clinically significant differences in early exposure and drug response. Here, we propose the use of the partial AUC (pAUC) as a measure of early exposure to aid in the assessment of bioequivalence between the gluteal and the deltoid site of administration for long-acting injectable antipsychotics.

The Pharmacokinetics of Second-Generation Long-Acting Injectable Antipsychotics: Limitations of Monograph Values.

Product monographs (also known by terms such as Summary of Product Characteristics and Highlights of Prescribing Information, depending on the jurisdiction) provide essential information to ensure the safe and effective use of a drug. Medical practitioners often rely on these monographs for guidance on matters related to pharmacokinetics as well as indications, contraindications, clinical pharmacology, and adverse reactions. The clinical and scientific information found within these documents, forming the basis for decision making, are presumed to be derived from well-designed studies. The objective of this review is to examine the source and validity of the pharmacokinetic data used in establishing the half-lives and times to steady-state reported in the product monographs of second-generation long-acting injectable antipsychotics. Thus, we have critically evaluated the clinical trials from which the pharmacokinetic parameters listed in the product monographs were determined. In many cases, the pharmacokinetic information presented in product monographs is of limited use to clinicians wishing to optimize the effectiveness and tolerability of second-generation long-acting injectable antipsychotics. Under such circumstances, off-label prescribing practices may actually produce better clinical outcomes than if decisions were made based on the product monographs alone.

A retrospective study of antipsychotic drug switching in a pediatric population.

BACKGROUND: Antipsychotic drugs can be used to help treat a wide variety of psychiatric disorders. However, specific antipsychotic drugs for any particular patient may need to be changed for a number of different reasons, including a lack of therapeutic efficacy and / or intolerance to medication side-effects. Drug switching may occur through a limited number of established patterns. The nature of these changes is not well characterized in youth, despite their frequent occurrence. METHODS: A retrospective analysis of antipsychotic drug switches was conducted on patients who had been admitted as inpatients to a tertiary care child and adolescent psychiatric institute. PharmaNet (a large, central administrative database) records of all medications prescribed in the 52 weeks prior to admission, and then between admission and discharge, were analyzed for switching patterns. Additional data regarding diagnoses were obtained from medical chart review. RESULTS: Patients represented a diagnostically heterogeneous population, and almost all antipsychotic drugs were administered off-label. In the one year prior to and during admission to the hospital, a total of 31 out of 139 patients switched antipsychotic drugs. The frequency of switching increased closer to the time of admission, and the proportional rate of switching was even higher during hospital stay. The most common switch was from risperidone to quetiapine. Our analysis identified three main patterns of drug switching, all occurring with similar frequency: titrated drug switches, abrupt drug switches and concurrent drug administration. CONCLUSIONS: The present study indicates that antipsychotic drug switching in youth may be relatively common, particularly in the year prior to hospitalization. No specific manner of drug switching predominates. This study also demonstrates the feasibility of using large administrative databases to characterise switching patterns in youth.