Severe parkinsonism under treatment with antipsychotic drugs

Drug-induced parkinsonism: diagnosis and treatment

INTRODUCTION

Drug-induced parkinsonism (DIP) is one of the most common iatrogenic movement disorders. It is characterized by tremors, slowness of movement, and shuffling gait with postural instability, clinically indistinguishable from idiopathic Parkinson's disease. Prior exposure to antipsychotic medications or other dopamine receptor blocking agents (DRBAs) is required for the diagnosis.

AREAS COVERED

This article aims to review the epidemiology, pathophysiology, clinical features, ancillary testing, and treatment of DIP. A literature search was undertaken in PubMed from January 2013 to January 2024.

EXPERT OPINION

A clinician's suspicion of DIP must always be present when a patient develops acute to subacute onset of parkinsonism while taking a DRBA. As DIP can be indistinguishable from idiopathic PD, ancillary testing, such as DaTscans and skin biopsy searching for alpha-synuclein deposits, are often required to make a definitive diagnosis. When DIP develops, steps should be made to discontinue the offending agent or, in the case of antipsychotics, dose reduction or change to an agent with lower risk for DIP, such as quetiapine or clozapine. Prophylactic treatment with anticholinergics is not indicated.

Outcome of Drug-Induced Parkinsonism in the Elderly: A Permanent Nonprogressive Parkinsonian Syndrome May Occur Following Discontinuation of Cinnarizine and Flunarizine

Parkinsonism induced by dopamine receptor antagonists, traditionally considered completely reversible following offending drug withdrawal, may unmask a degenerative parkinsonism in the patients with an underlying subclinical disease. In elderly patients, parkinsonism induced by the calcium channel blockers such as piperazine derivates cinnarizine and flunarizine may persist following drug discontinuation resulting in a permanent nonprogressive syndrome fulfilling the criteria for tardive parkinsonism. Whether this outcome occurs also following exposure to dopamine receptor antagonists such as neuroleptics and benzamide derivates or represents a class effect of the voltage-gated L-type calcium channel blockers, such as cinnarizine and flunarizine, due to their complex pharmacodynamic properties remains to be established.

Acute Antipsychotic Use and Presence of Dysphagia Among Older Veterans with Heart Failure

OBJECTIVE

Examine whether new antipsychotic (AP) exposure is associated with dysphagia in hospitalized patients with heart failure (HF).

DESIGN

Retrospective cohort.

SETTINGS AND PARTICIPANTS

AP-naïve Veterans hospitalized with HF and subsequently discharged to a skilled nursing facility (SNF) between October 1, 2010, and November 30, 2019.

METHODS

We linked Veterans Health Administration (VHA) electronic medical records with Centers for Medicare & Medicaid (CMS) Minimum Data Set (MDS) version 3.0 assessments and CMS claims. The exposure variable was administration of ≥1 dose of a typical or atypical AP during hospitalization. Our main outcome measure was dysphagia presence defined by (1) inpatient dysphagia diagnosis codes and (2) the SNF admission MDS 3.0 swallowing-related items to examine post-acute care dysphagia status. Inverse probability of treatment weighting was used for risk adjustment.

RESULTS

The analytic cohort consisted of 29,591 Veterans (mean age 78.5 ± 10.0 years; female 2.9%; n = 865). Acute APs were administered to 9.9% (n = 2941). Those receiving APs had differences in prior dementia [37.1%, n = 1091, vs 22.3%, n = 5942; standardized mean difference (SMD) = 0.33] and hospital delirium diagnoses (7.7%, n = 227 vs 2.8%, n = 754; SMD = 0.22). Acute AP exposure was associated with nearly double the risk for hospital dysphagia diagnosis codes [adjusted (adj.) relative risk (RR) 1.9, 95% CI 1.8, 2.1]. At the SNF admission MDS assessment, acute AP administration during hospitalization was associated with an increased dysphagia risk (adj. RR 1.2, 95% CI 1.0, 1.5) both in the oral (adj. RR 1.7, 95% CI 1.2, 2.0) and pharyngeal phases (adj. RR 1.3, 95% CI 1.0, 1.7).

CONCLUSIONS AND IMPLICATIONS

In this retrospective study, AP medication exposure was associated with increased dysphagia coding and MDS assessment. Considering other adverse effects, acute AP should be cautiously administered during hospitalization, particularly in those with dementia. Swallowing function is critical to hydration, nutrition, and medical management of HF; therefore, when acute APs are initiated, a swallow evaluation should be considered.

Risk factors, clinical correlates, and social functions of Chinese schizophrenia patients with drug-induced parkinsonism: A cross-sectional analysis of a multicenter, observational, real-world, prospective cohort study

Background: Drug-induced parkinsonism (DIP) is the most prevalent neurological side effect of antipsychotics in the Chinese population. Early prevention, recognition, and treatment of DIP are important for the improvement of treatment outcomes and medication adherence of schizophrenia patients. However, the risk factors of DIP and the impact on the clinical syndromes of schizophrenia remain unknown. Aim: The goal of this study was to explore the risk factors, clinical correlates, and social functions of DIP in Chinese schizophrenia patients. Methods: A cross-sectional analysis of a multicenter, observational, real-world, prospective cohort study of the Chinese schizophrenia population with a baseline assessment was conducted from the year 2012 to 2018. Participants were recruited from four mental health centers in Shanghai and totaled 969 subjects. Sociodemographic data, drug treatment, and clinical variables were compared between the DIP group and the non-DIP group. Variables that correlated with the induction of DIP, and with p≤ 0.1, were included in the binary logistic model for analyzing the risk factors of DIP. First generation antipsychotics (FGA)/second generation antipsychotics (SGA) model and high and low/medium D2 receptor antipsychotics were analyzed respectively to control the bias of co-linearity. All risk factors derived from the a forementioned models and clinical variables with p≤ 0.1 were included in the multivariate analysis of clinical correlates and social function of DIP patients. The Positive and Negative Syndrome Scale (PANSS) model and the personal and social performance (PSP) model were analyzed separately to control for co-linearity bias. Results: Age (OR = 1.03, p< 0.001), high D2 receptor antagonist antipsychotic dose (OR = 1.08, p = 0.032), and valproate dose (OR = 1.01, p = 0.001) were the risk factors of DIP. FGA doses were not a significant contributor to the induction of DIP. Psychiatric symptoms, including more severe negative symptoms (OR = 1.09, p< 0.001), lower cognition status (OR = 1.08, p = 0.033), and lower excited symptoms (OR = 0.91, p = 0.002), were significantly correlated with DIP induction. Social dysfunction, including reduction in socially useful activities (OR = 1.27, p = 0.004), lower self-care capabilities (OR = 1.53, p< 0.001), and milder disturbing and aggressive behavior (OR = 0.65, p< 0.001), were significantly correlated with induction of DIP. Valproate dose was significantly correlated with social dysfunction (OR = 1.01, p = 0.001) and psychiatric symptoms (OR = 1.01, p = 0.004) of DIP patients. Age may be a profound factor that affects not only the induction of DIP but also the severity of psychiatric symptoms (OR = 1.02, p< 0.001) and social functions (OR = 1.02, p< 0.001) of schizophrenia patients with DIP. Conclusion: Age, high D2 receptor antagonist antipsychotic dose, and valproate dose are risk factors for DIP, and DIP is significantly correlated with psychiatric symptoms and social performance of Chinese schizophrenia patients. The rational application or discontinuation of valproate is necessary. Old age is related to psychotic symptoms and social adaption in Chinese schizophrenic patients, and early intervention and treatment of DIP can improve the prognosis and social performance of schizophrenia patients. Clinical Trial Registration: Identifier: NCT02640911.

SLC6A3, HTR2C and HTR6 Gene Polymorphisms and the Risk of Haloperidol-Induced Parkinsonism

Antipsychotic-induced parkinsonism (AIP) is the most common type of extrapyramidal side effect (EPS), caused by the blockage of dopamine receptors. Since dopamine availability might influence the AIP risk, the dopamine transporter (DAT) and serotonin receptors (5-HTRs), which modulate the dopamine release, may be also involved in the AIP development. As some of the individual differences in the susceptibility to AIP might be due to the genetic background, this study aimed to examine the associations of SLC6A3, HTR2C and HTR6 gene polymorphisms with AIP in haloperidol-treated schizophrenia patients. The Extrapyramidal Symptom Rating Scale (ESRS) was used to evaluate AIP as a separate entity. Genotyping was performed using a PCR, following the extraction of blood DNA. The results revealed significant associations between HTR6 rs1805054 polymorphism and haloperidol-induced tremor and rigidity. Additionally, the findings indicated a combined effect of HTR6 T and SLC6A3 9R alleles on AIP, with their combination associated with significantly lower scores of ESRS subscale II for parkinsonism, ESRS-based tremor or hyperkinesia and ESRS subscales VI and VIII. These genetic predictors of AIP could be helpful in better understanding its pathophysiology, recognizing the individuals at risk of developing AIP and offering personalized therapeutic strategies for the patients suffering from this EPS.

MK212, a 5-hydroxytryptamine 2C receptor agonist, reverses prepulse inhibition deficits in the medial prefrontal cortex and ventral hippocampus

Prepulse inhibition (PPI) is disrupted in many neuropsychiatric diseases. Molecules such as 5-HT_2C receptor agonists alleviate PPI deficits in rodents; however, the precise mechanisms and critical regions of the brain responsible for the reversal effect of these agonists remain inconclusive. The present study aimed to investigate the areas of the brain critical for the reversal effect of 5-HT_2C receptor agonists on PPI deficits in mice. The results showed that systemic administration of the 5-HT_2C receptor agonist MK212 did not affect normal PPI behavior, but reversed the PPI deficits induced by the N-methyl d-aspartate receptor antagonist MK801 in mice. In addition, the 5-HT_2C receptor antagonist SB242084 had no effect on PPI behavior despite MK801 treatment. Moreover, local infusion of MK212 into the medial prefrontal cortex and ventral hippocampus, excluding the nucleus accumbens or ventral tegmental area, rescued the PPI deficits induced by MK801. These data suggest that the medial prefrontal cortex and ventral hippocampus are critical brain areas responsible for the reversal of 5-HT_2C agonists on PPI deficits. The results will contribute to our current knowledge on the molecular and neural mechanisms underlying the antipsychotic effects of 5-HT_2C receptor agonists, especially the neural circuits modulated by 5-HT_2C receptor activity.

Atypical dyskinesias under treatment with antipsychotic drugs: Report from the AMSP multicenter drug safety project

OBJECTIVES

The aim of this study was to describe atypical dyskinesias (AtypDs) occurring during treatment with antipsychotic drugs (APDs). AtypDs are dyskinesias showing either an unusual temporal relationship between onset of treatment and start of the adverse drug reaction (ADR) or an unusual presentation of clinical symptoms.

METHODS

Data on the utilisation of APDs and reports of severe APD-induced AtypDs were collected using data from the observational pharmacovigilance programme - 'Arzneimittelsicherheit in der Psychiatrie (English: drug safety in psychiatry)' (AMSP) - from 1993 to 2016.

RESULTS

A total of 495,615 patients were monitored, of which 333,175 were treated with APDs. Sixty-seven cases (0.020%) of severe AtypDs under treatment with APDs were registered. The diagnoses of schizophrenic disorders as well as organic mental disorders were related to significantly higher rates of AtypDs. Second-generation antipsychotic drugs (SGAs) showed slightly higher rates of AtypDs (0.024%) than high-potency (0.011%) or low-potency first-generation antipsychotic drugs (FGAs; 0.006%). In 41 cases (61.2%), two or more drugs were found to cause AtypDs.

CONCLUSIONS

Our study indicates that AtypDs are rare ADRs. SGAs may have a higher risk for the occurrence of AtypDs than FGAs. Clinicians should be aware of this ADR and patients should be monitored and examined carefully.

Recognition and Management of Antipsychotic-Induced Parkinsonism in Older Adults: A Narrative Review

Background: Parkinsonism is a common side-effect of antipsychotic drugs especially in older adults, who also present with a higher frequency of neurodegenerative disorders like Idiopathic Parkinson’s disease (IPD). Distinguishing between antipsychotic-induced parkinsonism (AIP) and IPD is challenging due to clinical similarities. Up to 20% of older adults may suffer from persisting parkinsonism months after discontinuation of antipsychotics, suggesting underlying neurodegeneration. A review of the literature on AIP in older adults is presented, focusing on epidemiology, clinical aspects, and management. Methods: A literature search was undertaken on EMBASE, MEDLINE and PsycINFO, for articles on parkinsonism induced by antipsychotic drugs or other dopamine 2 receptor antagonists in subjects aged 65 or older. Results: AIP in older adults is the second most common cause of parkinsonism after IPD. Older age, female gender, exposure to high-potency first generation antipsychotics, and antipsychotic dosage are the main risk factors. The clinical presentation of AIP resembles that of IPD, but is more symmetrical, affects upper limbs more, and tends to have associated motor phenomena such as orofacial dyskinesias and akathisia. Presence of olfactory dysfunction in AIP suggests neurodegeneration. Imaging of striatal dopamine transporters is widely used in IPD diagnosis and could help to distinguish it from AIP. There is little evidence base for recommending pharmacological interventions for AIP, the best options being dose-reduction/withdrawal, or switching to a second-generation drug. Conclusions: AIP is a common occurrence in older adults and it is possible to differentiate it from IPD. Further research is needed into its pathophysiology and on its treatment.