Drug-induced parkinsonism: a review

Evaluation and Management of Tremor

Tremor is a commonly encountered condition in the primary care setting and can manifest at rest, with action, or both. Common causes include Parkinson disease, essential tremor, and drug-induced tremor. In this article, the authors discuss how to examine a patient with tremor and which features of the history and examination can help clue the provider in to the appropriate diagnosis. They also review treatments for varying types of tremor and when referral to a neurologist may be necessary.

Anatomy, physiology, and evaluation: Bowel, bladder, and sexual disorders

Our present understanding of bowel and bladder control has changed dramatically with the introduction of functional imagining technologies such as PET, SPECT, fMRI scanning, and near-infrared spectroscopy of the brain. Urologists tend to see control of urination and defecation as processes that occurred at or below the level of the pons for the most part. In this chapter, we examine the control of storing and emptying of urine and stool from what will be a more neurocentric perspective, integrating the frontal lobes into the process and moving beyond the pons on which most of the literature has focused in the past. Utilizing this approach gives us a better understanding of why there is an overlapping of neuropsychiatric problems in many patients with voiding dysfunction.

Updated Perspectives on the Management of Drug-Induced Parkinsonism (DIP): Insights from the Clinic

Parkinsonism refers to the clinical combination of bradykinesia, rigidity, tremor, and postural instability. Parkinsonism is often neurodegenerative, but it can be secondary or iatrogenic, as in drug-induced parkinsonism (DIP), which is the topic of this review. We review the pathophysiology of DIP, differentiate DIP and idiopathic Parkinson's disease (PD), list culprit medications in the development of DIP, discuss the diagnosis of DIP as well as the motor and nonmotor signs and symptoms that can help with differentiation of DIP and PD, and detail the management of DIP.

Doxorubicin induced aggregation of α-synuclein: Insights into the mechanism of drug induced Parkinsonism

The aggregation of α-synuclein is a prominent feature of Parkinson's disease. It is induced by factors such as genetic mutations and presence of metal salts leading to Parkinson's like symptoms. Existing case studies show that patients undergoing cancer chemotherapeutics are also prone to developing Parkinson's like symptoms. However, the underlying cause behind onset of these symptoms is not understood. It is not clear whether the administration of chemotherapeutic drugs alter the structural stability of α-synuclein. In the present study, we address this question by looking into the effect of chemotherapeutic drug namely doxorubicin on the α-synuclein stability. Using complementary spectroscopic, molecular docking and imaging techniques, we observe that doxorubicin interacted with central aggregation prone region of α-synuclein and induces destabilization leading to aggregation. We also show that the combination of doxorubicin and L-DOPA drugs impedes the α-synuclein aggregation. This may explain the reason behind the effectiveness of using L-DOPA against Parkinson's like symptoms.

Respecting the Patient's Choice: A Case of Possible Drug-Induced Parkinsonism

This report describes a case of likely drug-induced Parkinsonism (DIP) identified by the pharmacist. A 54-year-old female patient was referred by a physician to the pharmacist in a rural, integrated care team for a comprehensive medication review (CMR) to address the patient's concerns of possible Parkinson's disease (PD). While PD may occur over the progression of age, medications that affect dopamine transport can also cause DIP, a secondary form of Parkinson's disease. Although PD and DIP may be clinically indistinguishable, differentiation may be possible by reviewing a patient's medication history for any potential causative drugs correlating to the timeline of the onset of symptoms. In this case, the pharmacist reviewed the medication profile and identified medications that could be responsible for causing DIP, specifically bupropion. The pharmacist suggested discontinuing bupropion and identifying another option for treating depression. The patient appreciated the suggestion and education, but ultimately preferred continuing her bupropion therapy instead of discontinuing therapy or changing to an alternative agent. At a follow-up meeting with the pharmacist, not only was the patient still experiencing tremors despite taking carbidopa/levodopa, but additional medications known to be potential inducers of tremors were added to her regimen. Although the pharmacist repeatedly discussed DIP with the patient and believed stopping bupropion would determine whether her Parkinsonism was PD or DIP, ultimately the patient continued taking bupropion because of concerns related to depression severity and the impact on her well-being. The patient's wishes were respected.

Efficacy of Xiang-Sha-Liu-Jun-Zi on chemotherapy-induced nausea and vomiting: A protocol for systematic review and meta-analysis

BACKGROUND

Cancer is the main cause of death worldwide, and chemotherapy is the basic method of treating cancer. However, chemotherapy-induced nausea and vomiting (CINV) is the most common side effect of chemotherapy, and conventional antiemetics for the treatment of CINV also have side effects. At present, a large number of randomized controlled trials have shown that Xiang-Sha-Liu-Jun-Zi (XSLJZ) can effectively treat CINV, but there is no systematic review. Therefore, this systematic review aims to discuss the effectiveness of XSLJZ in the treatment of CINV.

METHODS

Search for relevant documents in the Chinese and English databases, and the search time is limited to March 2021. Databases include Embase, Cochrane Library, Web of Science, PubMed, China National Knowledge Infrastructure, Chongqing VIP Information Resource Integration Service Platform, Wanfang Data, Chinese Biomedical Literature, etc. We will search the international clinical trial registration platform and the Chinese clinical trial registration platform to find ongoing and unpublished clinical trials. Randomized controlled trial of the efficacy of XSLJZ in the treatment of CINV were collected. After screening the literature according to the inclusion and exclusion criteria, two researchers independently extracted the data. The effective rate of treatment is the main outcome indicator of this study. The secondary indicators of this study include the incidence of adverse reactions and the improvement rate of quality of life. RevMan 5.3.5 software was used for statistical analysis. Grades of Recommendation, Assessment, Development, and Evaluation system will be used to evaluate the quality evidence for each outcome.

RESULTS

This study will provide the latest evidence for the treatment of CINV by XSLJZ.

CONCLUSION

: To evaluate the efficacy of XSLJZ in the treatment of CINV.

UNIQUE INPLASY NUMBER

INPLASY202140079.

Movement disorders induced by psychiatric drugs that do not block dopamine receptors

Most movement disorders in psychiatric patients are induced by neuroleptic antipsychotic medications, all of which are dopamine D2 receptor blocking drugs. These include: acute onset disorders: dystonic reactions, akathisia and the neuroleptic malignant syndrome (NMS); non-acute onset parkinsonism; and the tardive syndromes. However, many other medications, when used at recommended doses, also induce movement disorders, with tremor being the most common. With the exception of serotonin syndrome, they are rarely as severe or disabling as the neuroleptic extrapyramidal syndromes may be. The serotonin reuptake inhibiting (SSRI) drugs are associated with the serotonin syndrome, a life-threatening disorder, but may also cause tremor and akathisia. While SSRI's have been thought to occasionally cause a tardive dyskinesia-like syndrome, this almost never occurs without prior or concurrent neuroleptic exposure as well. There also are few reliable data to support an association between antidepressants and parkinsonism. Valproic acid has been shown to cause parkinsonism, and lithium may as well, in addition to both having the well-known side effect of tremors. Myoclonus and asterixis are usually induced by toxic levels of medications but may appear with therapeutic levels, particularly with anticonvulsant mood stabilizers, and clozapine. Ataxia rarely occurs with non-toxic levels of drug, particularly anticonvulsants, benzodiazepines and lithium.

Drug-induced parkinsonism: Revisiting the epidemiology using the WHO pharmacovigilance database

INTRODUCTION

Drug-Induced Parkinsonism (DIP) is the second most common cause of parkinsonism after idiopathic Parkinson's disease. Little is known about DIP epidemiology. Using VigiBase®, the objective of this study was to assess the main characteristics of DIP reporting around the world.

METHODS

We described reports recorded in the WHO pharmacovigilance database, Vigibase® and classified as "Parkinsonism" between 2000 and 2017. Differences of reporting between geographical locations and characteristics of reports were investigated using disproportionality analysis with calculation of Reporting Odds Ratios (ROR) and its 95% confidence interval.

RESULTS

Among the 9,009,107 reports recorded in VigiBase®, 4565 (0.05%) were DIP. Co reported terms were mainly "tremor" (n = 408, 8.9%), "gait disturbance" (n = 209, 4.6%) and "extrapyramidal disorders" (n = 180, 3.9%). DIP reports were significantly more frequent in men (ROR = 1.4; 95% CI 1.3-1.5) and in patients aged 75 and over (ROR = 2.12; 95% CI 1.98-2.26). Compared to all other continents, risk of reporting drug-induced parkinsonism was higher in Europe (ROR = 2.89; 95% CI 2.73-3.07), Africa (ROR = 1.81; 95% CI 1.46-2.25) and Oceania (ROR = 1.50; 95% CI 1.27-1.77). The risk was lower in Asia (ROR = 0.55; 95% CI 0.51-0.59) and America (ROR = 0.55 95% CI 0.51-0.59). The highest risk of DIP reporting was found with sulpiride and haloperidol followed by risperidone, aripiprazole, paliperidone, metoclopramide, olanzapine, quetiapine and clozapine.

CONCLUSION

Risk of DIP reports was higher in men, in people aged 75 and over and in Europe. Main drugs involved are antipsychotics not only drugs from the first generation but also those from the second one.

Receptor Ligands as Helping Hands to L-DOPA in the Treatment of Parkinson's Disease

Levodopa (LD) is the most effective drug in the treatment of Parkinson’s disease (PD). However, although it represents the “gold standard” of PD therapy, LD can cause side effects, including gastrointestinal and cardiovascular symptoms as well as transient elevated liver enzyme levels. Moreover, LD therapy leads to LD-induced dyskinesia (LID), a disabling motor complication that represents a major challenge for the clinical neurologist. Due to the many limitations associated with LD therapeutic use, other dopaminergic and non-dopaminergic drugs are being developed to optimize the treatment response. This review focuses on recent investigations about non-dopaminergic central nervous system (CNS) receptor ligands that have been identified to have therapeutic potential for the treatment of motor and non-motor symptoms of PD. In a different way, such agents may contribute to extending LD response and/or ameliorate LD-induced side effects.

Diametric neural ensemble dynamics in parkinsonian and dyskinetic states

Loss of dopamine in Parkinson's disease is hypothesized to impede movement by inducing hypo- and hyperactivity in striatal spiny projection neurons (SPNs) of the direct (dSPNs) and indirect (iSPNs) pathways in the basal ganglia, respectively. The opposite imbalance might underlie hyperkinetic abnormalities, such as dyskinesia caused by treatment of Parkinson's disease with the dopamine precursor L-DOPA. Here we monitored thousands of SPNs in behaving mice, before and after dopamine depletion and during L-DOPA-induced dyskinesia. Normally, intermingled clusters of dSPNs and iSPNs coactivated before movement. Dopamine depletion unbalanced SPN activity rates and disrupted the movement-encoding iSPN clusters. Matching their clinical efficacy, L-DOPA or agonism of the D₂ dopamine receptor reversed these abnormalities more effectively than agonism of the D₁ dopamine receptor. The opposite pathophysiology arose in L-DOPA-induced dyskinesia, during which iSPNs showed hypoactivity and dSPNs showed unclustered hyperactivity. Therefore, both the spatiotemporal profiles and rates of SPN activity appear crucial to striatal function, and next-generation treatments for basal ganglia disorders should target both facets of striatal activity.

Comorbidity Analysis between Alzheimer's Disease and Type 2 Diabetes Mellitus (T2DM) Based on Shared Pathways and the Role of T2DM Drugs

Background:

Various studies suggest a comorbid association between Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM) indicating that there could be shared underlying pathophysiological mechanisms.

Objective:

This study aims to systematically model relevant knowledge at the molecular level to find a mechanistic rationale explaining the existing comorbid association between AD and T2DM.

Method:

We have used a knowledge-based modeling approach to build two network models for AD and T2DM using Biological Expression Language (BEL), which is capable of capturing and representing causal and correlative relationships at both molecular and clinical levels from various knowledge resources.

Results:

Using comparative analysis, we have identified several putative “shared pathways”. We demonstrate, at a mechanistic level, how the insulin signaling pathway is related to other significant AD pathways such as the neurotrophin signaling pathway, PI3K/AKT signaling, MTOR signaling, and MAPK signaling and how these pathways do cross-talk with each other both in AD and T2DM. In addition, we present a mechanistic hypothesis that explains both favorable and adverse effects of the anti-diabetic drug metformin in AD.

Conclusion:

The two computable models introduced here provide a powerful framework to identify plausible mechanistic links shared between AD and T2DM and thereby identify targeted pathways for new therapeutics. Our approach can also be used to provide mechanistic answers to the question of why some T2DM treatments seem to increase the risk of AD.

Call to Caution with the Use of Atypical Antipsychotics for Treatment of Depression in Older Adults

Atypical antipsychotics are increasingly being used to manage depression in older adults where these symptoms can often be refractory to first-line treatment with selective serotonin reuptake inhibitors (SSRIs) or serotonin norepinephrine reuptake inhibitors (SNRIs). Unfortunately, atypical antipsychotics can be associated with the development of extrapyramidal symptoms (EPS), with drug-induced parkinsonism (DIP) being the most common movement disorder induced by this class of medication. The management of treatment-resistant depression in older adults is of particular concern as depression is a common feature of idiopathic Parkinson’s disease (IPD) and can manifest prior to the development of motor symptoms. Herein, we discuss the use of atypical antipsychotics for the management of depression in older adults including the risk of DIP and propose that antipsychotics may potentially unmask IPD.

Drug-induced parkinsonism following chronic methamphetamine use by a patient on haloperidol decanoate

This report attempts to highlight that use of an antipsychotic and concurrent chronic use of methamphetamine can cause drug-induced parkinsonism. Methamphetamine is usually not encountered in the list of agents that induce drug-induced parkinsonism and so its consideration particularly during chronic use by a patient who is also on an antipsychotic is worthwhile because of its popularity as an illegal narcotic. This case report describes just such a case of drug-induced parkinsonism which is a subacute syndrome that mimics Parkinson's disease. Although less alarming than dystonia, it is more common, more difficult to treat and can be the cause of significant disability during maintenance treatment especially in the elderly. In most cases, symptoms are reversible in days or weeks, but occasionally, especially in the elderly, or if long-acting injectable antipsychotics are used-as in this case-symptoms may last for weeks or months. The report also illustrates the neuronal workings due to chronic methamphetamine-use and the additive effects of dopamine blockade by antipsychotics such as haloperidol.

Parkinson's disease between internal medicine and neurology

General medical problems and complications have a major impact on the quality of life in all stages of Parkinson's disease. To introduce an effective treatment, a comprehensive analysis of the various clinical symptoms must be undertaken. One must distinguish between (1) diseases which arise independently of Parkinson's disease, and (2) diseases which are a direct or indirect consequence of Parkinson's disease. Medical comorbidity may induce additional limitations to physical strength and coping strategies, and may thus restrict the efficacy of the physical therapy which is essential for treating hypokinetic-rigid symptoms. In selecting the appropriate medication for the treatment of any additional medical symptoms, which may arise, its limitations, contraindications and interactions with dopaminergic substances have to be taken into consideration. General medical symptoms and organ manifestations may also arise as a direct consequence of the autonomic dysfunction associated with Parkinson's disease. As the disease progresses, additional non-parkinsonian symptoms can be of concern. Furthermore, the side effects of Parkinson medications may necessitate the involvement of other medical specialists. In this review, we will discuss the various general medical aspects of Parkinson's disease.

Herbal medicine treatment for drug-induced parkinsonism

OBJECTIVES

To evaluate the role of herbal medicine in drug-induced parkinsonism (DIP) and identify an optimal treatment approach.

DESIGN

Retrospective review of DIP cases treated with herbal medicine.

SETTINGS/LOCATION

The Parkinson's clinic at Kyung Hee Traditional Korean Medicine Hospital, Korea.

PATIENTS

Twenty-one patients whose clinical outcome and offending drug could be identified.

OUTCOME MEASURES

Clinical features, treatments, and outcomes and summarized the clinical course and treatment in each case.

RESULTS

Twelve patients had levosulpiride-induced parkinsonism and 9 had parkinsonism induced by another drug. The offending drugs were discontinued in all patients, and all patients received herbal medications during treatment. Nine of 12 patients with parkinsonism from levosulpiride and 4 of 9 patients with parkinsonism from other drugs had complete reversal of symptoms. The most frequently used herbal formula was Ukgansan (Yigansan). DIP in the levosulpiride group tended to improve faster with herbal medicine, and the percentage of improvement was higher.

CONCLUSIONS

Optimal herbal medicine treatments chosen after a careful history and evaluation for risk factors may be helpful in reversing DIP.

Dothiepin-induced transient hypomania and extrapyramidal syndrome

A case has been reported here, who developed transient hypomanic symptoms as well as extrapyramidal symptoms after being switched from sertraline to dothiepin therapy. The possible mechanisms and clinical implications of the same are discussed.

Drug-induced parkinsonism

INTRODUCTION

Drug-induced parkinsonism (DIP) is the second most common cause of parkinsonism after idiopathic Parkinson's disease (iPD). Initially reported as a complication of antipsychotics, it was later recognized as a common complication of antidepressants, calcium channel antagonists, gastrointestinal prokinetics, antiepileptic drugs and many other compounds. Despite being a major health problem in certain populations, it seems to be frequently overlooked by the medical community.

AREAS COVERED

This paper approaches the concept of DIP, reviews its epidemiology, clinical features and ancillary tests recommended for a correct diagnosis. The authors discuss the different drugs and its pathogenic mechanisms. The relevance of an early recognition and recommendations for a correct management are commented.

EXPERT OPINION

Prescribers need to remain vigilant for DIP, particularly in the elderly, patients taking multiple drugs and those with genetic risk factors involved in iPD. Cessation of the causing agent is the main treatment and there is no evidence of benefit for the use of anticholinergics or levodopa. If the medication cannot be withdrawn, it should be switched to agents with a lower risk of DIP.

Drug-induced parkinsonism

Drug-induced parkinsonism (DIP) is the second-most-common etiology of parkinsonism in the elderly after Parkinson's disease (PD). Many patients with DIP may be misdiagnosed with PD because the clinical features of these two conditions are indistinguishable. Moreover, neurological deficits in patients with DIP may be severe enough to affect daily activities and may persist for long periods of time after the cessation of drug taking. In addition to typical antipsychotics, DIP may be caused by gastrointestinal prokinetics, calcium channel blockers, atypical antipsychotics, and antiepileptic drugs. The clinical manifestations of DIP are classically described as bilateral and symmetric parkinsonism without tremor at rest. However, about half of DIP patients show asymmetrical parkinsonism and tremor at rest, making it difficult to differentiate DIP from PD. The pathophysiology of DIP is related to drug-induced changes in the basal ganglia motor circuit secondary to dopaminergic receptor blockade. Since these effects are limited to postsynaptic dopaminergic receptors, it is expected that presynaptic dopaminergic neurons in the striatum will be intact. Dopamine transporter (DAT) imaging is useful for diagnosing presynaptic parkinsonism. DAT uptake in the striatum is significantly decreased even in the early stage of PD, and this characteristic may help in differentiating PD from DIP. DIP may have a significant and longstanding effect on patients' daily lives, and so physicians should be cautious when prescribing dopaminergic receptor blockers and should monitor patients' neurological signs, especially for parkinsonism and other movement disorders.

Acute vomiting in cats: rational treatment selection

PRACTICAL RELEVANCE

The control of nausea and vomiting in cats is important in order to prevent the development of food aversion, anorexia (with its associated complications of weight loss and dehydration), and hepatic lipidosis.

CLINICAL CHALLENGES

There are several antiemetic drugs that are clinically effective in cats. Making a rational choice from the available options requires knowledge of the likely cause of the vomiting, and the mechanisms of action and side effects of each drug. For example, a drug such as prochlorperazine, which can cause sedation, may be a useful first-line choice in a hospitalized cat that requires mild sedation to be handled, but would be undesirable in a critically ill cat.

AUDIENCE

For companion animal and feline practitioners, the vomiting cat is a common presentation.

EVIDENCE BASE

The guidance provided in this review draws on the findings of clinical trials in humans, experimental studies in cats, some clinical trials in cats, and clinical experience.

Spontaneous movement disorders in antipsychotic-naive patients with first-episode psychoses: a systematic review

BACKGROUND

Spontaneous movement disorders (SMDs), such as spontaneous dyskinesia and parkinsonism, have been described in patients with schizophrenia who have never been treated with antipsychotic medication. Their presence has been documented extensively in chronic schizophrenia but not at the time of illness onset.

METHOD

We performed a systematic review of studies investigating spontaneous abnormal movements elicited on clinical examination in antipsychotic-naive patients with first-episode psychosis.

RESULTS

We identified a total of 13 studies. Findings suggest a spontaneous dyskinesia median rate of 9% and a spontaneous parkinsonism median rate of 17%. Information on akathisia and dystonia was limited. The presence of SMDs may be associated with negative symptoms and cognitive dysfunction.

CONCLUSIONS

These findings support the notion that spontaneous abnormal movements are part of a neurodysfunction intrinsic to the pathogenesis of schizophrenia. Future studies should further investigate the role of basal ganglia and extrapyramidal pathways in the pathophysiology of psychosis, with particular attention to treatment implications.

Adenosine antagonists reverse the cataleptic effects of haloperidol: implications for the treatment of Parkinson's disease

The effects of adenosine antagonists were compared in two rodent models of Parkinsonian symptoms. In the first experiment the dopamine D2 antagonist, haloperidol, was used to induce catalepsy. It was found that treatment with the non-selective adenosine antagonist caffeine significantly reduced catalepsy at each dose. Treatment with the selective A1 antagonist CPT also produced a significant reduction in catalepsy, as did treatment with the selective A2A antagonist SCH58261. In the second experiment haloperidol was used to suppress locomotor activity in an open field test. Treatment with caffeine significantly increased locomotion reduced by haloperidol, but not at all doses tested. Treatment with CPT also increased haloperidol-suppressed locomotor activity in dose-dependent manner. Surprisingly, treatment with SCH58261 did not significantly increase locomotor activity in animals treated with haloperidol at any dose tested. While some of these results were unexpected, the overall pattern suggests that adenosine antagonists would be useful as therapies for Parkinsonian patients as they appear to increase movement. The results also suggest that in acute timelines A1 antagonists may be more beneficial than previously supposed.

Comparative features of the epidemiology of multiple sclerosis and Parkinson's disease: Environmental factors of potential etiological importance

Multiple sclerosis (MS) and Parkinson's disease (PD) are diseases of unknown cause. The etiology of MS is usually considered to be due to a number of potential biological agents while the etiology of PD is usually associated with toxic agents. Despite these differences, both pathologies have strong epidemiological similarities. A comparative analysis is performed of the epidemiology of MS and PD. Potential causal factors for PD may include dopamine-like pharmacological agents. It is proposed that potential causal agents such as certain drugs plus certain vaccines could explain rationally the epidemiology of MS. Ecology and genetics could not be the appropriate lines of research in the etiology of MS/PD because they are supported only in part by the epidemiology.

Drug-induced parkinsonism

Drug-induced parkinsonism (DIP) is the second cause of akinetic rigid syndrome in the Western world and its prevalence is increasing and approaching that of idiopathic Parkinson's disease due to the ageing of the population and to the rising of polypharmacotherapy. DIP was initially reported as a complication of neuroleptics in psychiatric patients, but it has also been described with a great diversity of compounds such as antiemetics, drugs used for the treatment of vertigo, antidepressants, calcium channel antagonists, antiarrythmics, antiepileptics, cholinomimetics and other drugs. Although traditionally considered reversible, DIP may persist after drug withdrawal. At least 10% of patients with DIP develop persistent and progressive parkinsonism in spite of the discontinuation of the causative drug. Irreversible or progressive DIP has been considered as an indication of presymptomatic parkinsonian deficit, unmasked but not caused by the offending drug, but it could be explained by persistent toxicity of the responsible pharmacological agents on the nigrostriatal dopamine pathway. The best treatment of DIP is prevention, including the avoidance of prescription of causative drugs whenever it is not strictly necessary. In patients who require potentially risky medication, it is necessary to perform adequate monitoring for early parkinsonian deficits and early discontinuation if these deficits appear. Atypical neuroleptics are associated with lower risk than first generation antipsychotic drugs. Special precautions are needed in elderly subjects, in patients treated with multiple drugs for prolonged periods of time and in those with familial risk factors including familial parkinsonism or tremor, or in those with genetic variants of genes involved in idiopathic Parkinson's disease.

Differential action of anti-emetic drugs on defecation and emesis induced by prostaglandin E2 in the ferret

In the present studies we investigated the mechanism of action of prostaglandin E2 (1 mg/kg, i.p.) to induce emesis and defecation and/or tenesmus in the ferret. The emesis was antagonized significantly (P<0.05) by ondansetron (0.3 and 1 mg/kg, i.p.) and (+)-(2S,3S)-3-(2-methoxybenzylamino)-2-phenlypiperidine hydrochloride (CP-99,994; 10 mg/kg, i.p.), but neither compound reduced defecations and/or tenesmus, with ondansetron (0.3 mg/kg) actually producing a slight increase (P<0.05). Droperidol (1 and 3 mg/kg), metoclopramide (0.3 and 3 mg/kg), domperidone (0.3 and 3 mg/kg), promethazine (0.3 and 3 mg/kg) and scopolamine (0.3 and 3 mg/kg) failed to reduce prostaglandin E2 induced emesis. However, droperidol (1 and 3 mg/kg) and scopolamine (0.3 and 3 mg/kg) reduced significantly the defecatory and/or tenesmus response (P<0.05). Bilateral abdominal vagotomy was ineffective to reduce emesis and defecations and/or tenesmus. The data suggests that 5-HT3 receptor and NK1 tachykinin receptor antagonists could be useful in the clinic to prevent emesis but not defecations induced by prostaglandin E2.

Synthesis, SAR studies, and evaluation of 1,4-benzoxazepine derivatives as selective 5-HT1A receptor agonists with neuroprotective effect: Discovery of Piclozotan

A new series of 1,4-benzoxazepine derivatives was designed, synthesized, and evaluated for binding to 5-HT1A receptor and cerebral anti-ischemic effect. A lot of compounds exhibited nanomolar affinity for 5-HT1A receptor with good selectivity over both dopamine D2 and alpha1-adrenergic receptors. Among these compounds, 3-chloro-4-[4-[4-(2-pyridinyl)-1,2,3,6-tetrahydropyridin-1-yl]butyl]-1, 4-benzoxazepin-5(4H)-one (50: SUN N4057 (Piclozotan) as 2HCl salt) showed remarkable neuroprotective activity in a transient middle cerebral artery occlusion (t-MCAO) model.

Médicaments, maladie de Parkinson et syndromes parkinsoniens : actualités de pharmacovigilance

This paper reviews recent data on the pharmacovigilance of antiparkinsonian drugs and drugs inducing parkinsonian syndroms. Sudden sleep attacks were first described in 1999 with dopamine agonists. In fact, they can be induced by all the dopaminergic antiparkinsonian drugs. Favorising factors are duration of the disease, dose of dopaminergic drugs, daytime somnolence or dysautonomia. This adverse drug reaction can be serious leading, for example, to road accidents. Cardiac valvulopathies were more recently (end of 2002) described with pergolide. Thus, this dopamine agonist should now be prescribed as a last choice among dopamine agonists. Dopamine drugs (levodopa as well as dopamine agonists) can induce hypersexual behaviours or pathological gambling. Among the long list of drugs inducing parkinsonian syndroms, recent data suggest the involvement of serotoninergic antidepressants, valproic acid and trimetazidine. Finally, these data on pharmacovigilance allow to precise the physiological role of dopamine: beside its motor and psychic effects, dopamine is also involved in the sleep-arousal control. It is also an important mediator for pleasure, hedonic regulations and sexual behaviour. This review also underlines the major role of spontaneous reports to the pharmacovigilance systems to identify new adverse drug reactions.

New piperidinyl- and 1,2,3,6-tetrahydropyridinyl-pyrimidine derivatives as selective 5-HT1A receptor agonists with highly potent anti-ischemic effects

A series of new piperidinyl- and 1,2,3,6-tetrahydropyridinyl-pyrimidine derivatives were synthesized. Among these compounds, 4-methyl-2-(1,2,3,6-tetrahydropyridin-4-yl)pyrimidine derivative 23 (SUN N5147) exhibited sub-nanomolar affinity for 5-HT1A receptor with 1000-fold selectivity over both dopamine D2 and alpha1-adrenergic receptors and remarkable neuroprotective activity in a transient middle cerebral artery occlusion (t-MCAO) model.

[Utility of dopamine transporter imaging (123-I Ioflupane SPECT) in the assessment of movement disorders]

OBJECTIVE

The aim of our work was to assess the diagnostic impact of 123-I Ioflupane SPECT in patients with tremor and some other sign of Parkinsonisms in regards to its categorization in Parkinsonisms with involvement/indemnity of presynaptic dopaminergic neurons as well as to establish a differential diagnosis between essential tremor (ET) and degenerative Parkinsonism.

METHODS

105 patients were included, 45 for differential diagnosis between Parkinsonism and ET, 52 to determine the origin of their Parkinsonism (degenerative vs secondary) and 8 with an established diagnosis, 5 Parkinson's disease and 3 ET. A dose of 185 MBq of Ioflupane 1-123 was administered and tomographic study acquired at 5 hours. After reconstruction, transaxial views were assessed by three observers. In all the patients, the diagnosis was established by a neurologist specialized in movement disorders, according to the symptoms, course, response to treatment and result of Ioflupane I-123.

RESULTS

42 patients were diagnosed of degenerative Parkinsonism (PD or Parkinsonism plus) and 63 of ET or secondary Parkinsonism. We obtained a values of sensitivity, specificity, PPV, NPV and accuracy of 93 %, 100 %, 100 %, 97 % and 97 % respectively. 123-I Ioflupane SPECT changed the treatment in 18 % of our patients.

CONCLUSIONS

123-I Ioflupane SPECT is a test of great value to establish the differential diagnosis between Parkinsonism vs ET and secondary vs degenerative Parkinsonism.

[Drug-induced parkinson syndromes]

Parkinsonism is defined by the association of akinesia with one of the following symptoms: extrapyramidal rigidity, tremor at rest, or postural instability. A drug-induced aetiology must always be suspected when parkinsonian symptoms appear, or increase in a patient receiving drug treatment. Indeed drug-induced is the more frequent aetiology of secondary parkinsonism. The main treatments involved are antipsychotic and other neuroleptic drugs (accounting for up to two-thirds of drug-induced parkinsonism), and calcium-channel entry blockers. The risk associated with antipsychotics is often dose dependent and related to dopamine D2 striatal receptor occupancy induced by the antipsychotic drug. This risk is inferior for the second generation antipsychotics. The other treatments more rarely involved are antidepressants (tricyclic and selective serotonin reuptake inhibitors), lithium, valproic acid, and others. The main criterium for imputability is chronological, regression of symptoms being observed in 40-74% of cases, after a mean delay of 3 months from cessation of treatment. However, 15% of cases persist after drug withdrawal, leading to a diagnosis of underlying idiopathic Parkinson's disease.

Changes in the spontaneous and stimulus-evoked activity in the somatosensory cortex of rats on acute manganese administration

In this work, acute effects of inorganic manganese exposure on nervous electrical activity of rats were investigated. Young adult male Wistar rats were prepared for recording in anaesthesia and spontaneous cortical as well as stimulus-evoked cortical and peripheral nervous activity was recorded before and after i.p. administration of 25 and 50 mg/kg Mn2+. The alterations found resulted possibly from several known neuronal effects of manganese. The frequency shift of spontaneous cortical activity, and increased latency and decreased amplitude of the peripheral nerve action potential, were probably due to the Mn(2+)-induced impairment of the mitochondria, whereas the increased amplitude of the evoked cortical response, to the effect on glutamatergic transmission.

Cortical motor activation in akinetic schizophrenic patients: A pilot functional MRI study

Akinesia is associated with supplementary motor area (SMA) dysfunction in Parkinson's disease. We looked for a similar association in patients with schizophrenia. Using functional magnetic resonance imaging (fMRI), we compared motor activation in 6 akinetic neuroleptic-treated schizophrenic patients and 6 normal subjects. Schizophrenic patients had a defective activation in the SMA, left primary sensorimotor cortex, bilateral lateral premotor and inferior parietal cortices, whereas the right primary sensorimotor cortex and a mesial frontal area were hyperactive. SMA was hypoactive in akinetic schizophrenic patients, emphasizing the role of this area in motor slowness. Other abnormal signals likely reflect schizophrenia-related abnormal intracortical connections.

Role of dopamine transporter imaging in routine clinical practice

Functional imaging of the dopamine transporter (DAT) defines integrity of the dopaminergic system and has its main clinical application in patients with mild, incomplete, or uncertain parkinsonism. Imaging with specific single positron emission computerised tomography ligands for DAT (FP-CIT, beta-CIT, IPT, TRODAT) provides a marker for presynaptic neuronal degeneration. Striatal uptake correlates with disease severity, in particular bradykinesia and rigidity, and monitoring of progression assists in clinical trials of potential neuroprotective drugs. DAT imaging is abnormal in idiopathic Parkinson's disease, multiple system atrophy and progressive supranuclear palsy and does not distinguish between these disorders. Dopamine loss is seen even in the earliest clinical presentations of true parkinsonism; a normal scan suggests an alternative diagnosis such as essential tremor, vascular parkinsonism (unless there is focal basal ganglia infarction), drug-induced parkinsonism, or psychogenic parkinsonism. Congruence between working clinical diagnosis and DAT imaging increases over time in favour of baseline DAT imaging results. Additional applications are characterising dementia with parkinsonian features (abnormal results in dementia with Lewy bodies, normal in Alzheimer's disease); and differentiating juvenile-onset Parkinson's disease (abnormal DAT) from dopa-responsive dystonia (normal DAT).

Potentiation of domperidone-induced catalepsy by a P-glycoprotein inhibitor, cyclosporin A

The distribution of domperidone (DOM), a peripheral dopamine D(2) receptor antagonist, to the brain is restricted by P-glycoprotein (P-gp) at the blood-brain barrier (BBB) and for this reason, DOM rarely causes parkinsonian symptoms, such as extrapyramidal side effects (EPS), unlike other dopamine D(2) antagonists. In this study, we aimed to investigate whether cyclosporin A (CsA), a P-gp inhibitor, potentiates EPS induced by DOM. The intensity of EPS was assessed in terms of the duration of catalepsy in mice. D(1), D(2) and mACh receptor occupancies at the striatum were measured in vivo and in vitro. Moreover, the distribution of DOM to the brain was investigated by using an in situ brain perfusion technique. The intensity of DOM-induced catalepsy was significantly potentiated by the coadministration of CsA. The in vivo occupancies of D(1), D(2) and mACh receptors, as well as the brain distribution of DOM, were increased by CsA. These results suggest that CsA increases the brain distribution of DOM by inhibiting P-gp at the BBB, and potentiates catalepsy by increasing the occupancies of the D(1) and D(2) receptors. The risk of DOM-induced parkinsonism may be enhanced by the coadministration of CsA.

Gender-related differences in the effects of nitric oxide donors on neuroleptic-induced catalepsy in mice

It has been suggested that nigrostriatal dopaminergic transmission is modulated by nitric oxide (NO). Since there is evidence that gonadal hormones can affect extrapyramidal motor behavior in mammals, we investigated the effects of isosorbide dinitrate (ISD), linsidomine (SIN-1) and S-nitroso-N-acetylpenicillamine (SNAP), three pharmacologically different NO donors, on neuroleptic-induced catalepsy in 60- to 80-day-old male and female albino mice. Catalepsy was induced with haloperidol (1 mg/kg, ip) and measured at 30-min intervals by means of a bar test. Drugs (or appropriate vehicle) were injected ip 30 min before haloperidol, with each animal being used only once. ISD (5, 20 and 50 mg/kg) caused a dose-dependent inhibition of catalepsy in male mice (maximal effect 120 min after haloperidol: 64% inhibition). In the females only at the highest dose of ISD was an attenuation of catalepsy observed, which was mild and short lasting. SIN-1 (10 and 50 mg/kg) did not significantly affect catalepsy in female mice, while a significant attenuation was observed in males at the dose of 50 mg/kg (maximal inhibition: 60%). SNAP (20 mg/kg) significantly attenuated catalepsy in males 120 min after haloperidol (44% inhibition), but had no significant effect on females. These results basically agree with literature data showing that NO facilitates central dopaminergic transmission, although the mechanisms are not fully understood. They also reveal the existence of gender-related differences in this nitrergic modulation in mice, with females being less affected than males.

Drug-induced parkinsonism

BACKGROUND

Drug-induced parkinsonism is common but often unrecognized. In addition to neuroleptics, many medications of diverse chemical nature may induce or exacerbate parkinsonism

REVIEW SUMMARY

Reports in the literature of drug-induced parkinsonism or of an underlying parkinsonian disorder exacerbated by a medication were located using MEDLINE, and pertinent bibliographies were reviewed. The range of medications that may induce or exacerbate parkinsonism spans the medical specialties. Along with neuroleptics, selective-serotonin reuptake inhibitors, lithium, valproic acid, calcium channel blockers, antiarrhythmics, procholinergics, chemotherapeutics, amphotericin B, estrogens, and others have been implicated.

CONCLUSIONS

This review seeks to enhance clinicians' knowledge of potential medications producing iatrogenic parkinsonism and encourage their vigilance in recognizing it.

Selective effects of insecticides on nigrostriatal dopaminergic nerve pathways

A degeneration of the nigrostriatal pathway is a primary component of Parkinson's disease (PD), and we have investigated the actions of insecticides on this pathway. For in vivo exposures, C57BL/6 mice were treated three times over a 2-week period with heptachlor, the pyrethroids deltamethrin and permethrin, or chlorpyrifos. One day after the last treatment, we observed that heptachlor and the pyrethroids increased maximal [3H]dopamine uptake in striatal synaptosomes from treated mice, with dose-dependent changes in Vmax displaying a bell-shaped curve. Western blot analysis confirmed increased levels of dopamine transporter (DAT) protein in the striatum of mice treated with heptachlor and permethrin. In contrast, we observed a small, but statistically significant decrease in dopamine uptake by 100 mg/kg chlorpyrifos. For heptachlor, doses that upregulated DAT expression had little or no effect on serotonin transport. Permethrin did cause an upregulation of serotonin transport, but required a 30-fold greater dose than that effective on dopamine uptake. Other evidence of specificity was found in transmitter release assays, where heptachlor and deltamethrin released dopamine from striatal terminals with greater potency than other transmitter types. These findings confirm that insecticides possess specificity for effects on striatal dopaminergic neurotransmission.

Synthesis and biological evaluation of new 4-arylpiperidines and 4-aryl-4-piperidinols: dual Na(+) and Ca(2+) channel blockers with reduced affinity for dopamine D(2) receptors

A series of novel 4-arylpiperidines and 4-aryl-4-piperidinols (2a-f, 3a-f and 4a-f) was synthesized and evaluated for blocking effects on both neuronal Na(+) and T-type Ca(2+) channels and binding affinity for dopamine D(2) receptors. Most of the compounds blockaded both ion channels with potency greater than or equal to flunarizine 1a which was adopted as a reference standard. In addition, these compounds had significantly reduced affinity for dopamine D(2) receptors which is common in this class of structure. Compounds 2a-f, 3a-f and 4a-f exhibited potent anticonvulsant effects following systemic (ip) administration on audiogenic seizures in DBA/2 mice, indicating their excellent brain permeability. The neuroprotective activity of 2a, 3a and 4a was also assessed in a transient middle cerebral artery occlusion (MCAO) model. These compounds significantly reduced neuronal damage without affecting ischemic hyperthemia, while flunarizine 1a produced only minor reductions. In particular, 4a had 1.7-fold the potency in this MCAO model but only 1/20 the affinity for dopamine D(2) receptors of 1a. The superposition of 2a, 3a and 4a on the basis of analyses of systematic conformation and similar structure has revealed that the cinnamyl, phenacyl and phenoxypropanol groups are likely to be structurally and biologically equivalent. Moreover, the superposition of 2a and 2f shows that diphenyl ether and biphenyl groups occupy a similar space, suggesting that both groups act as a bioisostere for the blockade of ion channels; however, this is not the case for dopamine D(2) receptors since only biphenyl compounds such as 2f had high affinity similar to flunarizine 1a. Compound 4a (SUN N5030) has a good pharmacological profile and may be useful in the alleviation and treatment of ischemic diseases.

Pharmacological involvement of the calcium channel blocker flunarizine in dopamine transmission at the striatum

Single intrastriatal microinjections of 25, 50 and 100nmol/microl of flunarizine in normal rats produced a dose-dependent turning behavior toward the injected side when they were challenged with apomorphine (1mg/kg, s.c). This effect was seen at 1, 3 and 7 days following administration of the high dose of flunarizine, but had subsided by 24h after administration of the intermediate dose; the low dose was ineffective. However, intrastriatal injection of the high dose of flunarizine resulted in a local lesion and thereafter this dose was not used. A similar dose-response relationship was determined for nifedipine, an L-type calcium channel antagonist. Injection of this antagonist did not result in apomorphine-elicited rotational behavior, reflecting its lack of antidopaminergic action. Intrastriatal injections of haloperidol (5microg/microl), an antagonist of dopamine D(2) receptors, or the sodium channel blocker lidocaine (40microg/microl), were given in order to compare their effects to those observed with flunarizine. Intracerebral injection of haloperidol produced ipsilateral turning in response to systemic administration of apomorphine given 60min after. The same response was obtained with the injection of apomorphine 10min after the injection of intracerebral lidocaine. This effect was no longer apparent 24h after the microinjection of haloperidol and 60min after the injection of lidocaine. In rats rendered hemiparkinsionian by lesioning the nigrostriatal pathway with 6OHDA, intrastriatal microinjection of flunarizine (50nmol/microl) significantly reduced apomorphine (0.2mg/kg, s.c.)-elicited turning behavior towards the non-lesioned side. These results suggest an antidopaminergic effect of flunarizine mediated by antagonistic action of post-synaptic striatal dopamine receptors. However, an action of the drug on sodium channels may not be ruled out. These studies offer additional supporting evidence for the induction or aggravation of extrapyramidal side-effects in patients receiving flunarizine.

Repetitive administration of tetrabenazine induces irreversible changes in locomotion and morphology of the substantia nigra in rats

We investigated the effects of a 7 day repetitive administration of tetrabenazine (TBZ), which depletes monoamines, on both locomotor behavior and histomorphometrial findings of substantia nigra in rats. These results were compared with the effects of a single dose of TBZ, which is a common paradigm in animal models of depression. A single dose of TBZ causes reversible decrease of voluntary movement and no histological changes. In contrast, as for repetitive administration, this experiment demonstrated irreversible and significant decrease in spontaneous locomotion, as well as histological changes in the neurons of the substantia nigra pars compacta. These results have led us to propose that prolonged TBZ administration could provide a novel and useful model for the behavioral characteristics and anatomical pathology of Parkinson's disease as one of the oxidative stress models induced by abnormal dopamine metabolism.

Other Parkinson syndromes

The etiology of parkinsonism is varied. Symptomatic parkinsonism is seen in the setting of genetic disorders, infectious processes, structural lesions, and as a result of concomitant medications. A thorough history and good examination will differentiate PD from the diverse group of conditions that can mimic it.