Neuroleptic-induced Parkinson's syndrome: clinical features and results of treatment with levodopa

Failure of recognition of drug-induced parkinsonism in the elderly

Our objective was to evaluate the ability of neurologists to recognize and diagnose drug-induced Parkinsonism (DIP) in the elderly. DIP is a diagnostic challenge because it can be indistinguishable from Parkinson's disease, especially in the elderly. It is frequently under-recognized by psychiatrists and primary care physicians. Atypical antipsychotics (AA) are advertised for their low propensity to cause DIP. This may add to problems with recognition. We performed a retrospective record review of consecutive new parkinsonian patients seen over 2 years in a movement disorders clinic to examine the frequency, causative agents, and diagnostic accuracy of DIP by physicians, particularly neurologists. Of 354 Parkinsonian patients evaluated, 24 (6.8%) had DIP, 46% of these were due to AA and 29% were caused by metoclopramide. Of the 24 patients with DIP, only one was previously diagnosed accurately according to records. Nineteen patients (79%) were previously evaluated by a neurologist, and none of them was diagnosed with DIP. The primary reason for failure to recognize DIP relates to under-recognition of AA as possible cause. A majority remained on the inciting agents while dopaminergic drugs were prescribed. DIP was reversible when the inciting drug was stopped. DIP is a common form of parkinsonism and is under-recognized, even by neurologists. AA and metoclopramide do not appear to be well-known to cause DIP. Cessation of the offending agent results in improvement of symptoms and would eliminate the need for dopaminergic agents, which are known to commonly cause side effects in the elderly.

Levodopa responsiveness in disorders with parkinsonism: a review of the literature

A literature review was conducted to investigate whether or not levodopa (LD) responsiveness (LR) is a useful criterion in the diagnosis of parkinsonian disorders. Although LR does appear to differ among the parkinsonian disorders, there is considerable confusion in the literature. While most patients with Parkinson's disease (PD) have a sustained benefit from LD, a small minority of patients with documented PD do not respond. The literature suggests that the LR rate is higher for multiple system atrophy (MSA), progressive supranuclear palsy (PSP), and corticobasal degeneration (CBD) than based on published diagnostic criteria. Magnitude and duration of response to LD and tolerability (time course, type and distribution of dyskinesias, mental effects and motor worsening) may be useful features in distinguishing PD, MSA, PSP, and CBD. Efforts should be directed toward better defining LR when used for diagnostic purposes and in scientific publications.

Odour identification test and its relation to cardiac 123I-metaiodobenzylguanidine in patients with drug induced parkinsonism

We investigated olfactory function and its relation to cardiac 123I-metaiodobenzylguanidine (MIBG) uptake in 15 patients with drug induced parkinsonism (DIP). The mean Cross Cultural Smell Identification (CCSI) score was significantly greater in patients with DIP than in those with Parkinson's disease (PD: 6.9 (1.6) vs 4.4 (2.2); p<0.001); however, the mean CCSI score in patients with DIP was not significantly different from controls. One patient with DIP, whose CCSI score was significantly reduced, also exhibited decreased cardiac MIBG uptake. DIP patients with CCSI scores within the normal range had normal cardiac MIBG uptake. Our study suggests that an olfactory function test may be a useful tool for detecting DIP unrelated to PD and for identifying patients with DIP who have subclinical PD.

Drug-induced parkinsonism in the elderly

Drug-induced parkinsonism is primarily caused by drugs that interfere with dopamine stimulation. Antipsychotic drugs are the most common offenders, but drug-induced parkinsonism may be seen with many other drugs, such as antiemetics and certain calcium-channel blockers. These medications are widely used in the elderly. Unlike the first generation of antipsychotic drugs, all of which cause parkinsonism and other extrapyramidal side effects, atypical antipsychotics have motor side effects that are not uniform. Among the atypicals, only quetiapine and clozapine are not associated with drug-induced parkinsonism. Since drug-induced parkinsonism is frequently under-recognized, it may be devastating in an elderly person with already compromised gait.

Clinical Implications of Cardiac-MIBG SPECT in the Differentiation of Parkinsonian Syndromes

Background and Purpose

¹²³I cardiac meta-iodobenzylguanidine (MIBG), an analogue of norepinephrine, has been used to estimate myocardial sympathetic nerve function. We investigate whether cardiac-MIBG SPECT is clinically applicable in the differentiation of Parkinson's disease (PD) from parkinsonian syndromes.

Methods

Cardiac-MIBG scintigraphy was performed in 27 controls, in 40 patients with PD and in 52 patients with other parkinsonian syndromes comprising 23 with multiple system atrophy (MSA), 26 with drug-induced parkinsonism (DIP), and 3 with corticobasal degeneration (CBD). The heart to mediastinum (H/M) uptake ratio was calculated for each subjects. Patients who either had medical conditions that confused the MIBG SPECT results or who took medications that interfere with MIBG accumulation were excluded from the study.

Results

Both early and delayed H/M ratios were in patients with PD significantly lower than in controls (early, 1.34±0.15 vs 1.79±0.19; delayed, 1.29±0.15 vs 2.06±0.29, p<0.001). In patients with PD, both early and delayed H/M ratios were significantly lower than those in patients with MSA (early, 1.68±0.23; delayed, 1.80±0.34, p<0.001), DIP (early, 1.83±0.24; delayed, 2.07±0.4, p<0.001), or CBD (early, 1.85±0.01; delayed, 1.99±0.19, p<0.001). Two patients with DIP, who were within the range of patients with PD, showed clinically similar courses of PD.

Conclusions

This study demonstrates that cardiac-MIBG is a clinically powerful tools to differentiate PD from other parkinsonian syndromes.

Impact of second-generation antipsychotics on the use of antiparkinson agents in nursing homes and assisted-living facilities

BACKGROUND

It is not known whether the reduced risk of motor adverse effects with second-generation antipsychotics (SGAPs) translates into less use of antiparkinson drugs (APDs).

OBJECTIVE

This study sought to estimate national rates of concomitant prescribing of APDs and antipsychotic drugs among elderly Medicare beneficiaries without Parkinson's disease (PD) who were residing in institutional settings from 1997 to 2000, a period during which the use of SGAPs increased greatly.

METHODS

This was a retrospective, cross-sectional, descriptive analysis using the Medicare Current Beneficiary Survey database. The population of interest was residents of nursing homes (NHs) and assisted-living facilities (ALFs) who received concomitant antipsychotic drugs and APDs but did not have PD. The primary objective of the study was to estimate the prevalence of concomitant APD and antipsychotic drug use for each study year, by use of first-generation antipsychotics (FGAPs) and SGAPs in each setting. A secondary objective was to compare concomitant use of APDs and individual antipsychotic agents (ie, clozapine, risperidone, olanzapine, quetiapine, ziprasidone, haloperidol, and thioridazine). We computed population-level annual prevalence rates for APD use and tested for statistically significant differences in APD use between FGAPs and SGAPs at the 5% significance level.

RESULTS

In NH residents, concomitant use of APDs and antipsychotics decreased from 20.7% in 1997 to 9.0% in 2000 (P < 0.005). APD use in NH residents declined similarly among users of FGAPs (from 23.2% in 1997 to 13.3% in 2000; P < 0.005) and SGAPs (from 18.4% in 1997 to 8.1% in 2000; P < 0.005). In ALF residents, concomitant use of APDs and antipsychotics decreased from 24.5% in 1997 to 21.1% in 2000 (P < 0.005). ADP use in ALF residents receiving FGAPs decreased from 26.9% in 1997 to 24.2% in 2000 (P < 0.005); there was no significant change in ADP use among ALF residents receiving SGAPs (from 21.0% in 1997 to 21.7% in 2000).

CONCLUSIONS

These results provide the first nationally representative estimate of the concomitant use of APDs and antipsychotic drugs among older individuals in long-term care settings. The decrease in concomitant use of APDs and antipsychotics when SGAPs were used in NHs suggests an association between the use of SGAPs and a reduction in the prescribing cascade, in which one drug is used to treat the adverse effects of another. The results also suggest that some Medicare beneficiaries in ALFs may be continued on APDs despite changes in the prescribing of antipsychotic agents, implying a need for better medication-management practices in these institutions.

Drug Insight: from disturbed motility to disordered movement—a review of the clinical benefits and medicolegal risks of metoclopramide

Metoclopramide, the only drug approved by the FDA for treatment of diabetic gastroparesis, but used off-label for a variety of other gastrointestinal indications, has many potentially troublesome adverse neurologic effects, particularly movement disorders. In this article, we comprehensively review the indications and side effects of metoclopramide, and describe some common pitfalls and strategies to minimize the medicolegal risks to the prescribing physician. Metoclopramide accounts for nearly a third of all drug-induced movement disorders, a common reason for a malpractice suit. The entire spectrum of drug-induced movement disorders, ranging from subtle to life-threatening, can ensue from its use; akathisia and dystonia are generally seen early in the course of metoclopramide-induced movement disorders, whereas tardive dyskinesia and parkinsonism seem to be more prevalent in chronic users. Female sex, age and diabetes are the major risk factors for metoclopramide-induced movement disorders. It is therefore incumbent on gastroenterologists and other prescribing physicians to become familiar with the adverse neurologic effects associated with the use of metoclopramide, and to take appropriate preventive and defensive measures.

Cardiac 123I-MIBG scintigraphy in patients with drug induced parkinsonism

Cardiac sympathetic dysfunction was investigated using 123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy in 20 patients with drug induced parkinsonism (DIP). The mean heart to mediastinum ratio was significantly greater in patients with DIP than in those with Parkinson's disease (mean (SD): 2.07 (0.39) v 1.28 (0.15), p<0.001). MIBG uptake was not different between the DIP patients and controls. Two DIP patients whose MIBG uptake was significantly reduced showed persistent parkinsonism and responded dramatically to levodopa.

The diagnosis of Parkinson's disease

The correct diagnosis of Parkinson's disease is important for prognostic and therapeutic reasons and is essential for clinical research. Investigations of the diagnostic accuracy for the disease and other forms of parkinsonism in community-based samples of patients taking antiparkinsonian medication confirmed a diagnosis of parkinsonism in only 74% of patients and clinically probable Parkinson's disease in 53% of patients. Clinicopathological studies based on brain bank material from the UK and Canada have shown that clinicians diagnose the disease incorrectly in about 25% of patients. In these studies, the most common reasons for misdiagnosis were presence of essential tremor, vascular parkinsonism, and atypical parkinsonian syndromes. Infrequent diagnostic errors included Alzheimer's disease, dementia with Lewy bodies, and drug-induced parkinsonism. Increasing knowledge of the heterogeneous clinical presentation of the various parkinsonisms has resulted in improved diagnostic accuracy of the various parkinsonian syndromes in specialised movement-disorder units. Also genetic testing and various other ancillary tests, such as olfactory testing, MRI, and dopamine-transporter single-photon-emission computed-tomography imaging, help with clinical diagnostic decisions.

[123I]-FP/CIT SPECT imaging for distinguishing drug-induced parkinsonism from Parkinson's disease

Parkinsonism in patients taking neuroleptic medications might be induced by dopamine receptor blockade alone or by dopamine blockade with nigrostriatal dysfunction. The differentiation between Parkinson's disease (PD) and drug-induced parkinsonism (DIP) is difficult to assess on clinical grounds alone. In this study, we have evaluated the clinical characteristics and striatal binding of (123)I-FP-CIT (N-omega-fluoropropyl-2beta-carboxymethoxy-3beta-{4-iodophenyl}tropane) in patients who developed DIP. A total of 20 patients (mean age, 62 +/- 13 years) who developed parkinsonism while on neuroleptic agents and 10 age-matched controls were enrolled. [123]-FP-CIT single-photon emission computed tomography (SPECT) was performed in all subjects. Neurological assessment was performed with the Motor part of the Unified Parkinson's Disease Rating Scale. [123]-FP-CIT binding of the entire striatum, caudate, and putamen was calculated. Patients were divided into two subgroups according to SPECT results for comparison of clinical characteristics. There were 9 patients who had normal scans and 11 who showed significantly diminished striatal binding, suggesting degeneration of the nigrostriatal system. Subanalyses of abnormal scans revealed significantly diminished binding in the caudate (P < 0.001 for right and left caudate) and putamen (P = 0.002 and P < 0.05 for right and left putamen, respectively). There were no differences in clinical features between patients with normal and abnormal scans. Symptoms included asymmetric tremor, bradykinesia, and rigidity in both groups. Freezing gait was present in two patients with normal scans. These results indicate that DIP is clinically indistinguishable from PD. Brain imaging with FP-CIT helps to determine whether DIP is entirely drug-induced or an exacerbation of subclinical PD.

Drug-induced movement disorders in children and adolescents

The use of psychotropic medication among children and adolescents is increasing with a concomitant increase in the incidence of drug-related movement disorders. This class of adverse reactions to medications can be divided into those that are acute in onset, others that are continuous as long as the offending drug is administered, and a final category consisting of symptoms that are persistent, even after the causative agent has been discontinued. Within these three categories, this review discusses the epidemiology, risk factors, clinical features and treatment of acute dystonic reactions, drug-induced parkinsonism, neuroleptic malignant syndrome, serotonin syndrome, acute akathisia, and the tardive syndromes. In addition, drugs that commonly cause tremor, chorea, or myoclonus are included.

DAT imaging in drug-induced and psychogenic parkinsonism

Parkinson's syndrome (PS) is frequently encountered in disorders associated with prominent degeneration of the nigrostriatal pathway as in Parkinson's disease, multisystem atrophy, and progressive supranuclear palsy (presynaptic PS). Drug-induced parkinsonism, a common, underdiagnosed health problem and psychogenic parkinsonism are causes of Parkinson's syndrome which, evidence suggests, occurs without degeneration of nigrostriatal structures. We review clinical features and results of DAT imaging in drug-induced parkinsonism and psychogenic parkinsonism. These two conditions normally give normal striatal DAT imaging results; an abnormal result in either case could exclude both conditions, corroborating a diagnosis of organic parkinsonism in uncertain cases.

Susceptibility to neuroleptic-induced parkinsonism--age and increased substantia nigra echogenicity as putative risk factors

OBJECTIVE

Patients treated by neuroleptics often develop neuroleptic-induced parkinsonism (NIP) to a varying extent. The reasons for this are discussed controversially in the literature. Previous transcranial sonography (TCS) findings of the substantia nigra (SN) in patients with idiopathic Parkinson's disease suggest a correlation of echogenicity with nigrostriatal dysfunction.

METHOD

One hundred psychiatric patients receiving neuroleptics were included. They underwent clinical examination for NIP (Simpson and Angus-scale) and, independently, TCS of the SN. History of smoking habits and medication were taken from the patient's chart.

RESULTS

We found a significant positive association of the prevalence of NIP with age (P < 0.01) and the echogenic area of the SN (P < 0.05). Neither type nor dosage of the neuroleptics was found to have any significant impact on the occurrence of NIP. Smokers displayed lower prevalence of NIP (P < 0.05) and lower EPS scores (P < 0.01).

CONCLUSIONS

These findings suggest that age and increased size of SN echogenicity are possible risk factors for NIP. In contrast, smoking seems to have a certain protecting effect.

Drug-induced movement disorders in children

The increased use of stimulants, antipsychotic agents, and antidepressant drugs in children by primary care physicians, psychiatrists, and neurologists has inevitably led to increased numbers of pediatric patients manifesting the side effects of these agents, many of which are movement disorders. Unlike the isolated abnormal involuntary movements associated with drugs prescribed for epilepsy or asthma, movement syndromes (eg, acute dystonic reaction, neuroleptic malignant syndrome, serotonin syndrome, tardive dyskinesia) associated with psychotropic drugs are complex, difficult to recognize, and potentially seriously disabling. Accurate clinical identification of these drug-induced syndromes is critical to engaging the proper therapeutic intervention for them.

Juvenile parkinsonism

Juvenile parkinsonism (JP) is a clinically and etiologically heterogeneous entity. Unlike in the adult form, secondary causes, hereditary and metabolic conditions, are the predominant causes of JP. Idiopathic Parkinson's disease is very rare in this age group. In most cases of JP, parkinsonism is accompanied by other neurologic features, such as dystonia, cognitive impairment, seizures, oculomotor and visual dysfunction, and ataxia. Systemic findings, such as liver dysfunction or hepatosplenomegaly, may be present depending on the cause. This review article describes the clinical characteristics, classification, genetic basis, pathophysiology, biochemistry, pathology, and treatment of JP.

Relationship between adverse effects of antipsychotic treatment and dopamine D(2) receptor polymorphisms in patients with schizophrenia

Extrapyramidal adverse symptoms (EPS) represent a major type of adverse events in treatment with typical antipsychotic drugs which share high affinity to the dopamine D(2) receptor (DRD2). Genetic variants of this receptor may modulate the therapeutic response and the severity of adverse symptoms of antipsychotics. We analyzed nine known polymorphisms of the DRD2 in 665 schizophrenic patients with European Caucasian ethnic background and compared the intensity of acute dystonia, extrapyramidal symptoms, akathisia, and tardive dyskinesia between carriers of different DRD2 genotypes. In a subgroup of 40 patients with most severe extrapyramidal symptoms we sequenced the coding region including the exon-intron junctions of the DRD2 gene. Functionally relevant DRD2 amino acid variants (Ser(310), Cys(311)) were rare or were not found at all (Ala(96)). Complete sequence analysis of sufferers from the most severe adverse effects revealed two new intronic polymorphisms and a silent polymorphism in exon 7, but no new amino acid variants beyond those which are already known. We found no significant association between these polymorphisms and the intensity of the different types of adverse neurologic effects of the antipsychotics. These results were obtained by correlating adverse events with each of the nine single nucleotide polymorphisms and by correlation with the estimated haplotypes. In conclusion, genetic variations in the DRD2 gene were no major predictors of the individually variable adverse effects from antipsychotic treatment in Caucasian schizophrenic patients.

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.

Antipsychotic-Induced movement disorders in the elderly: epidemiology and treatment recommendations

We reviewed the epidemiological aspects of antipsychotic-induced movement disorders as they pertain to older patients. The incidence and prevalence of drug-induced parkinsonism and tardive dyskinesia (TD) are significantly greater in the older patient than in the younger patient whereas akathisia seems to occur evenly across the age spectrum and dystonia is uncommon among older patients. The literature on risk factors associated with treatment-emergent movement disorders is highly variable. Treatment practices vary across the age range and the interaction between age and antipsychotic dosage confounds our understanding of the relative importance of treatment-related risk factors. However, there is general agreement that pre-existing extrapyramidal signs (EPS) increase the vulnerability of the patient to developing significant drug-induced movement disorders. Elderly patients with dementia are at greater risk than patients without dementia for persistent drug-induced EPS. Management of drug-induced movement disorders in the older patient requires careful consideration of the contraindications imposed by such agents as anticholinergics and beta-blockers. At present, well-controlled double-blind studies of second-generation antipsychotics such as clozapine, risperidone. olanzapine or quetiapine for reducing the risk of treatment-emergent movement disorders in the elderly have not been published. However, open-label studies of atypical antipsychotics demonstrate a markedly lower incidence of both EPS and TD compared with conventional antipsychotic treatment in the elderly. There is emerging literature in support of atypical antipsychotics for the treatment of existing drug-induced movement disorders. More controversial is the use of adjunctive antioxidants in newly treated patients who are vulnerable to drug-induced movement disorders. While the evidence is mixed in support of antioxidants for the treatment of TD, the possibility remains that prophylactic use of antioxidants may help reduce the incidence of TD. The development of a drug-induced movement disorder often reduces the quality of life in an elderly patient. Effective pharmacological management requires cooperation from the patient and family, which can be fostered early in the patient's care through proper informed consent. The risks and benefits of antipsychotic treatment in the elderly patient need to be communicated to the patient and family. At the present time, there is no consistently effective treatment for patients with TD once it develops. Therefore, attention should focus on its prevention and close monitoring.

Tardive and idiopathic oromandibular dystonia: a clinical comparison

OBJECTIVE

Most patients with tardive dystonia have a focal onset involving the cranial-cervical region. Because of its resemblance to idiopathic cranial dystonia, a common form of dystonia, it often poses a diagnostic problem. To compare clinical features and response to botulinum toxin (BTX) injections between patients with tardive and idiopathic oromandibular dystonia (OMD).

METHODS

Patients seen in a movement disorder clinic who satisfied the inclusion criteria for tardive or idiopathic OMD were studied. The clinical variables and responses to BTX between the two groups of patients were compared. In the tardive group, we also compared the clinical variables between those with oro-facial-lingual stereotypies, and those without.

RESULTS

Twenty four patients with tardive OMD and 92 with idiopathic OMD were studied. There were no differences in the demographic characteristics. Most were women, with duration of symptoms longer than 8 years. The mean duration of neuroleptic exposure was 7.1 (SD 7.9) years. Jaw closure was the most frequent subtype of OMD (tardive=41.7%, idiopathic=51.1%). Idiopathic patients were more likely to have coexistent cervical dystonia (p<0.05), whereas isolated OMD was significantly higher in tardive patients (p<0.05). Limb stereotypies, akathisia, and respiratory dyskinesia were seen only in the tardive OMD. Frequency of oro-facial-lingual stereotypy was significantly higher in the tardive than the idiopathic group (75.0% v 31.5%, p<0.0001). The peak effect of BTX was similar in both groups.

CONCLUSIONS

Oro-facial-lingual stereotypies were significantly more frequent in the tardive than the idiopathic group. Presence of stereotypic movements in the limbs, akathisia, and respiratory dyskinesias in patients with OMD strongly suggests prior neuroleptic exposure. Dystonia in tardive OMD is more likely to be restricted to the oromandibular region, whereas in patients with idiopathic OMD, there is often coexistent cervical dystonia. BTX is equally effective in both groups of patients.

Parkinson's disease and neuropsychological assessment

Neurological aspects of Parkinson's disease including symptomology, etiology, and chemotherapy are briefly reviewed. Recent developments in each area are also presented. Clinical considerations relevant to neuropsychological testing with the Parkinson's disease patient are discussed in terms of confounds that may hinder the accuracy of test result interpretation.

Extrapyramidal syndromes in neuroleptic-treated patients: prevalence, risk factors, and association with tardive dyskinesia

Prevalence and risk factors for extrapyramidal syndromes (EPS) were investigated in a sample of 1,559 patients. The overall prevalence of EPS was 29.4% (N = 458). Among the EPS-diagnosed patients, parkinsonism as assessed by the presence of core parkinsonian symptoms (rigidity, tremor, bradykinesia) was present in 65.9% of patients (N = 302), akathisia in 31.8% (N = 145), and acute dystonia in 2.1% (N = 10). Old age and long-term neuroleptic drug (NL) treatment were significantly associated with EPS in both the univariate and the multivariate analyses, whereas no relationship was observed with average NL daily doses and current NL treatment. EPS was diagnosed in 50.2% of 285 patients with persistent tardive dyskinesia (TD). Distribution of EPS in patients with TD showed that tremor and akathisia were more frequent in peripheral TD cases than in orofacial TD cases. Furthermore, there was a stronger association of NL-induced parkinsonism with peripheral TD than with orofacial TD. This study suggests that the association between EPS and TD may be limited to specific subtypes of TD. Peripheral TD showed a higher association with parkinsonism and with akathisia, suggesting that these symptoms may share a common pathophysiology.

Haloperidol induces persistent down-regulation of tyrosine hydroxylase immunoreactivity in substantia nigra but not ventral tegmental area in the rat

The dopamine antagonist haloperidol can cause tardive side-effects that may persist after the drug is withdrawn. We studied the time course of changes in dopaminergic neurons of the substantia nigra and ventral tegmental area following withdrawal of haloperidol. Rats received daily intraperitoneal injections of saline or haloperidol for eight weeks and were killed at two, four or 12 weeks after the final injection. Sections of substantia nigra and ventral tegmental area were processed for tyrosine hydroxylase immunohistochemistry. Quantitative morphometric analysis was carried out blinded in order to determine the number, cell body size and topography of tyrosine hydroxylase-positive cells, and the immunoreactive area of the substantia nigra and ventral tegmental area. In haloperidol-treated rats, tyrosine hydroxylase-positive cell counts were normal in ventral tegmental area but were decreased in substantia nigra by 34% at two weeks withdrawal and by 52% at four weeks withdrawal; cell counts were almost fully recovered by 12 weeks withdrawal. Cross-sectional area of tyrosine hydroxylase immunoreactivity within the substantia nigra demonstrated a similar pattern of reduction, with full recovery by 12 weeks withdrawal. Mean cell size, by contrast, was essentially unchanged at two and four weeks withdrawal, but was significantly decreased in sub-regions of substantia nigra at 12 weeks withdrawal. These results indicate that haloperidol can produce selective changes in midbrain dopamine neurons that persist long after discontinuation of the drug. This decrease in tyrosine hydroxylase-immunoreactive cell counts may play a role in the neurobiology of the persistent tardive syndromes associated with the use of neuroleptics.

Adverse neurobiological effects of long-term use of neuroleptics: human and animal studies

Neuroleptics have revolutionized the treatment of schizophrenia and other psychoses since the early 1950s. Several adverse neurobiological effects are, however, associated with the long-term use of these agents. This article will review human and animal studies of these adverse effects, and also present some new data. Tardive dyskinesia (TD) is the most widely studied potentially persistent movement disorder resulting from long-term neuroleptic treatment, and several risk factors for TD development have been identified. Although drug-induced parkinsonism (DIP) usually disappears after the offending agent is withdrawn, a small portion of patients may have persistent parkinsonism. It is however, unclear if this is an aging-related effect. Persistent cognitive impairment associated with long-term use of typical neuroleptics has not been well documented. Atypical antipsychotics may produce improvement in cognitive performance in patients with chronic schizophrenia. MRI changes that are secondary to neuroleptics are possible, but have not yet been studied adequately. There is one unconfirmed report of neurofibrillary tangles associated with long-term neuroleptic use. A number of investigators have reported vacuous chewing movements, and neuropathologic changes following prolonged administration of neuroleptics in animals. We discuss the implications of the various reported adverse effects of long-term use of neuroleptics.

Antiparkinsonian Agents : Clinically Significant Drug Interactions and Adverse Effects, and Their Management

The treatment of Parkinson's disease for most patients entails long term exposure to multiple agents, including anticholinergics, levodopa, amantadine, dopamine receptor agonists, catechol-O-methyltransferase inhibitors, selegiline (deprenyl) and clozapine. Patients with Parkinson's disease require medication for the control of the motor symptoms of their condition, for related medical or psychiatric symptoms of the disorder, and for concurrent medical problems, such as hypertension or cardiac disease.All these agents may cause adverse effects. There is a potential for drug-drug interactions between different antiparkinsonian agents and between antiparkinsonian medication and the other drugs a patient may be taking. Clinicians caring for patients with Parkinson's disease must be knowledgable about the potential adverse effects and drug interactions of an expanding array of medications for this condition.

Drug-induced movement disorders

Drug-induced movement disorders are often unrecognized, especially when not due to dopamine receptor blockers. This review discusses acute, subacute, and chronic syndromes. Pathophysiology relates almost always to dopaminergic transmission. Patient-dependent vulnerability and drug-dependent sensitivity are contributing factors. Young patients are more prone to acute reactions, and tardive or chronic conditions are more frequent in the elderly. Subclinical Parkinsonism can be unmasked by medication exposure. Treatment of tardive dyskinesia remains a challenging task for the clinician, but novel antipsychotics and dopamine depleting agents can be beneficial.

Drug-induced movement disorders

Parkinsonism, tremor, chorea-ballismus, dystonia, tardive dyskinesia, myoclonus, tics and akathisia can be induced by many drugs. The drugs that are most frequently implicated in movement disorders are antipsychotics, calcium antagonists, orthopramides and substituted benzamides (e.g. metoclopramide, sulpiride, clebopride, domperidone), CNS stimulants, antidepressants, anticonvulsants, antiparkinsonian drugs and lithium. It is possible for a single drug to induce 2 or more types of movement disorders in the same patient. Movement disorders are not always reversible after drug withdrawal.

A long-term follow-up study of cinnarizine- and flunarizine-induced parkinsonism

The natural course of calcium-entry blocker-induced parkinsonism was evaluated in 13 elderly patients previously exposed to cinnarizine or flunarizine or both for a median period of 7 months. Clinical assessments were carried out before drug discontinuation and twice thereafter over a period lasting < or = 7 years. None of the patients showed a full recovery of extrapyramidal signs, indicating that the long-term prognosis of the parkinsonism is less benign than previously reported. Two main patterns of clinical outcome were recognized (i.e., "remittent" and "persistent and not progressive" parkinsonism), whereas the development of a progressive disorder was observed only in one patient. No significant correlation was found between the patterns of outcome and some clinical variables, such as total duration of exposure to cinnarizine and flunarizine, cumulative drug dosages, and age at onset of parkinsonism. There was no significant difference in terms of family history of essential tremor or parkinsonism or both among patients with the two main patterns of clinical course.

Antipsychotic prescribing patterns and the treatment of extrapyramidal symptoms in older people

OBJECTIVES

We have previously identified antipsychotic use as a risk factor for the use of both dopaminergic and anticholinergic antiparkinsonian drugs in older people. This study examines whether and how such antipsychotic regimens were adjusted before the addition of an antiparkinsonian drug.

DESIGN

Retrospective comparison study

PARTICIPANTS

There were 1307 antipsychotic users begun on anticholinergic antiparkinsonian drugs and 345 antipsychotic users begun on dopaminergic drugs; 1864 antipsychotic users not prescribed antiparkinsonian drugs served as comparison subjects. Data were drawn from health care claims of patients aged 65-99 in the New Jersey Medicaid Program from 1981 to 1990.

MEASUREMENTS

We determined if antipsychotic regimens were discontinued, reduced in dosage, or modified to reduce extrapyramidal toxicity before the institution of antiparkinsonian therapy.

RESULTS

Thirty-five percent of the patients begun on dopaminergic drugs had their antipsychotic medication discontinued before beginning antiparkinsonian therapy; the antipsychotic was discontinued in only 12% of patients who started anticholinergic medications (P < .001). Among the smaller subset of patients with sufficient duration of antipsychotic exposure to examine changes in dose, 54% of patients begun on dopaminergic agents had their antipsychotic regimen reduced or discontinued before antiparkinsonian therapy, whereas 33% of patients begun on anticholinergic agents had one of these regimen changes (P < .001). Controlling for potential clinical and demographic confounders using multivariate logistic regression did not substantively alter these results.

CONCLUSIONS

These data indicate that physicians frequently fail to discontinue or modify an antipsychotic regimen before adding a new drug to treat probable drug-induced extrapyramidal symptoms. Such prescribing patterns preceding use of dopaminergic antiparkinsonian drugs suggest that addition of such drugs may represent an inappropriate attempt to treat presumed idiopathic Parkinson's disease in many cases.

Neuroleptic drug exposure and treatment of parkinsonism in the elderly: a case-control study

PURPOSE

Despite the widespread use of neuroleptic medications for the elderly, little is known about the frequency of treatment for drug-induced parkinsonian syndromes in this age group, particularly with L-dopa-type drugs, which are more appropriate for the treatment of true idiopathic Parkinson's disease.

PATIENTS AND METHODS

We identified 3,512 patients aged 65 to 99 enrolled in a large state Medicaid program who were newly prescribed a drug to treat parkinsonian symptoms. Controls were comparable program enrollees of similar age who had not been prescribed an antiparkinsonian drug. In a case-control study, we evaluated the use of neuroleptic drugs in the 90 days before initiation of antiparkinsonian therapy.

RESULTS

Patients taking neuroleptics were 5.4 times more likely to begin antiparkinsonian medication than were nonusers (95% confidence interval [CI] 4.8 to 6.1). They also had a greater than two-fold increase in risk of beginning therapy with a dopaminergic drug specific for idiopathic Parkinson's disease, not generally indicated for treatment of drug-induced parkinsonism (adjusted odds ratio 2.2, 95% CI 1.9 to 2.7). Clear dose-response relationships were demonstrated, as were differences among neuroleptics. Among all patients started on dopaminergic drugs in this population, 37% of such therapy was attributable to prior neuroleptic use. Continuation of the neuroleptic persisted in 71% of patients so treated.

CONCLUSION

Neuroleptic use is a common cause of extrapyramidal dysfunction in the elderly, and the side effect is frequently treated by adding an anticholinergic or dopaminergic drug to the regimen. The use of anticholinergic drugs presents risks of additional drug side effects; the use of dopaminergic drugs, generally not appropriate for drug-induced parkinsonian syndrome, suggests that extrapyramidal neuroleptic side effects may often be mistaken for idiopathic Parkinson's disease in older patients.

Persistent catalepsy associated with severe dyskinesias in rats treated with chronic injections of haloperidol decanoate

Patients who develop persistent parkinsonism while on chronic neuroleptic therapy may be predisposed towards the development of tardive dyskinesia (TD). We investigated this issue in an animal model of TD by examining the association between catalepsy and the syndrome of neuroleptic-induced vacuous chewing movements (VCMs). VCMs were measured every 3 weeks for 33 weeks while rats received injections of haloperidol decanoate. Catalepsy was measured after the second through the seventh injections of the depot neuroleptic. There were no correlations between the severity of catalepsy scores after the second or third injections of haloperidol and the severity of the overall VCM syndrome. However, the severity of the catalepsy score following the third through seventh injections of haloperidol strongly correlated with the concurrent number of VCMs. Persistent high catalepsy scores across the six catalepsy rating sessions were strongly associated with the development of persistent severe VCMs. These findings suggest that, to the extent that persistent parkinsonian signs in humans are associated with a propensity towards the development of TD, the VCM syndrome in rats is at least a partially faithful animal model of this relationship.

Drug-induced parkinsonism: a review

The main clinical features, pathophysiology and underlying mechanisms of drug-induced parkinsonism are reviewed. The clinical manifestations of drug-induced parkinsonism are often indistinguishable from idiopathic Parkinson's disease. However, some subtle differences may exist: for example drug-induced parkinsonism is often associated with tardive dyskinesias, bilateral symptoms and the absence of resting tremor, etc. Besides toxins (eg manganese, carbon monoxide or MPTP), many drugs are known to produce parkinsonism: dopamine blocking drugs (true neuroleptics used as antipsychotics: phenothiazines, butyrophenones, thioxanthenes but also sulpiride, "hidden" neuroleptics prescribed as anti-nausea or anti-vomiting drugs (such as metoclopramide and other benzamide derivatives), dopamine depleting drugs (reserpine, tetrabenazine), alpha-methyldopa, calcium channel blockers (flunarizine, cinnarizine, etc). The putative role of other drugs (eg fluoxetine, lithium, amiodarone) as well as the therapeutic management of this side effect are reviewed.

Tardive tremor

A variety of hyperkinetic movement disorders has been associated with the use of neuroleptics (dopamine receptor blocking drugs), but tardive tremor has not been previously documented. We describe five patients in whom tremor occurred after chronic treatment with neuroleptics, was aggravated by and persisted after neuroleptic withdrawal, and improved after treatment with the dopamine depleting drug tetrabenazine. This involuntary oscillatory movement, with a frequency range of 3-5 Hz, was most prominent during maintenance of a posture, but was also present at rest and during a goal-directed movement. The tremor was accompanied by other tardive movement disorders, including akathisia, chorea, dystonia, myoclonus, and stereotypy. There was no family history or other explanation for tremor in these patients. We suggest that this hitherto unreported movement disorder is best termed "tardive tremor."

Risk factors for neuroleptic-induced movement disorders

Chronic neuroleptic therapy may be associated with the development of diverse movement disorders including Tardive dyskinesia (TD), Parkinsonism, dystonia, and akathisia in a subset of schizophrenic patients. It is presently unknown why only a proportion of neuroleptic-treated patients develop these movement disorders. In the following communication, we present a series of studies which demonstrate that the development of these movement disorders may be facilitated by certain risk factors including disturbances in pineal melatonin functions, diabetes mellitus, cognitive deficits, suicidal behavior, and disturbances in the functions of the choroid plexus. Recognition of these biological factors may prove useful in: (a) further understanding of the pathophysiology of these disorders, and (b) identifying patients at risk for these movement disorders.

Neuroradiological covariates of drug-induced parkinsonism and tardive dyskinesia in schizophrenia

Computed tomographic (CT) studies have demonstrated structural brain abnormalities including cortical atrophy and enlarged lateral ventricles in a subset of schizophrenic patients including those with abnormal involuntary movements. In the following series of studies, we present our findings pertaining to neuroradiological covariates of drug-induced Parkinsonism and Tardive dyskinesia in schizophrenic patients. In these studies we have explored the relationship of Parkinsonism and Tardive dyskinesia to pineal and choroid plexus calcification. In addition, we also investigated the relationship of pineal calcification to schizophrenia, and specifically to the paranoid and nonparanoid subgroups. In a further series of studies, we investigated the neuroradiological covariates of disorders of gait and posture as well as tremor in schizophrenic patients with drug-induced Parkinsonism. In addition, we explored the relationship of Tardive dyskinesia and its subsyndromes to CT scan measurements of cortical and subcortical atrophy in schizophrenia. Our findings highlight the significance of the pineal gland in the pathophysiology of schizophrenia and drug-induced movement disorders. Furthermore, these studies underscore the heterogeneity of Parkinsonism and Tardive dyskinesia.

Clinical and instrumental assessment of neuroleptic-induced parkinsonism in patients with tardive dyskinesia

We evaluated 21 right-handed psychiatric patients with tardive dyskinesia (TD) for the presence and laterality of neuroleptic-induced tremor and rigidity. The goals of the study were to assess the frequency and coexistence of TD and neuroleptic-induced parkinsonism (NIP) using instrumental and clinical measurements and to evaluate the hypothesis that when TD and NIP coexisted in the same patient, they were more likely to appear in opposite limbs. Results indicated that a high percentage of TD patients had coexisting rigidity and tremor on the basis of both clinical ratings and instrumental procedures; however, only instrumental procedures were useful in identifying tremor and rigidity asymmetries. We found that TD and tremor or rigidity did not lateralize to opposite limbs, thus weakening the hypothesis that TD and NIP stemmed from reciprocal pathophysiological mechanisms.

Pyridoxine improves drug-induced parkinsonism and psychosis in a schizophrenic patient

Drug-induced Parkinsonism is a common serious side-effect of neuroleptic therapy. In cases of irreversible drug-induced Parkinsonism, pharmacological management is notoriously difficult. A schizophrenic patient with severe neuroleptic-induced Parkinsonism and Tardive Dyskinesia is presented in whom administration of pyridoxine (vitamin B6) (100 mg/d) resulted in dramatic and persistent attenuation of the movement disorders as well as reduction of psychotic behavior. Since pyridoxine deficiency is associated with marked reduction of cerebral serotonin concentrations and pineal melatonin production in rats, the effects of pyridoxine on the movement disorder and psychosis may have been mediated largely by enhancing serotonin and melatonin functions. An additional effect of excess pyridoxine administration on GABA and dopamine activity cannot be excluded. Pyridoxine has been reported to attenuate the severity of levodopa-induced dyskinesias in patients with Parkinson's disease and it is suggested that pyridoxine supplementation should be considered in psychiatric patients with drug-induced movement disorders including persistent Parkinsonism. An underlying pyridoxine deficiency in these patients may exacerbate the psychotic behavior and additionally, potentially increase the risk of drug-induced movement disorders.

Asymmetry of neuroleptic-induced rigidity: development of quantitative methods and clinical correlates

Twenty-six medicated schizophrenic patients and 14 normal controls underwent laboratory assessment for the presence and asymmetry of neuroleptic-induced rigidity to evaluate the sensitivity, reliability, and validity of a quantitative procedure. Measures of muscle stiffness were made in the upper extremities. Results indicated that 65% of the patients exhibited pathological rigidity. Moreover, 76% of these patients exhibited asymmetric rigidity, while the remaining 24% exhibited bilateral symptoms. Newly treated patients exhibited a greater laterality of rigidity toward the right side compared with patients who were on stable treatment regimens for at least 3 months. Since parkinsonism reflects dopamine receptor blockade by neuroleptic medication, probably in the striatum, we suggest that the lowered susceptibility of the right striatum to drug-induced parkinsonism supports the hypothesis that striatal dopaminergic activity may be asymmetric and more marked in the right striatum among recently treated patients.