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PubMed2000

Cholinergic medication for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Since the 1950's neuroleptic medication has been extensively used to treat people with chronic mental illnesses, such as schizophrenia. These may cause tardive dyskinesia (TD), abnormal, repetitive and involuntary movements, in up to 20% of those using the medication for longer than three months. One theory of causation supports the use of cholinergic drugs for the management of TD. OBJECTIVES: To determine whether the use of cholinergic agents (arecoline, choline, deanol, lecithin, meclofenoxate, physostigmine, RS 86) were associated with clinical improvement in neuroleptic-induced TD in people with schizophrenia or other chronic mental illnesses. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1995), Cochrane Schizophrenia Group's Register of trials (1995), EMBASE (1980-1995), LILACS (1982-1996), MEDLINE (1966-1995), PsycLIT (1974-1995), and SCISEARCH (1995) were undertaken. References of all identified studies were searched for further trial citations. Principal authors of trials were contacted. SELECTION CRITERIA: Reports identified in the search were included if they were controlled trials dealing with people with neuroleptic-induced TD and schizophrenia or other chronic mental illnesses who had been randomly allocated to either a cholinergic agent or to a placebo (or no intervention). DATA COLLECTION AND ANALYSIS: Seven different studies (8 references) were included in this review, and another ten trials are currently awaiting further data from authors. Data were independently extracted from these trials by each reviewer and odds ratios (OR) or average differences, with the 95% confidence intervals (95% CI) were estimated. The reviewers assumed that people who dropped out had no improvement. MAIN RESULTS: The studies failed to detect any significant advantage of deanol or lecithin when compared to placebo. Data from two deanol trials demonstrated an excess of side effects in the active treatment group. People on cholinergic compounds report a range of gastrointestinal adverse effects (anorexia, nausea, vomiting, diarrhea, abdominal pain), sedation, and undesirable body odour. One person died of acute aspiration in a deanol versus placebo cross-over study. REVIEWER'S CONCLUSIONS: This review provides no strong evidence for the use of cholinergic agents in the treatment of neuroleptic-induced tardive dyskinesia. While people receiving cholinergic treatment had a marginal benefit compared to placebo, because of the small sample size, the cumulative data must be interpreted as inconclusive. Clinicians and trialists considering using cholinergic agents to treat TD should balance the lack of evidence for the efficacy against the excess of side effects associated with these compounds.

Antipsychotic Agents↗
PubMedDate not supplied

Dyskinesia: L-dopa-induced and tardive dyskinesia.

Neuroleptic induced tardive dyskinesia and L-dopa-induced dyskinesia are the two most common types of drug-induced abnormal involuntary movements. These two drug-induced dyskinesias are clearly different with respect to the offending drugs and the underlying disease, but they both share a number of intriguing similarities in terms of clinical phenomenology, epidemiology, risk factors, pathophysiological mechanisms and therapeutic responses. In both instances, it is believed that some dysregulation occurring at the level of the striatal dopaminergic receptors, and related non-dopaminergic neurotransmitters systems are playing a crucial role in the development and persistence of the mechanisms causing dyskinesia. These long-lasting functional changes, known as the "priming" phenomenon, are responsible for an impaired balance within the relays of the cortico-subcortical motor loops that release an inadequate output from the basal ganglia leading to an abnormal motor behavior. From a therapeutic perspective, there are also many similarities in the strategies proposed to manage these two dyskinesias. In both cases, unprimed patients not previously exposed to the offending drugs, are offered alternative medications to reduce, at least partly, the risk of occurrence of future dyskinesia: "atypical" neuroleptics in the place of "typical" neuroleptics, and dopamine agonists in the place of L-dopa. In both cases, once dyskinesias are present, in already "primed" patients, both types of dyskinesia appear to be poorly and only partly reversible. Based on limited clinical evidence, it is a common proposal to switch the dyskinetic subject from "typical" to "atypical" neuroleptics for tardive dyskinesia, or to switch from (or more pragmatically to substitute as much as possible) L-dopa to a dopamine agonist for L-dopa-induced dyskinesia. In both cases, efficacious symptomatic antidyskinetic interventions, to reduce the severity of a ready present dyskinesia, are rare. There are some uncontrolled data suggesting that dopamine depleting agents, like tetrabenazine, are possibly useful for tardive dyskinesia; however, there is more clinical evidence to support the efficacy of amantadine and functional surgery in parkinsonian patients with L-dopa-induced dyskinesia.

Antiparkinson Agents↗
PubMed1981

[Electrophysiological and pharmacological analysis of L-dopa-induced dyskinesia and tardive dyskinesia (author's transl)].

Electrophysiological and pharmacological analysis of L-Dopa-induced dyskinesia and tardive dyskinesia (L.DD) due to neuroleptics was performed on 12 patients with Parkinson's disease and on 12 others with psychotic diseases. This analysis included the examination of spinal reflexes, monosynaptic H reflex, polysynaptic cutaneous reflex of the lower limb, muscular responses to passive movement [stretch reflex and shortening reaction (SR)] and the study of the motor response to a dopaminergic stimulus (I.V. injection of Piribedil (PBD), a dopamine agonist). There was no difference in EMG activity between L.DD and TD. Three EMG patterns can be distinguished: anarchic discharge pattern (ADA), tonic grouping discharge pattern (AST) and rhythmic burst pattern (ABR). PBD effects indicate a possible relationship between the EMG patterns and the sensitivity level of the motor dopamine receptors. During L-Dopa dyskinesia and tardive dyskinesia, the same changes in spinal reflexes were observed. Muscle tone tested by muscular responses to passive movement (shortening and myotatic reaction) was normal. Monosynaptic excitability explored by H/M ratio was within the normal range. In contrast, the polysynaptic nociceptive reflex was increased in every case. In Parkinsonian patients with L-Dopa dyskinesia, this pattern of the spinal reflexes was significantly different in comparison to the rigid phase. Intravenous infusion of PBD suppressed tremor and provoked the occurrence of dyskinetic activity in Parkinsonian patients with L-Dopa dyskinesia during the rigid phase. During the dyskinetic phase, as in tardive dyskinesia, PBD increases these phenomena and changes EMG activity in rhythmic pattern. It is suggested that L-Dopa dyskinesia and tardive dyskinesia can be determined by testing EMG activity, spinal reflexes and dopaminergic reactivity. There is evidence to suggest that the various types of involuntary abnormal movement represent a single entity, and that dopamine receptor supersensitivity may be involved.

Antipsychotic Agents↗
PubMed2000

Benzodiazepines for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a potentially disfiguring movement disorder of the orofacial region often caused by use of neuroleptic drugs. A wide range of strategies have been used to help manage TD and, for those who are unable to have their antipsychotic medication stopped or substantially changed, the benzodiazapine group of drugs has been suggested as a useful adjunctive treatment. OBJECTIVES: To determine the clinical efficacy of benzodiazepines for people with neuroleptic-induced tardive dyskinesia (TD) schizophrenia or other chronic mental illnesses. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1995), the Cochrane Schizophrenia Group's Register of trials (1995), EMBASE (1980-1995), LILACS (1982-1995), MEDLINE (1966-1995), PsycLIT (1974-1995), SCISEARCH (1995) and handsearching the references of all identified studies. SELECTION CRITERIA: The inclusion criteria for all randomised studies were that they should focus on people with schizophrenia or other chronic mental illnesses and neuroleptic-induced TD and compare the use of benzodiazepines to placebo or no intervention. DATA COLLECTION AND ANALYSIS: The reviewers extracted the data independently and the odds ratio (95% CI) or the average difference (95% CI) were estimated. The reviewers assumed that people who dropped out had no improvement. MAIN RESULTS: Two trials were able to be included in this review. The results of this review do not allow any confident interpretations on the clinical utility of benzodiazepines for the treatment of neuroleptic-induced TD. From the data combined in this review, benzodiazepines have no distinct advantages over placebo in the treatment of TD. Data on side effects were not reported in the included trials. REVIEWER'S CONCLUSIONS: No clear statement about the efficacy of benzodiazepines drugs, to treat neuroleptic-induced TD, could be provided.

Anti-Anxiety Agents↗
PubMed2000

Miscellaneous treatments for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a disabling movement disorder associated with the prolonged use of neuroleptic medication. This review, one in a series examining the treatment of tardive dyskinesia, will cover miscellaneous treatments not covered elsewhere. OBJECTIVES: The primary objective of this review was to determine whether the following interventions were associated with a reduction of TD in people with schizophrenia, or others chronic mental illnesses: botulin toxin, endorphin, estrogen, essential fatty acid, EX11582A, ganglioside, lithium, naloxone, periactin, phenylalanine, piracetam, stepholidine, tryptophan, neurosurgery, or ECT. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1995), Cochrane Schizophrenia Group's Register of trials (1995), EMBASE (1980-1995), LILACS (1982-1996), MEDLINE (1966-1995), PsycLIT (1974-1995), and SCISEARCH (1995) were undertaken. References of all identified studies were searched for further trial citations. Principal authors of trials were contacted. SELECTION CRITERIA: The inclusion criteria for all relevant randomised studies were that they should focus on people with schizophrenia or other chronic mental illnesses, with neuroleptic-induced TD and compare the use of the interventions listed above versus placebo or no intervention. DATA COLLECTION AND ANALYSIS: Forty references describing 31 different trials were identified by the search strategy. Of 31 trials, 15 trials were excluded, six trials were included, eight awaiting assessment and a further two trials are pending (awaiting translation, unable to locate). Data were independently extracted by each reviewer and the odds ratio or the average differences were estimated. The reviewers assumed that people who dropped out had no improvement. MAIN RESULTS: Data were available about the efficacy and safety of cerultide, essential fatty acids, estrogen, lithium and insulin. There was a significant improvement in TD associated with the use of insulin compared to placebo (OR = 0.04, 95%CI 0.01-0.24). No significant differences between the other compounds and placebo were identified. REVIEWER'S CONCLUSIONS: There is no strong evidence to support the use of any of the agents included in this review, however because of the small sample sizes, all results must be considered inconclusive. The association between low dose insulin and improvement of TD requires replication.

Antipsychotic Agents↗
PubMed1994

Dose-dependent differences in the development of reserpine-induced oral dyskinesia in rats: support for a model of tardive dyskinesia.

Rats treated with reserpine develop spontaneous orofacial dyskinesia that has features similar to tardive dyskinesia (TD) in humans. In contrast to TD, however, reserpine-induced oral dyskinesia develops rapidly reaching a maximal level within 3 days at a dose of 1 mg/kg per day. The present study examined whether rats administered lower doses of reserpine would develop the oral dyskinesia at a slower rate, similar to the protracted development of TD. Rats were administered 0, 0.01, 0.05, 0.1, or 1.0 mg/kg reserpine subcutaneously every other day for 100 days. Oral dyskinesia was measured by recording the incidence of tongue protrusions for 30 min on days 1, 4, 10, 20, 40, 60, and 100. The time course of the development of reserpine-induced oral dyskinesia varied dose-dependently. The response was evident within 4 days at 1 mg/kg, within 20 days at 0.1 mg/kg, within 60 days at 0.05 mg/kg, and was not evident at 0.01 mg/kg at any time during the 100 days of treatment. The protracted development of reserpine-induced oral dyskinesia at the lower doses is consistent with TD. Doses of reserpine that produced an increase in tongue protrusions also produced a 90-95% depletion of dopamine and an increase in the ratio of dopamine metabolites to dopamine in the caudate-putamen. The disruption of dopamine neurotransmission may be involved in development of the oral dyskinesia. Furthermore, it is suggested that the 1 mg/kg dose of reserpine may induce neurochemical changes similar to that produced by long-term neuroleptic treatment, but at an accelerated rate, thereby providing a new efficient model of TD.

Animals↗
PubMed2005

An assessment of emergent tardive dyskinesia and existing dyskinesia in patients receiving long-acting, injectable risperidone: results from a long-term study.

INTRODUCTION: Treatment-emergent tardive dyskinesia (TD) can be a serious side effect of antipsychotic treatment. Atypical antipsychotics are associated with a lower risk for TD than are conventional agents. A long-acting atypical antipsychotic, with more stable blood levels and lower peak blood levels than an oral formulation, may provide differential benefit regarding side effects, including movement disorders. This analysis assessed TD by defined research criteria in patients receiving long-acting, injectable risperidone. METHODS: Clinically stable subjects with schizophrenia or schizoaffective disorder participated in a 50-week, open-label trial of long-acting, injectable risperidone. TD was studied by defined research criteria (Schooler, N.R., Kane, J.M., 1982. Research diagnosis for tardive dyskinesia. Arch. Gen. Psychiatry. 39, 486-487; Americal Psychiatric Association, 2000. Diagnostic and Statistical Manual of Mental Disorders, fourth ed. American Psychiatric Association, Washington, DC). The severity of dyskinesia and other movement disorders were rated by the Extrapyramidal Symptom Rating Scale (ESRS). RESULTS: ESRS dyskinesia data were available for 662 patients. Five of 530 subjects without dyskinesia at baseline (0.94%) met the predefined criteria for emergent persistent TD during therapy. Based on either exposure to study medication or Kaplan-Meier analysis, the 1-year rate was 1.19%. Among the 132 subjects with dyskinesia at baseline, the mean score on the ESRS physician's exam for dyskinesia improved significantly at endpoint (-2.77; P<0.0001), regardless of anticholinergic drug use. (P=0.243 for patients with versus without anticholinergic drug use.) CONCLUSIONS: In this open-label study, treatment with long-acting risperidone was associated with a low rate of emergent persistent TD. Significant improvement in existing dyskinesias was noted. The TD rate reported here is consistent with other reports of atypical antipsychotics and substantially lower than with conventional antipsychotics.

Adult↗
PubMed1992

Prevalence of tardive dyskinesia, tardive dystonia, and respiratory dyskinesia among Chinese psychiatric patients in Hong Kong.

OBJECTIVE: Only scanty information on the prevalence of tardive dyskinesia in Chinese patients has been available. This study was undertaken to examine the prevalence of tardive dyskinesia, tardive dystonia, and respiratory dyskinesia in Chinese psychiatric patients in Hong Kong. METHOD: All inpatients of a mental hospital in Hong Kong, except those in the admission and children's wards, were surveyed with the Abnormal Involuntary Movement Scale, and standard research criteria were used to establish the diagnosis of tardive dyskinesia. In addition, patients were screened for tardive dystonia, according to published criteria, and for respiratory dyskinesia by physical examination and laboratory tests. RESULTS: Among the 917 patients surveyed, the prevalence rates were 9.3% for tardive dyskinesia, 0.4% for tardive dystonia, and 1.2% for respiratory dyskinesia. With multivariate analysis, greater age and a lower current dose of antipsychotic, but not the presence of mood disorder, were factors found to be significantly associated with tardive dyskinesia. CONCLUSIONS: The prevalence rates were much lower than those found in Western studies. This may indicate that there is an ethnic difference in the prevalence of these conditions. Prospective cross-cultural studies are necessary to explore this possibility.

Adolescent↗
PubMed2000

Neurotoxicity associated with neuroleptic-induced oral dyskinesias in rats. Implications for tardive dyskinesia?

Tardive dyskinesia is a serious motor side effect of long-term treatment with neuroleptics, with an unknown pathophysiologic basis. Brain damage and aging are prominent risk-factors, and together with the persistent character of the disorder, it is likely that long-lasting neuronal changes are involved in the pathogenesis. It has been hypothesized that striatal neurodegeneration caused by excitotoxic mechanisms and oxidative stress may play an important role in the development of the disorder, and the scope of the present work is to review the evidence supporting this hypothesis. The rat model of tardive dyskinesia has been used extensively in the field, and the usefulness of this model will be discussed. Neuroleptics are able to induce oxidative stress in vitro and increase striatal glutamatergic activity in rats, which may lead to toxic effects in the striatum. Drugs that block excitotoxicity inhibit the development of persistent oral dyskinesia in the rat model, and impaired energy metabolism leads to increased frequency of oral dyskinesia. There are also signs of altered striatal histology in rats with high frequency of oral dyskinesia. Furthermore, markers of increased oxidative stress and glutamatergic neurotransmission have been found in the cerebrospinal fluid of patients with tardive dyskinesia. In conclusion, several lines of evidence implicate neurotoxic events in the development of neuroleptic induced tardive dyskinesia.

Animals↗
PubMed1989

[Oral dyskinesia in rats after a single administration of haloperidol combined with GABA-linoleamide. A model of dyskinesia in man].

Wistar male rats received haloperidol (0.6 mg.kg-1, i.p.) and GABA-linoleamide (10 mg.kg-1, i.p.) and have been observed 120 or 240 minutes after administrations, during 2 minutes, in order to quantify oral dyskinesias (vacuous chewing movements, teeth chattering & grating) and catalepsy. It has been observed a significant potentiation of catalepsy with apparition of oral dyskinesias, in comparison with rats receiving only haloperidol. This phenomenon, probably due to the inhibition of the striato-nigral GABA-ergic pathway, could serve as an easy and reliable model for the human tardive dyskinesias dues to the chronic administration of neuroleptics. It could be complementary or be used in place of the actual models on rats and monkeys, which need neuroleptic administration during several months. Moreover oral dyskinesias, obtained with haloperidol and GABA-linoleamide, provide an additional argument on the role of the striato-nigral GABA-ergic pathway's failure in the pathogenesis of human tardive dyskinesias. Specific compensation of this failure could constitute a new therapeutic approach for tardive dyskinesias.

Animals↗
PubMed2000

Gamma-aminobutyric acid agonists for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Chronic antipsychotic drug treatment may cause tardive dyskinesia (TD), a long-term movement disorder. The gamma-aminobutyric acid (GABA) agonist drugs have been trialed as a treatment for TD, but these drugs have intense sedative properties and can possibly exacerbate psychotic symptoms. OBJECTIVES: To determine the effects of GABA agonist drugs (baclofen, gamma-vinyl-GABA, gamma-acetylenic-GABA, progabide, muscimol, sodium valproate and tetrahydroisoxazolopyridine (THIP)) in people with neuroleptic-induced tardive dyskinesia (TD) and schizophrenia or other chronic mental illnesses. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1998), The Cochrane Library CENTRAL (1998), Cochrane Schizophrenia Group's Register of Trials (1998), EMBASE (1980-1998), LILACS (1982-1996), MEDLINE (1966-1998), PsycLIT (1974-1998), and SCISEARCH were undertaken. References of all identified studies were searched for further trial citations. First authors of each included trial were contacted. SELECTION CRITERIA: The inclusion criteria for all relevant randomised studies were that they should focus on people with schizophrenia or other chronic mental illnesses, with neuroleptic-induced TD and compare the use of GABA agonist drugs to placebo or no intervention. DATA COLLECTION AND ANALYSIS: The reviewers extracted the data independently and the odds ratio (OR) and its 95% confidence interval (CI) or the weighted mean difference with 95% CI were estimated. The reviewers assumed that people who dropped out had no improvement. MAIN RESULTS: Eight studies were able to be included. Results were equivocal, showing only a tendency for clinical improvement for those using GABA agonist drugs but, when analysis of any improvement (rather than clinical improvement) was performed, a significant reduction was noted in the GABA group (OR 0.36 CI 0.15-0.85). This suggests that for every 10 people treated with GABA drugs one person would benefit with a reduction in TD symptoms. People using the interventions had more confusion (OR 7.4 CI 1.3-40.9) and sedation (OR 3.0 CI 1.2-7.6). The numbers of people needed to treat to cause one extra person to experience these side effects were three and six, respectively. Tendency for more deterioration of the TD symptoms (OR 1.72 CI 0. 54-5.5), deterioration of the mental state (OR 3.07 CI 0.78-12.05), and to drop out before the end of the trial (OR 2.05 CI 0.8-5.21) were also observed in those using GABA agonists. REVIEWER'S CONCLUSIONS: No clear statement about the efficacy of GABA agonist drugs could be provided. From the combined data, GABA agonist drugs tend to be associated with some degree of improvement in TD symptoms, but also with side effects such as confusion and sedation and a deterioration of the person's mental state.

Antipsychotic Agents↗
PubMed2000

Diltiazem, nifedipine, nimodipine or verapamil for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Tardive dyskinesia (TD) is a potentially disfiguring movement disorder of the orofacial region often caused by use of neuroleptic drugs. A wide range of strategies have been used to help manage TD and, for those who are unable to have their antipsychotic medication stopped or substantially changed, the calcium-channel blocking group of drugs (diltiazem, nifedipine, nimodipine, verapamil) has been suggested as a useful adjunctive treatment. OBJECTIVES: To determine the clinical efficacy of calcium-channel blockers in people with neuroleptic-induced tardive dyskinesia (TD) and schizophrenia or other chronic mental illnesses. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1995), Cochrane Schizophrenia Group's Register of trials (1995), EMBASE (1980-1995), LILACS (1982-1996), MEDLINE (1966-1995), PsycLIT (1974-1995), and SCISEARCH were undertaken. References of all identified studies were searched for further trial citations. Principal authors of trials were contacted. SELECTION CRITERIA: The inclusion criteria for all relevant randomised studies were that they should focus on people with schizophrenia or other chronic mental illnesses, with neuroleptic-induced TD and compare the use of calcium-channel blockers to placebo or no intervention. DATA COLLECTION AND ANALYSIS: No data could be extracted from the two randomised controlled trials that are currently awaiting assessment. The authors have been contacted to provide the relevant information. MAIN RESULTS: No studies met the entry criteria. No data were synthesized. REVIEWER'S CONCLUSIONS: Based on currently available information, no confident statement can be made about the effectiveness of calcium-channel blockers for treating people with neuroleptic-induced tardive dyskinesia. Before evaluation of these drugs in larger randomised controlled trials, clinicians should carefully weigh up their possible benefits against their potential adverse effects.

Antipsychotic Agents↗
PubMed1994

Suppression of dyskinesias in advanced Parkinson's disease: moderate daily clozapine doses provide long-term dyskinesia reduction.

Dyskinesias commonly appear during L-dihydroxyphenylalanine (L-DOPA) therapy of advanced Parkinson's disease (PD) and can occur in both dose-related and dose-independent patterns. Clozapine exerts a dose-related suppression of L-DOPA-induced dyskinesias by shifting the i.v. L-DOPA dose-response curve for production of dyskinesias without altering relief of parkinsonism. We report our outpatient experience with 13 patients on daily clozapine therapy (maximum dose 400 mg/day), followed for 3-21 months (median 10). Beneficial effects of clozapine, determined from twice-weekly diaries, included increased "on time" and decreased "off time" and time "on with dyskinesia." Improvements were statistically apparent by 75 mg/day and remained so through 200 mg/day. Sedation was a common problem, reflected by increased time "asleep" which was significant by 50 mg/day. Sedation was dose limiting in most patients. Orthostatic hypotension and sialorrhea were variably present. No patients had seizures, bone marrow toxicity, or detectable loss of efficacy of clozapine with chronic use. We conclude that clozapine is an effective agent for suppression of dyskinesias in PD with an effective daily dose for most patients of 100-200 mg/day.

Aged↗
PubMed1980

Spontaneous dyskinesias vs. neuroleptic-induced dyskinesias in 270 elderly subjects.

A comparative study of spontaneous dyskinesias and neuroleptic-induced dyskinesias was made in 270 elderly subjects of a retirement home in France. Females were found to have twice the incidence of dyskinesias (27%) than did males (12%) (p = .04). In addition, 18% of the patients who had not received neuroleptics had dyskinesias; however, 42% of those who had received neuroleptics had dyskinesias. This difference is significant at the p = .0001 level. These results are discussed in terms of the general phenomena of central nervous system degeneration in the elderly.

Aged↗
PubMed1993

Suppression of dyskinesias in advanced Parkinson's disease. I. Continuous intravenous levodopa shifts dose response for production of dyskinesias but not for relief of parkinsonism in patients with advanced Parkinson's disease.

We characterized the clinical dose-response curves for relief of parkinsonism and production of dyskinesias as a function of plasma levodopa and 3-O-methyldopa levels in six patients with advanced Parkinson's disease (PD) and fluctuating responses to oral levodopa/carbidopa. Dose response to ramped intravenous levodopa infusion was measured after overnight drug withdrawal on two occasions: first after chronic, intermittent oral levodopa/carbidopa, and second after 3 to 5 days of continuous intravenous levodopa. Continuous intravenous levodopa shifted the dyskinesia dose-response curve to the right, reduced maximum dyskinesia activity, but did not significantly alter dose response for relief of parkinsonism. Improvement in dyskinesia was apparent by the second day of continuous levodopa, during which ratios of plasma dopa/3-O-methyldopa remained constant. Our results support the hypothesis that relief of parkinsonism and production of dyskinesia by levodopa occur by separate mechanisms.

Aged↗
PubMed2000

Vitamin E for neuroleptic-induced tardive dyskinesia.

BACKGROUND: Neuroleptic (antipsychotic) medication is used extensively to treat people with chronic mental illnesses. However, it is associated with a wide range of adverse effects, including movement disorders such as tardive dyskinesia (TD). Vitamin E has been proposed as a treatment to prevent or decrease the severity of TD. OBJECTIVES: To determine the clinical effects of vitamin E for people with schizophrenia or other chronic mental illnesses who also developed neuroleptic-induced tardive dyskinesia. SEARCH STRATEGY: Electronic searches of Biological Abstracts (1982-1998), The Cochrane Schizophrenia Group's Register (September 1998), EMBASE (1980-98), LILACS (1982-96), MEDLINE (1966-98), PsycLIT (1974-98), SCISEARCH, handsearching the references of all identified studies and contacting the first author of each included trial. SELECTION CRITERIA: Reports identified in the search were included if they were controlled trials dealing with people with neuroleptic-induced TD and schizophrenia or other chronic mental illness who had been randomly allocated to either vitamin E or to a placebo or no intervention. DATA COLLECTION AND ANALYSIS: Data were independently extracted from these trials by each reviewer and Peto odds ratios (OR) or average differences, with the 95% confidence intervals (CI) were estimated. The reviewers assumed that people who dropped out had no improvement. MAIN RESULTS: Eight studies were included, and another three are currently awaiting further data from authors. The overall results for both, 'clinically relevant improvement' and 'any improvement' of TD symptoms, were in favour of vitamin E (OR 0.16, CI 0.04-0.7, NNT 5 CI 2.-32 and OR 0.23, CI 0.10-0.55, NNT 4 CI 2. 5-12 respectively). People who had not used vitamin E showed more deterioration of their symptoms (OR 0.20, CI 0.04-0.93). No difference could be found regarding the presence of adverse effects or leaving the study early before the end of study. There is no trial-based information regarding the effect of vitamin E for those with early onset of TD. REVIEWER'S CONCLUSIONS: Small trials with uncertain quality of randomisation, tend to suggest that vitamin E improves the symptoms of TD. Methodological problems such as small sample size, short term interventions, and inappropriate use of crossover design need to be dealt with in any future studies. The results of a recently completed trial involving 158 participants are eagerly awaited.

Antipsychotic Agents↗
PubMed1989

Anatomically distinct output channels of the caudate nucleus and orofacial dyskinesia: critical role of the subcommissural part of the globus pallidus in oral dyskinesia.

The findings in this feline study indicate that the enkephalin-positive subcommissural part of the globus pallidus, which is known to contain GABA and cholinergic cells projecting to the cortex, is innervated by the anterodorsal region of the caudate nucleus, but not by the core. Like stimulation of a particular subclass of dopamine receptors in the anterodorsal region of the caudate nucleus, inhibition of the GABA receptors in the noted part of the globus pallidus resulted in orofacial dyskinesia, viz. tic-like contractions of the facial, eye and ear muscles, and tongue protrusions. This phenomenon was elicited by intrapallidal injections of the GABA antagonist picrotoxin in a dose-dependent manner and could be attenuated by the GABA agonist muscimol. Previous studies have already shown that neither stimulation of the dopamine receptors in the core of the caudate nucleus nor any manipulation with the first- and second-order output-stations of the latter brain region, viz. (a) those regions of the substantia nigra, pars reticulata which receive afferents from the caudate nucleus, and (b) those regions of the intermediate layers of the superior colliculus which receive afferents from the latter nigral region, ever resulted in orofacial dyskinesia. These findings support the hypothesis that the anatomically distinct input-output channels of the caudate nucleus are differentially involved in orofacial dyskinesia. The clinical impact of these findings is discussed in view of the L-3,4-dihydroxyphenylalanine-induced tardive dyskinesia in man. In addition, the relevance of the anatomical data is discussed in view of the co-occurrence of Parkinson's Disease and Dementia of Alzheimer-type in certain patients.

Animals↗
PubMed1993

Suppression of dyskinesias in advanced Parkinson's disease. II. Increasing daily clozapine doses suppress dyskinesias and improve parkinsonism symptoms.

We gave increasing daily doses of clozapine to six patients with advanced Parkinson's disease (PD) and levodopa-induced dyskinesias. Clozapine reduced the daily dyskinesia time five-fold, increased "on" time eight-fold, and doubled the serum [DOPA] producing half-maximal dyskinesia. Parkinsonism scores after overnight DOPA withdrawal improved with increasing daily clozapine intake, and there was no clozapine dose-related shift in levodopa dose response for relief of parkinsonism. Patients experienced sedation, sialorrhea, and orthostatic hypotension. Clozapine appears to be an effective agent for suppression of levodopa-induced dyskinesias in PD.

Aged↗