Acute extrapyramidal side effects: serum levels of neuroleptics and anticholinergics

Cell-based serum anticholinergic activity assay and working memory in cognitively healthy older adults before and after scopolamine: An exploratory study

BACKGROUND

A new cell-based serum anticholinergic activity (cSAA) assay that measures anticholinergic activity specifically at muscarinic M1 receptors and eliminates many of the drawbacks of the existing assay was developed by our team.

AIMS

We aimed to study the relationship between changes in working memory and executive function with changes in cSAA using the new assay in cognitively healthy older adults.

METHODS

Cognitively healthy participants aged 50 years and above, received a single dose of 0.4 mg of intravenous scopolamine. Cognition and cSAA levels were measured before and 30 min after receiving scopolamine. Cognition was measured using the Cambridge Neuropsychological Test Automated Battery.

RESULTS

Ten participants were recruited, and nine (mean age = 69.8, SD = 9.5, range 59-86 years) completed the study. Following scopolamine, participants experienced an increase in cSAA (cSAA pre = 0.90 ± 0.97 vs cSAA post = 12.0 ± 3.70 pmol/L; t-test (df = (8) = -9.5, p < 0.001). In addition, there was an association between change in cSAA and changes in working memory (Spearman's ρ = 0.68, p = 0.042) and executive function (Spearman's ρ = 0.72, p = 0.027).

CONCLUSIONS

In our sample of cognitively healthy older adults, the new cSAA assay was able to quantify the scopolamine induced increase in anticholinergic load which correlated significantly with the observed decline in working memory and executive function.

Novel insights into the interaction between long non-coding RNAs and microRNAs in glioma

Glioma is the most common brain tumor of the central nervous system. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs) have been identified to play a vital role in the initiation and progression of glioma, including tumor cell proliferation, survival, apoptosis, invasion, and therapy resistance. New documents emerged, which indicated that the interaction between long non-coding RNAs and miRNAs contributes to the tumorigenesis and pathogenesis of glioma. LncRNAs can act as competing for endogenous RNA (ceRNA), and molecular sponge/deregulator in regulating miRNAs. These interactions stimulate different molecular signaling pathways in glioma, including the lncRNAs/miRNAs/Wnt/β-catenin molecular signaling pathway, the lncRNAs/miRNAs/PI3K/AKT/mTOR molecular signaling pathway, the lncRNAs-miRNAs/MAPK kinase molecular signaling pathway, and the lncRNAs/miRNAs/NF-κB molecular signaling pathway. In this paper, the basic roles and molecular interactions of the lncRNAs and miRNAs pathway glioma were summarized to better understand the pathogenesis and tumorigenesis of glioma.

Higher levels of α7 nicotinic receptors, but not choline acetyltransferase, in the dorsolateral prefrontal cortex from a sub-group of patients with schizophrenia

It has been suggested the study of sub-groups within the syndrome of schizophrenia will assist in elucidating the complex pathophysiology of the syndrome. Hence, we have studied a number of cholinergic markers in the cortex from a sub-group of subjects with schizophrenia that have a marked decrease in levels of muscarinic M1 receptors (MRDS). The displacement of [³H]NMS by cortical extracts was used to measure tissue anticholinergic load, [¹²⁵I]α bungarotoxin binding was used to measure levels of the α7 nicotinic receptor (CHRNA7) and western blotting was used to measure levels of choline acetyltransferase (ChAT) 68 and 82 as well as synaptosome nerve-associated protein 25 (SNAP25). In comparing schizophrenia, MRDS and non-MRDS to controls, there were no differences in levels of ChAT 68 or 82, SNAP 25 or cholinergic load in BA 9. However, levels of CHRNA7 were higher in BA 9, but not BA 6 or 44, from subjects with MRDS. These data argue that there is no change in cholinergic innovation (measured using ChAT), presynaptic neurons (measured using SNAP25) or cholinergic load in schizophrenia, MRDS or non-MRDS. However, increased levels of CHRNA7 may be contributing to a breakdown in cholinergic homeostasis in BA 9, but not BA 6 or 44, in subjects with MRDS.

Serum anticholinergicity is associated with reduced prefrontal brain function in early course schizophrenia

Increased anticholinergic activity resulting from pharmacotherapies used to treat schizophrenia is associated with poorer cognition. However the neural mechanisms underlying this effect are unknown. In this study of 39 early course schizophrenia outpatients, we demonstrate that increased serum anticholinergic activity is associated with reduced activation across the prefrontal cortex, including the dorsolateral, anterior, and medial prefrontal cortices, during two tasks of cognitive control. Lower activation in the dorsolateral and anterior prefrontal cortices mediated the association between increased anticholinergicity and poorer neurocognitive function. Such findings provide preliminary insight into how anticholinergic medications may impact cognition through reduced prefrontal cortical function in schizophrenia.

An improved, high-efficiency assay for assessing serum anticholinergic activity using cultured cells stably expressing M1 receptors

Assessments of total anticholinergic activity (SAA) in serum are of considerable interest for its potential involvement in cognitive impairment associated with polydrug states in the elderly and other populations. Such estimations have been based on the displacement of radioligand binding in rat brain tissues. The validity of such measurements has been questioned, as a potentially distorting effect of large serum proteins was identified. We sought to develop a modified assay that would be more efficient and free of this potential confound. Cultured CHO cells stably expressing M1 receptors M1WT3 were used. Binding of ³H-radioligands was conducted in 96-well plates and tested in serum containing known amounts of anticholinergic medications. Effects of endogenous serum proteins were assessed by pre-assay filtration and also by deproteinization with perchloric acid (PCA). Binding of [³H]quinuclidinyl benzilate ([³H]QNB) or [³H]N-methyl-scopolamine ([³H]NMS) to M1WT3 cells proved reliable and equally sensitive to varying concentrations of anticholinergic agents. In agreement with previous findings (Cox, Kwatra, Shetty, & Kwatra, 2009), filtration of proteins heavier than 50kDa essentially reduced SAA values to zero. In contrast, PCA preserved more than 70% of the binding seen untreated cell membranes. Cell-based assays also showed significant signal increases compared to the conventional rat brain-based protocol. Further advantages of the cell-based protocol described here include increased sensitivity and reliability, smaller amounts of radioligand needed, and higher throughput. PCA pretreatment eliminates potential artifacts attributable to serum proteins. This step, together with improvements in efficiency, should contribute significantly to the usefulness of the assay.

Prefrontal gray matter morphology mediates the association between serum anticholinergicity and cognitive functioning in early course schizophrenia

Antipsychotic and other medications used in the treatment of schizophrenia place a burden on the cholinergic subsystems of the brain, which have been associated with increased cognitive impairment in the disorder. This study sought to examine the neurobiologic correlates of the association between serum anticholinergic activity (SAA) and cognitive impairments in early schizophrenia. Neurocognitive performance on measures of memory and executive function, structural magnetic resonance imaging (MRI) scans, and SAA assays were collected from 47 early course, stabilized outpatients with schizophrenia or schizoaffective disorder. Voxel-based morphometry analyses employing general linear models, adjusting for demographic and illness-related confounds, were used to investigate the associations between SAA, gray matter morphology, and neurocognitive impairment. SAA was related to working memory and executive function impairments. Higher SAA was significantly associated with lower gray matter density in broad regions of the frontal and medial-temporal lobes, including the dorsolateral prefrontal cortex (DLPFC), hippocampus, and striatum. Lower gray matter volume in the left DLPFC was found to significantly mediate the association between SAA and working memory impairment. Disease- and/or medication-related cholinergic dysfunction may be associated with brain volume abnormalities in early course schizophrenia, which may account for the association between SAA and cognitive dysfunction in the disorder.

Impact of anticholinergics on the aging brain: a review and practical application

Objective: in an effort to enhance medication prescribing for older adults and reduce the burden of cognitive impairment, this paper reviews the literature regarding the negative impact of anticholinergics on cognitive function and provides clinicians with a practical guidance for anticholinergic use in older adults. Methods: a Medline search identified studies evaluating the use of anticholinergics and the relationship between anticholinergics and cognitive impairment. Results: prescribing anticholinergics for older adults leads to acute cognitive impairment and, possibly, chronic cognitive deficits. Assessing anticholinergic burden with a simple scale may represent a useful noninvasive tool to optimize geriatric pharmacotherapy. Conclusion: more studies are needed to validate the Anticholinergic Cognitive Burden scale and establish therapeutic guidelines in the presence of cognitive anticholinergic adverse effects.

A model of anticholinergic activity of atypical antipsychotic medications

BACKGROUND

Atypical antipsychotics clozapine, olanzapine, and quetiapine have significant affinity for the muscarinic receptors in vitro, while aripiprazole, risperidone, and ziprasidone do not. Dissimilarity in binding profiles may contribute to the reported differences in the anticholinergic effects of these antipsychotics. However, it is difficult with the available data to predict the likelihood of anticholinergic effects occurring with various doses of an atypical antipsychotic.

METHODS

We developed a model to assess the potential anticholinergic activity (AA) of atypical antipsychotics at therapeutic doses. A radioreceptor assay was used to measure in vitro AA at 6 clinically relevant concentrations of aripiprazole, clozapine, olanzapine, quetiapine, risperidone, and ziprasidone. Using published pharmacokinetic data, in combination with the measured in vitro AA, dose-AA curves were generated.

RESULTS

Clozapine, and to a lesser extent olanzapine and quetiapine showed dose-dependent increases in AA. At therapeutic doses, the AA (in pmol/mL of atropine equivalents) was estimated to range from 27-250, 1-15, and 0-5.4 pmol/mL for clozapine, olanzapine, and quetiapine, respectively. Aripiprazole, risperidone, and ziprasidone did not demonstrate AA at any of the concentrations studied.

CONCLUSIONS

Therapeutic doses of clozapine, olanzapine, and, to a lesser extent, quetiapine are associated with clinically relevant AA.

Drugs with anticholinergic properties and cognitive performance in the elderly: results from the PAQUID Study

OBJECTIVES

To measure the association between the use of drugs with anticholinergic properties and cognitive performance in an elderly population, the PAQUID cohort.

METHODS

The sample studied was composed of 1780 subjects aged 70 and older, living at home in South western France. Data on socio-demographic characteristics, medical history and drug use were collected using a standardized questionnaire. Cognitive performance was assessed using the following neuropsychological tests: the Mini-Mental State Examination (MMSE) which evaluates global cognitive functioning, the Benton Visual Retention Test (BVRT) which assesses immediate visual memory, and the Isaacs' Set Test (IST) which assesses verbal fluency. For each test, scores were dichotomized between low performance and normal to high performance using the score at the 10th percentile of the study sample as the cut-off point, according to age, gender and educational level. The association between the use of drugs with anticholinergic properties and cognitive performance was examined using logistic regression models, adjusting for several potential confounding factors.

RESULTS

About 13.7% of the subjects used at least one drug with anticholinergic properties. In multivariate analyses, the use of these drugs was significantly associated with low performance in the BVRT [odds ratio (OR) = 1.6; 95% confidence interval (CI) 1.1, 2.3] and in the IST (OR = 1.9; 95% CI 1.3, 2.8). The association found with low performance in the MMSE (OR = 1.4; 95% CI 1.0, 2.1) was barely statistically significant.

CONCLUSION

These findings suggest that the use of drugs with anticholinergic properties is associated with low cognitive performance among community-dwelling elderly people.

Serum antimuscarinic activity during clozapine treatment

This study attempts: (1) to verify that serum antimuscarinic activity is related to clozapine dose, and more importantly to clozapine plasma concentrations; (2) to explore whether norclozapine has serum antimuscarinic activity; (3) to explore whether antimuscarinic activity is related to clozapine side effects; and (4) to compare the serum antimuscarinic activities of clozapine with those of antiparkinsonian drugs and other antipsychotics. In 39 patients participating in a double-blind clozapine study, the [3H]QNB assay was used to measure serum antimuscarinic activity: (1) on baseline medications; (2) after a 4-week haloperidol trial; (3) after a 16-week clozapine trial of either 100, 300, or 600 mg/d; and (4) after 1 or 2 consecutive 16-week clozapine trials with remaining doses in nonresponders. Clozapine levels predicted serum antimuscarinic activity better than clozapine dose. At the end of the 1st clozapine trial, the correlation with the levels explained 69% of the variance of serum antimuscarinic activity (r = 0.83, P < 0.001, N = 34). Clozapine levels were good predictors of serum antimuscarinic activity only in patients taking 300 or 600 mg/d. After correcting for clozapine levels, the within-subject correlation between norclozapine levels and serum antimuscarinic activity was relatively high and significant (r = 0.54, F = 26.7, df = 1.65, P < 0.001). Constipation was significantly associated with higher serum antimuscarinic activity during the 1st clozapine trial. Clozapine was associated with clearly higher antimuscarinic activity than other antipsychotics or low doses of antiparkinsonians. In vitro studies and new clinical studies are needed to verify whether norclozapine may significantly contribute to antimuscarinic activity during clozapine treatment.

Antipsychotic drug-induced movement disorders

Very early in the process of diagnosing abnormal involuntary movement (AIM) disorders, one can be rewarded by keeping a high index of suspicion for possible drug-induced causes, not only through a complete list of current medications, but also identification of the drugs the patient used to take and other possible offending medications that might be available from family members and other sources. Among drug-induced movement disorders, antipsychotic drugs and other dopamine receptor blocking agents occupy a central place. Their various acute and tardive motor complications provide the template of this short review. Movement disorders caused by antidepressants, lithium, antiemetics, antiparkinsonian agents, anticonvulsants, calcium channel blockers, sympathomimetics and others are only briefly covered in table form.

Antipsychotic radioreceptor assay: a modification identifying selective receptor effects

Radioreceptor assays offer the advantage of a single assay that can assess uniform exposure to multiple chemical compounds. The advent of atypical antipsychotic agents has led to new awareness of the multiple receptor subtypes through which antipsychotic agents may exert their effects, and a renewed interest in comparative drug trials of antipsychotics. The objective of this study was to show the development and validation of antipsychotic radioreceptor assays using clonal cell lines stably expressing isolated human receptors. Model assays were developed using the dopamine(2) (D(2)) and D(4) receptors. D(2) and D(4) activities measured by radioreceptor assay in plasma of antipsychotic-treated subjects were highly correlated with high-performance liquid chromatography determinations of antipsychotic concentrations. Similarly, for a variety of typical and atypical antipsychotic agents, the quotients of D(4)/D(2) activity in plasma of antipsychotic-treated subjects were highly correlated with the quotients of D(4)/D(2) affinities of these agents. Valid receptor-selective antipsychotic assays can be established and may have utility for dissecting the in vivo activity of atypical antipsychotics in relation to specific outcomes in clinical trials.

Anticholinergicity and cognitive processing in chronic schizophrenia

Patients with chronic schizophrenia suffer from alterations in cholinergic functioning due to several factors, including the disease diathesis and pharmacologic treatments. Acetylcholine-cognition relationships are well explored in normals but are unclear in schizophrenia. Prior work indicated serum anticholinergicity does not cause global cognitive impairment in this group (Tracy et al., 1998a), raising the possibility that anticholinergicity normalizes an abnormal hyperactive cholinergic state. Serum anticholinergic levels were determined in 38 chronic schizophrenia patients using an established radioreceptor assay method. Six cognitive functions associated with cholinergic tone in normals were tested. The potential role of autonomic arousal and cigarette smoking were also assessed as both have been linked to cholinergic functioning. Regression analyses showed measures of inhibitory executive control and effortful memory accounted for a greater proportion of the variance in the anticholinergicity measure compared to the other variables. The data demonstrate a relationship between high anticholinergicity and worse performance on two types of attention-resource demanding cognitive processes and do not support the notion that reduced cholinergic tone normalizes a hyperactive cortical acetylcholine substrate. Relevant neuroanatomic structures and implications for models of cognitive deficits in schizophrenia are discussed.

Therapeutic effects of imipramine are counteracted by its metabolite, desipramine, in patients with generalized anxiety disorder

Imipramine has been shown to reduce anxiety in patients with generalized anxiety disorder (GAD). However, some properties of imipramine may diminish or counteract its anxiolytic effects. The authors previously found that the greater the reduction in cardiac vagal control after 6 weeks of imipramine treatment, the smaller the improvement in anxiety-related symptoms. The purpose of this study was to determine whether the authors' previous findings were replicable and to gather information on the plasma levels of imipramine, desipramine (the major metabolite of imipramine), and anticholinergic levels. Fourteen patients with GAD were administered imipramine for 6 weeks. Their scores from self-administered and investigator-administered rating scales were obtained before and after the treatment, and the changes in these scores were contrasted with the changes in cardiac vagal tone, along with the absolute plasma levels of imipramine, desipramine, and anticholinergic activity at the end of week 6. The authors observed a greater improvement in symptoms of anxiety in those who showed the smallest decreases in cardiac vagal tone and in those who showed the smallest increases in desipramine and anticholinergic plasma levels. Moreover, strong relationships were observed between desipramine and anticholinergic levels. These results demonstrate that imipramine not only has therapeutic effects, but it may also have properties that result in physiologic states that counteract its therapeutic effects. Future research should investigate the direct anticholinergic effects of desipramine and determine whether there is a parallel between the anticholinergic effects and the clinical outcome of other pharmacologic treatments, including antidepressants with predominantly norepinephrine or serotonin reuptake inhibitory properties.

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.

Anticholinergic differences among patients receiving standard clinical doses of olanzapine or clozapine

This study evaluated anticholinergic effects among patients with schizophrenia, schizoaffective disorder, or bipolar I disorder who were receiving either olanzapine (N = 12) or clozapine (N = 12) at standard clinical doses in a naturalistic setting. Serum anticholinergic levels were determined in adult male and female subjects using a radioreceptor binding assay. The Udvalg for Kliniske Undersogelser Scale was used to evaluate anticholinergic side effects clinically, and the Mini-Mental State Examination provided a global cognitive measure. Patients had achieved target doses that were stable at the time at which blood samples were obtained, and no other concomitant medicine with known anticholinergic potential was allowed. Patients receiving olanzapine (average dose, 15 mg/day) had serum anticholinergic levels of 0.96 (+/-0.55) pmol/ atropine equivalents compared with levels of 5.47 (+/-3.33) pmol/atropine equivalents for those receiving clozapine (average dose, 444 mg/day) (p < 0.001). Rates of increased and decreased salivation were significantly more common among the clozapine- and olanzapine-treated patients, respectively, whereas constipation, urinary disturbances, and tachycardia/palpitations were significantly more common among clozapine-treated patients. Neither group showed any global cognitive deficits. Olanzapine-treated patients had serum anticholinergic levels that were less than one fifth those of the clozapine-treated patients. Furthermore, clinical evaluations confirmed that clozapine-treated patients experienced more frequent and severe anticholinergic side effects (except dry mouth). However, none of the patients in either group expressed any desire to discontinue these medications as a result of the anticholinergic side effects.

Managing antipsychotic-induced acute and chronic akathisia

Akathisia is a frequent and common adverse effect of treatment with antipsychotic (neuroleptic) drugs. This syndrome consists of subjective (feeling of inner restlessness and the urge to move) as well as objective components (rocking while standing or sitting, lifting feet as if marching on the spot and crossing and uncrossing the legs while sitting). Antipsychotic-induced akathisia can be classified according to the time of onset in the course of antipsychotic treatment (acute, tardive, withdrawal and chronic akathisia). Reported prevalence rates vary widely between 5 and 36.8%. Numerous risk factors for acute akathisia have been described and the exact pathophysiology of akathisia is still unknown. Since akathisia is a drug-induced adverse effect, optimal management involves its prevention rather than treatment. Standardised titration and the use of novel antipsychotics are successful measures of prevention. This paper reviews different forms of therapeutic approaches for the treatment of akathisia. Based on the available literature, propranolol or other lipophilic beta-blockers seem to be the most consistently effective treatment for acute akathisia. There is nothing in the literature to guide a clinician when treatment with beta-blockers fails. Addition of benzodiazepines would appear to be a sensible next choice, especially if subjective distress persists. If all of these drugs are unsuccessful, amantadine or clonidine can be tried. Other agents that have been investigated include ritanserin, piracetam, valproic acid (sodium valproate) and tricyclic antidepressants. Evidence on the treatment of tardive akathisia is unsatisfactory.

Importance of serum anticholinergic activity in the assessment of elderly patients with delirium

To evaluate the importance of serum anticholinergic activity (SAA) in elderly patients who developed delirium following hospital admission, we performed a cross-sectional study with consecutively referred inpatients in a university geriatric medical ward. Sixty-one patients aged 66 to 95 years (mean age: 79.2+/-11.6; 54% females) were recruited. Delirium was assessed by means of the Confusion Assessment Method, SAA determination, questionnaire for current drug treatment, past medical history and clinical examination, and blood chemistries. Patients were divided into two groups according to the absence (N = 49) or the presence (N = 12) of delirium. Delirious patients showed a significantly higher SAA (23.0 vs 3.9 pmol/mL atropine equivalents, P < .004); they were using antibiotics (P < .05), neuroleptics (P < .002), barbiturates (P < .004), and benzodiazepines (P < .005) more frequently. Subjects with delirium were more likely to have infections and a lower Body Mass Index; they had higher plasma glucose and creatinine. The multivariate analysis identified SAA and use of neuroleptics, and benzodiazepines as the most important features independently associated with delirium. SAA may be a suitable marker for identifying people at risk of developing delirium. Moreover, neuroleptics and benzodiazepines must be carefully used in the elderly because of their relationship with the onset of delirium.

The influence of ondansetron and m-chlorophenylpiperazine on scopolamine-induced cognitive, behavioral, and physiological responses in young healthy controls

BACKGROUND

There is evidence from animal and human experiments that learning and memory come under the separate influence of both cholinergic and serotonergic pathways. We were interested in learning whether serotonergic drugs could attenuate or exacerbate the memory-impairing effects of anticholinergic blockade in humans.

METHODS

The selective serotonin 5-HT3 receptor antagonist ondansetron (0.15 mg/kg i.v.) and the serotonergic agent m-chlorophenylpiperazine (m-CPP; 0.08 mg/kg i.v.) were administered in combination with the anticholinergic agent scopolamine (0.4 mg PO) and compared to scopolamine alone in 10 young, healthy volunteers. Testing occurred on three separate days.

RESULTS

As expected, i.v. administration of scopolamine induced significant impairments in episodic memory and processing speed; however, these scopolamine-induced cognitive deficits were not attenuated by pretreatment with i.v. ondansetron (0.15 mg/kg), nor were they exacerbated by administration of i.v. m-CPP (0.8 mg/kg) in addition to scopolamine; however, administration of i.v. m-CPP was followed by a significant increase of self-rated functional impairment, altered self-reality, and dysphoria ratings, and scopolamine's effect on pupil size was potentiated.

CONCLUSIONS

Together, these results suggest that in young, healthy volunteers scopolamine-induced changes of cognitive performance are only minimally modulated by the serotonergic effects on ondansetron and m-CPP. Further studies with older controls are needed to test whether these findings may be influenced by age.

Neuroleptic-Induced Parkinsonism in Elderly Patients Diagnosed With Psychotic Major Depression and Dementia of the Alzheimer Type

The authors prospectively examined elderly patients diagnosed with major depression with psychotic features (MD-P) and patients diagnosed with dementia of the Alzheimer Type (DAT) for neuroleptic-induced parkinsonism (NIP) during perphenazine treatment. Baseline parkinsonian symptoms did not differ between groups. With treatment, mean NIP score doubled in DAT patients but remained unchanged in the MD-P group. The difference between groups was highly significant and remained so after the effects of age, perphenazine dose, and duration of perphenazine treatment were controlled. Although the mechanisms underlying these differences in NIP development remain to be determined, clinical guidelines for neuroleptic dosages in elderly patients need to account for variability in neuroleptic tolerance between diagnostic groups.

Usage and Side Effects of Neuroleptics in Elderly Japanese Patients

The authors assessed the use and side effects of neuroleptics (especially tardive dyskinesia [TD]) in elderly patients in Japan (N = 73; mean age 76 years, 32 men and 41 women) admitted for the first time to six psychiatric hospitals. The comparison group was 74 elderly patients with dementia admitted to nursing homes or psychiatric hospitals and not treated with neuroleptics. The mean dose of neuroleptics in the Japanese elderly patients was lower than that in Western countries; however, the prevalence of side effects was higher, possibly because of polypharmacy. The total number of psychotropic drugs correlated significantly with the number of side effects. Incidence of dyskinesia in the patients treated with neuroleptics (for a mean of 20 months) was significantly greater (44%) than that in non-neuroleptic-treated patients (14%). A significant risk factor for TD was long-term neuroleptic therapy, whereas age, gender, psychiatric diagnosis, neuroleptic dose, and antiparkinsonian drug use were not risk factors.

Phase I and II metabolites of benztropine in rat urine and bile

Following oral administration of benztropine (IO mg/kg, body weight), the phase I metabolites, benztropine N-oxide, N-desmethylbenztropine, tropine, 4'-hydroxybenz- tropine, N-desmethyl-4'-hydroxybenztropine, 4'-hydroxvbenztropine N-oxide and methoxy-4'-hydroxybenztropine, together with unmetabolized benztropine, were isolated and identified in rat urine and bile by GC-electron impact mass spectrometry (EI GC/MS), microcolumn LC-electrospray mass spectrometry (ES LC/MS) and hplc followed by MS analysis. The mass spectra and chromatographic properties of isolated N-desmethylbenztropine, benztropine N-oxide and tropine were confirmed by comparison with authentic reference standards. Sufficient quantities of 4'-hydroxybenztropine and N-desmethyl-4'-hydroxybenztropine were isolated from the urine by tlc and examined by 1H-nmr, ES/MS and EI/MS. The structure of the methoxy-4'-hydroxybenztropine metabolite was determined by EI/MS. 4'-Hydroxybenztropine N-oxide was identified by reacting it with a reducing agent, titanous chloride, to form 4'-hydroxybenztropine, which was then confirmed by comparing its EI/MS and ES/MS behaviour with a previously isolated and 1H-nmr-authenticated sample. In addition, four intact glucuronide conjugates of benztropine were also characterized in bile and urine as phase II metabolites, including 4'-O-glucuronylbenzotropine, N-desmethyl-4'-O-glucuronylbenztropine, methoxy-4'-O-glucuronylbenztropine and 4'- O-glucuronylbenztropine N-oxide by hplc followed by ES/MS analysis. These results provide the first direct evidence of the presence of these metabolites of benztropine in rat.

Serotonergic modulation of anticholinergic effects on cognition and behavior in elderly humans

Cholinergic neurotransmission is thought to be modulated by serotonin as documented in animal and human studies. We examined the effects of the muscarinic antagonist scopolamine (0.4 mg IV) given alone or together with the serotonin mixed agonist/antagonist m-chlorophenylpiperazine (m-CPP, 0.08 mg/kg IV), and the selective 5-HT3 receptor antagonist ondansetron (0.15 mg/kg IV). Ten normal elderly volunteers each received five separate pharmacologic challenges (placebo, ondansetron, scopolamine, scopolamine+ondansetron, and scopolamine+m-CPP). Cognitive, behavioral, and physiologic variables were analyzed using repeated measures analysis of variance. The acute effects of scopolamine in certain cognitive, behavioral, and physiological measures were significantly exaggerated by the addition of m-CPP. Scopolamine's cognitive effects were unaffected by ondansetron at the dose tested, nor did ondansetron given alone affect basal cognitive performance. This pilot study suggests that the serotonin mixed agonist/antagonist m-CPP may influence cholinergic neurotransmission. The changes associated with the combination of scopolamine and m-CPP do not appear to be secondary to simple pharmacokinetic alterations and suggest a complex interaction between the cholinergic and serotonergic systems centrally.

Serum anticholinergic activity in hospitalized older persons with delirium: a preliminary study

OBJECTIVE

To evaluate the relationship between total serum anticholinergic activity (SAA) and the presence or absence of delirium in older hospitalized persons on general medical wards.

DESIGN

Case-control study and within-subjects repeated-measures in recovered delirious patients.

SETTING

Minneapolis Veterans Affairs Medical Center medical wards.

PARTICIPANTS

Eleven male delirious patients (DSM-III-R criteria) aged 60 or older and 11 comparably aged male nondelirious controls.

MEASUREMENTS

Radioreceptor bioassay of total SAA using tritiated quinuclidinyl benzilate (QNB) binding to muscarinic receptors. Results are expressed in terms of atropine equivalents (nM).

MAIN RESULTS

Mean SAA was significantly elevated in the delirious group (mean +/- SD = 6.05 +/- 2.97 nM atropine equivalents) compared with the controls (3.38 +/- 2.49; t(20) = 2.28, P < .05). At study entry, mean SAA was significantly higher in delirious subjects whose symptoms eventually resolved completely (mean +/- SD = 7.77 +/- 2.37) compared with subjects whose delirious symptoms persisted (3.99 +/- 2.30; t(9) = 2.68, P < .05). All six patients in whom delirium resolved completely had a decrease in serum anticholinergic activity when measured during delirium (7.77 +/- 2.37) and after symptom resolution (3.92 +/- 2.61; t(5) = 3.29, P < .05).

CONCLUSIONS

Our findings suggest that serum anticholinergic activity may play a role in delirium in medical inpatients. The relationships between SAA and delirium in medical patients and between total SAA and medication use warrant further study.

Oculogyric spasm in Asian psychiatric in-patients on maintenance medication

BACKGROUND

The objective was to investigate the occurrence and characteristics of oculogyric spasm (OGS) in an Asian country.

METHOD

All 2035 Asian (88% Chinese, 7% Malays and 5% Indonesians) psychiatric in-patients in the state psychiatric hospital in Singapore were surveyed for occurrence of oculogyric spasm (OGS) over a two-month period.

RESULTS

Thirty-four patients (1.7%) developed OGS (53% male and 47% female). All the 34 patients had been on maintenance antipsychotic drugs for more than five months. Eighteen patients had recurrent attacks. The mean chlorpromazine equivalent daily dose for those patients with recurrent OGS was 511 mg. This was significantly higher (P < 0.05) than the 277 mg daily dose received by those without recurrent OGS. Most (68%) of the attacks occurred between 1400-2000 h suggesting that OGS may have a diurnal variation.

CONCLUSIONS

OGS presenting as tardive dystonia may be due to a relative increase in cholinergic activity.

Motor and mental aspects of acute extrapyramidal syndromes

Acute extrapyramidal syndromes (EPS) are one of the major limitations to effective neuroleptic treatment. These disorders have both motor (objective) and mental (subjective) aspects, which must be considered in any evaluation and differential diagnosis of treatment-related side effects. The disorders of akathisia, acute dystonia and parkinsonism have unique features that are best understood in the context of a careful assessment of patient characteristics, drug factors and temporal aspects. Though acute EPS are commonly explained on the basis of dopamine D2 receptor antagonism, data from several lines of study raise important questions about this hypothesis. The roles of receptor subtype specificity, brain region selectivity and ratios of different receptor subtype antagonism are discussed. New and novel antipsychotic drugs with low rates of EPS are important clinical advancements that will increase patients' ability to participate in therapy and rehabilitation and thus improve their quality of life.

Treatment of schizophrenia: a clinical and preclinical evaluation of neuroleptic drugs

Forty years after the first clinical report on the effectiveness of chlorpromazine in psychiatric patients, neuroleptic drugs are still the most widely used drugs in the treatment of schizophrenia. Indeed, there are no other drugs which have proven to be as effective in the treatment of this severe psychiatric disorder. Yet, there are still many unresolved problems relating to neuroleptic drugs. The present review gives a comprehensive overview of our knowledge (and our lack of knowledge) with respect to the clinical and preclinical effects of neuroleptic drugs and tries to integrate this knowledge in order to identify the neuronal mechanisms underlying the therapeutic and side effects of neuroleptic drugs.

Neuroleptic drug-induced extrapyramidal syndromes and tardive dyskinesia

Neuroleptic (antipsychotic) drug-induced acute extrapyramidal syndromes (EPS) and the late onset tardive dyskinesia (TD) are the major side effects that limit the use of these highly efficacious agents. The appropriate strategy for controlling these side effects is based on the clinical presentations, pathophysiological mechanisms, and contributions of patient and treatment-related risk factors. New information about the mechanisms of action of neuroleptics and the long-term outcome of acute EPS and TD provide valuable insights into these syndromes. The most effective method for maximizing the benefits and minimizing the risks of neuroleptics is to use the lowest effective dose of both neuroleptic and antiEPS drugs in patients who benefit from them. The next major advancement will be to develop new compounds which effectively control psychotic symptoms and are free of the undesirable acute and tardive motor syndromes.

Anticholinergic serum levels and cognitive performance

Integrity of central cholinergic neurotransmission is essential for adequate cognitive functioning. Many psychotherapeutic medications have anticholinergic side-effects. In order to determine the impact of circulating anticholinergic activity on cognitive performance, 28 geropsychiatric inpatients underwent cognitive testing at different levels of anticholinergic serum activity. In 10 subjects with a diagnosis of probable Alzheimer's disease, significant deterioration of selected cognitive functions was observed at anticholinergic serum levels that caused no dysfunction in the 18 non-demented subjects. The data suggest that non-demented elderly patients with psychiatric problems tolerate psychotropic pharmacotherapy without significant negative impact on their cognitive competency. By contrast, patients with Alzheimer's disease are at risk of additional impairment. The introduction of anticholinergic serum activity as a monitoring technique for safe psychopharmacotherapy in geriatric patients is discussed.

Difference in catalepsy response in inbred rats during chronic haloperidol treatment is not predictive of the intensity of behavioral hypersensitivity which subsequently develops

An animal model was utilized to explore the observed clinical association between a history of significant neuroleptic-induced parkinsonism and an increased incidence for the subsequent development of tardive dyskinesia. Catalepsy-sensitive Fisher rats and catalepsy-resistant Brown Norway rats were treated for 14 days with haloperidol at a dose of either 1 mg/kg or 5 mg/kg daily. Following a 7-day drug withdrawal period, rats were tested for behavioral hypersensitivity to acute challenge with apomorphine and then striata were assayed for 3H-spiroperidol receptor binding. Despite significant interstrain difference in catalepsy response to either neuroleptic dose, Brown Norway rats treated with 5 mg/kg developed behavioral hypersensitivity and D-2 receptor supersensitivity equivalent to that of the similarly treated Fisher rats. Catalepsy, a possible rat analog for neuroleptic-induced parkinsonism, therefore did not predict the intensity of those subsequent behavioral and receptor changes considered to result from chronic antagonism of striatal dopamine receptors and to possibly underlie tardive dyskinesia. Further studies are required to elucidate the less than obvious relationship between extrapyramidal behavioral effects of chronic neuroleptic treatment.

Relationship between extrapyramidal symptoms and serum anticholinergic levels in treated chronic schizophrenics

Serum anticholinergic levels were measured by radioreceptor assay (RRA) in schizophrenic patients treated for drug-induced Parkinsonism; 68 patients stabilized on a single neuroleptic and an anticholinergic antiparkinsonian agent (benzhexol, benztropine or procyclidine) were assessed using the extrapyramidal side effects (EPS) scale prior to each blood sampling. Serum anticholinergic levels showed a significant inverse correlation with EPS but did not appear to be dose-related in any of the three anticholinergic drug groups. Percentage binding to proteins was significantly less with benztropine than either benzhexol or procyclidine. Serum-free anticholinergic levels correlated significantly with total serum levels in the benzhexol and procyclidine groups but not in the benztropine group. At serum levels above 4.5 pmol/ml atropine equivalents, EPS was significantly less than at levels below that. We discuss the implications of this finding and suggest practical clinical applications of measurement of serum anticholinergic levels. Serum neuroleptic and serum prolactin levels did not correlate with either dose or serum level of anticholinergics.

Neuroleptic side effects: acute extrapyramidal syndromes and tardive dyskinesia

The neuroleptic-induced motor system side effects of acute extrapyramidal syndromes (EPS) and tardive dyskinesia (TD) are the major limitations of these drugs. Effective strategies for managing these problems are based on the clinical presentations, pathophysiological processes, and a complex interaction of patient and treatment variables. New concepts about the causes and long-term outcome of acute EPS and TD are emerging to challenge some of the commonly held views about these syndromes. The primary method of preventing undue side effects is to use the lowest effective dose of both neuroleptic and anti-EPS drugs. The pressing need is for novel compounds which treat schizophrenia and are free of the undesirable motor system effects (a nonneuroleptic neuroleptic).

Unusual treatment response of a severe dystonia to diphenhydramine

A 27-year-old man was admitted to the emergency department with a fluphenazine decanoate-induced dystonia. He was treated with 125 mg diphenhydramine IV in four doses and 2 mg benztropine IM. A fluctuating response was observed before continued remission of the dystonia. Possible reasons for variable patient responses to diphenhydramine are discussed.

Plasma level monitoring of antipsychotic drugs. Clinical utility

The steady-state plasma concentrations of antipsychotic drugs show large interpatient variations but remain relatively stable from day to day in each individual patient. Monitoring of antipsychotic drug concentrations in plasma might be of value provided the patients are treated with only 1 antipsychotic drug. Some studies have reported a relationship between therapeutic response and serum antipsychotic drug 'concentrations' as measured using the radioreceptor assay (RRA) method, which measures dopamine receptor-blocking activity in plasma. Most studies, however, have failed to demonstrate such a relationship, and the RRA does not seem to provide the generally useful tool for plasma concentration monitoring of antipsychotic drugs that was hoped for initially. A lack of correlation between dopamine receptor-blocking activity in plasma and therapeutic response may be due to differences in the blood-brain distribution of both antipsychotic drugs and their active metabolites. Chemical assay methods (e.g. GLC and HPLC) have been used in studies which examined the relationships between therapeutic response and antipsychotic drug concentrations in red blood cells and in plasma. It seems that for these drugs, measuring red blood cell concentrations does not offer any significant advantage over measuring plasma concentrations. Reasonably controlled studies of plasma concentration-response relationships using randomly allocated, fixed dosages of chlorpromazine, fluphenazine, haloperidol, perphenazine, sulpiride, thioridazine and thiothixene have been published but often involve relatively few patients. A correlation between therapeutic response and plasma concentrations of thioridazine and its metabolites has not been demonstrated, and plasma level monitoring of thioridazine and its metabolites therefore appears to have no clinical value. Clinical behavioural deterioration concomitant with high plasma concentrations of chlorpromazine and haloperidol have been reported. A dosage reduction might be considered after 2 to 4 weeks' treatment in non-responders who have plasma chlorpromazine concentrations above 100 to 150 micrograms/L or plasma haloperidol concentrations above 20 to 30 micrograms/L. Non-responders and good responders to chlorpromazine treatment, however, have plasma drug concentrations in the same range, and a therapeutic range of plasma chlorpromazine levels has not been defined. Therapeutic plasma haloperidol concentrations (i.e. 'window') in the range of 5 to 20 micrograms/L have been reported by some investigators, but others have found no such relationship.(ABSTRACT TRUNCATED AT 400 WORDS)

Pharmacokinetics of trihexyphenidyl after short-term and long-term administration to dystonic patients

Although trihexyphenidyl has been used effectively for many years in the treatment of Parkinson's disease, little is known about its pharmacokinetics. Using a sensitive radioreceptor assay for anticholinergic drugs, we assayed trihexyphenidyl in human serum and studied its pharmacokinetics following short-term and long-term administration to patients with dystonia. Previously untreated patients had a biphasic semilogarithmic plot of serum concentration-time consisting of an initial rapid distribution phase and a later slower elimination phase. Patients on long-term treatment showed only the slower elimination phase. Elimination followed first-order kinetics and was rapid, with a half-life of 3.7 +/- 0.4 (SEM) hours. There was no relationship between half-life and peak serum level, age, duration of therapy, or etiology or severity of dystonia. Although acute anticholinergic side effects paralleled the rise and fall of serum anticholinergic levels, the response of dystonia did not.

Mental dysfunction and the blockade of muscarinic receptors in the brains of the normal elderly

Cholinergic neurons innervate many areas of the brain and the disruption of acetylcholine neurotransmission at the muscarinic receptors in these areas produces dysfunction in a wide variety of mental, emotional and physiological activities. A side effect of many psychoactive drugs is the blockade of muscarinic receptors and this can result in a marked reduction of acetylcholine neural function particularly in elderly patients receiving 2 or more such drugs, and mimic the mental impairments seen in Alzheimer's Disease. A battery of mental status and short term memory tests was given the day before and 45 minutes after the administration of 0.005 mg/kg scopolamine or saline as presurgery medication to 30 normal patients over 60 years of age scheduled for lower body surgery. Total antimuscarinic activity was determined using a competitive binding assay in a 10 ml sample of blood taken from all patients after the pretest and again at the time of surgery, and in a 2 ml sample of cerebral spinal fluid taken from patients receiving spinal anesthesia immediately prior to administering the anaesthetic. The very low dose of scopolamine given to these patients produced antimuscarinic activity equivalent to 100 pmoles atropine in serum and 74 pmoles atropine in CSF. This resulted in a significant impairment of short term memory but had no significant effect on global scores on the Mini Mental State nor on the Delirium Check List.

Lateral ventricular size and drug-induced Parkinsonism

Computed Tomography (CT) was used to assess lateral ventricular size in 20 psychiatric inpatients who had participated in at least 5 weeks of a fixed dose chlorpromazine (CPZ) trial. During treatment with CPZ, eight patients had required antiparkinsonian medication for treatment of rigidity. The ventricular brain ratio (VBR) of these eight patients was greater than that of either the 12 patients who did not require antiparkinsonian medication or a similarly aged control group of neurological patients, scanned for tension or migraine headaches. On the basis of these findings it is suggested that large lateral ventricular size may be associated with increased vulnerability to develop drug-induced parkinsonism.