Drugs with anticholinergic properties: a current perspective on use and safety

Introduction: Many commonly used drugs have primary or secondary anticholinergic effects contributing to adverse outcomes ranging from mild-to-severe to potentially lethal. Anticholinergic adverse effects frequently occur with medications prescribed with other intended mechanisms of action, including antihistamines, antidepressants, and antipsychotics. Anticholinergic drugs are also the principal treatments of clinical conditions, such as urinary incontinence, that tend to occur in the elderly. Older patients and those with mental illness are particularly vulnerable to the adverse neuropsychiatric effects of anticholinergics as they may already have cognitive impairment.

Areas covered: Medline and Pubmed literature searches (1966 – the present) were performed using ‘anticholinergic’ and ‘drug safety’. Abstracts were assessed and references scanned for appropriate articles. Here, the authors i) describe the neural pathways of the cholinergic system; ii) outline the main clinical uses and adverse effects of anticholinergic agents with a focus on cognitive impairment; and iii) discuss anticholinergic safety monitoring.

Expert opinion: Prescribers need to be vigilant for adverse anticholinergic effects, particularly in older patients. The symptoms may range from subtle cognitive impairment to delirium and may be due to the cumulative effect of multiple medications of modest antimuscarinic activity. The Anticholinergic Drug Scale and tables listing drugs with known anticholinergic properties may help in guiding clinical decision-making to reduce anticholinergic burden.     

Anticholinergic Drug Burden in Older People's Brain – How well is it Measured?

Concurrent use of several drugs with potential anticholinergic properties is highly prevalent in the elderly. Methods to determine the overall anticholinergic drug burden have been developed to estimate the risk of central anticholinergic adverse effects. The objective of this MiniReview was to critically appraise the clinical utility of the methods used to assess the anticholinergic drug burden in older people's brain. We evaluated the in vitro method used to measure the anticholinergic activity in a patient's serum and the four anticholinergic drug scales: Anticholinergic Risk Scale, Anticholinergic Cognitive Burden, Drug Burden Index and Anticholinergic Drug Scale. Medline searches of the literature from January 1988 to January 2013 were performed. Studies that related anticholinergic drug burden to central adverse outcomes in elderly people were included, while case reports and studies of single substances were excluded. Despite the consistently reported association between a high anticholinergic drug burden and negative cognitive and psychomotor outcomes in older patients, there are discrepancies in the literature. Furthermore, no significant cognitive improvements after the anticholinergic drug burden was reduced have been shown in randomized controlled trials. It is reasonable to question whether the estimated anticholinergic drug burden can predict the overall brain effects of multiple anticholinergic agents in older people.     

Drug-induced cognitive impairment in the elderly.

Elderly people are more likely than younger patients to develop cognitive impairment as a result of taking medications. This reflects age- and disease-associated changes in brain neurochemistry and drug handling. Delirium (acute confusional state) is the cognitive disturbance most clearly associated with drug toxicity, but dementia has also been reported. The aetiology of cognitive impairment is commonly multifactorial, and it may be difficult to firmly establish a causal role for an individual medication. In studies of elderly hospital patients, drugs have been reported as the cause of delirium in 11 to 30% of cases. Medication toxicity occurs in 2 to 12% of patients presenting with suspected dementia. In some cases CNS toxicity occurs in a dose-dependent manner, often as a result of interference with neurotransmitter function. Drug-induced delirium can also occur as an idiosyncratic complication. Finally, delirium may occur secondary to iatrogenic complications of drug use. Almost any drug can cause delirium, especially in a vulnerable patient. Impaired cholinergic neurotransmission has been implicated in the pathogenesis of delirium and of Alzheimer's disease. Anticholinergic medications are important causes of acute and chronic confusional states. Nevertheless, polypharmacy with anticholinergic compounds is common, especially in nursing home residents. Recent studies have suggested that the total burden of anticholinergic drugs may determine development of delirium rather than any single agent. Also, anticholinergic effects have been identified in many drugs other than those classically thought of as having major anticholinergic effects. Psychoactive drugs are important causes of delirium. Narcotic agents are among the most important causes of delirium in postoperative patients. Long-acting benzodiazepines are the commonest drugs to cause or exacerbate dementia. Delirium was a major complication of treatment with tricyclic antidepressants but seems less common with newer agents. Anticonvulsants can cause delirium and dementia. Drug-induced confusion with nonpsychoactive drugs is often idiosyncratic in nature, and the diagnosis is easily missed unless clinicians maintain a high index of suspicion. Histamine H2 receptor antagonists, cardiac medications such as digoxin and beta-blockers, corticosteroids, non-steroidal anti-inflammatory agents and antibiotics can all cause acute, and, less commonly, chronic confusion. Drug-induced confusion can be prevented by avoiding polypharmacy and adhering to the saying 'start low and go slow'. Special care is needed when prescribing for people with cognitive impairment. Early diagnosis of drug-induced confusion, and withdrawal of the offending agent or agents is essential.     

Concurrent use of anticholinergic drugs and cholinesterase inhibitors: register-based study of over 700,000 elderly patients

BACKGROUND: Although cholinesterase inhibitors are used for the treatment of Alzheimer's disease, the clinical benefits of these drugs are being questioned. Anticholinergic drugs have the opposite pharmacological action to cholinesterase inhibitors, and may antagonize the effects of cholinesterase inhibitors. Therefore, this drug combination should be avoided. Nevertheless, high rates of concurrent use of anticholinergic drugs and cholinesterase inhibitors have been reported in the US. To the authors' knowledge, use of this inappropriate drug combination has not been studied outside North America. OBJECTIVE: To investigate (i) whether anticholinergic drug use is more common among users than non-users of cholinesterase inhibitors, and (ii) which factors are associated with use of anticholinergic drugs among users of cholinesterase inhibitors. METHODS: We analysed data on age, sex, type of residential area (urban/rural) and drugs dispensed for patients aged >/=75 years registered in the Swedish Prescribed Drug Register from October to December 2005 (n = 731 105). The prevalence of use of anticholinergic drugs in users of cholinesterase inhibitors was compared with that in non-users of cholinesterase inhibitors and logistic regression was used to study the association between use of cholinesterase inhibitors and anticholinergic drugs. Logistic regression was also used to analyse whether age, sex, type of residential area or number of dispensed drugs was associated with use of anticholinergic drugs among users of cholinesterase inhibitors (n = 18 326). RESULTS: Anticholinergic drug use was more common among cholinesterase inhibitor users than non-users, particularly in men, of whom 9% who were taking cholinesterase inhibitors were dispensed anticholinergic drugs compared with 5% who were not taking cholinesterase inhibitors. Use of cholinesterase inhibitors was associated with use of anticholinergic drugs in men (odds ratio 1.23; 95% CI 1.13, 1.35), after adjustment for age, type of residential area and number of dispensed drugs. Male sex and use of many drugs were independently associated with concurrent use of anticholinergic drugs and cholinesterase inhibitors. CONCLUSION: Anticholinergic drug use is more common among cholinesterase inhibitor users than non-users, even though anticholinergic drugs may antagonize the effect of cholinesterase inhibitors. Hence, if the true clinical effects of cholinesterase inhibitors are to be accurately assessed, they need to be studied in the absence of anticholinergic drugs.     

Anticholinergic burden and risk of cognitive impairment in elderly nursing home residents with depression

BackgroundAlthough the adverse cognitive effects of anticholinergic medications in the elderly are well-documented, little is known regarding the cognitive impact of anticholinergics among nursing home residents with depression.ObjectiveThis study examined the risk of mild-to-moderate cognitive impairment due to anticholinergic burden among elderly nursing home residents with depression.MethodsA population-based nested case-control study was conducted using Minimum Data Set (MDS)-linked Medicare data where the base cohort included patients ≥ 65 years with depression who had intact cognition (MDS Cognition score of 0 or 1) and no dementia. Cases were identified as those who had mild-to-moderate cognition (MDS Cognition score of 2–4). Each case was matched on age and sex to one control using incidence density sampling. The study evaluated cumulative anticholinergic burden (defined as score of 3 or more) within 30, 60 and 90 days preceding the event date based on the Anticholinergic Drug Scale (ADS). Conditional logistic regression model stratified on matched case-control sets was performed to evalaute cognitive impairment due to cumulative anticholinergic burden after controlling for other risk factors.ResultsThe study sample included 3707 cases with mild-to-moderate cognition and 3707 matched controls with intact cognition. Bivariate analysis showed significant association between cumulative anticholinergic exposure and cognitive impairment (Odds Ratio [OR], 1.15; 95% Confidence Interval [CI],1.04–1.30); after controlling for potential risk factors, cumulative anticholinergic exposure 30 days preceding the event was no longer associated with cognitive impairment, (aOR, 1.07; 95% CI, 0.95–1.21). However, the odds of cognitive impairment increased with cumulative anticholinergic exposure 60 days (aOR 1.16; 1.04–1.30) and 90 days (aOR 1.28; 1.14–1.44) before the event date.ConclusionCumulative anticholinergic use for prolonged exposure periods was associated with modestly increased risk of cognitive impairment in elderly residents with depression who had intact cognition. The findings suggest the need to be cautious when prescribing multiple anticholinergic drugs in residents, including those with intact cognition.     

Paying attention to pharmacokinetic and pharmacodynamic mechanisms to progress in the area of anticholinergic use in geriatric patients

Many naturalistic studies agree that adverse drug reactions (ADRs), particularly cognitive deficits, frequently occur when medications with anticholinergic activity are used in geriatric patients. However, the studies disagree on which anticholinergic drugs may have clinical relevance. The three most important methods to establish clinically relevant anticholinergic activity are: 1) the drug's affinity for muscarinic receptors, demonstrated by in vitro studies and a profile compatible with antagonist properties; 2) serum anticholinergic activity measured by radioreceptor assay; and 3) the presence of typical antimuscarinic ADRs, such as dry mouth and constipation, in patient studies or clinical trials. More recently, brain imaging of muscarinic receptors and scales for quantifying antimuscarinic activity were developed. A comprehensive approach can be crafted only by paying attention to the pharmacodynamic and pharmacokinetic mechanisms of these drugs. ADR studies on drugs with anticholinergic activity should not only consider central muscarinic receptor blockade, but also peripheral receptor blockade. The ability to cross the blood-brain barrier is important in the drug's ADR profile. Patient personal characteristics, drug-drug interactions (DDIs) and probably genetic variations may contribute to increased ADR risk through pharmacokinetic and/or pharmacodynamic mechanisms. Sophisticated clinical designs and the evidence-based medicine approach cannot succeed unless the list of drugs of anticholinergic activity is agreed upon, and the studies include a sophisticated pharmacological approach guided by our current understanding of their pharmacodynamic and pharmacokinetic mechanisms. If one agrees that antimuscarinic ADRs are probably dose-related, future studies must consider all drugs, administration routes, doses, muscarinic receptor affinity, DDIs, and brain access.     

Potential adverse effects of bronchodilators in the treatment of airways obstruction in older people: recommendations for prescribing

Asthma and chronic obstructive pulmonary disease (COPD) are common disorders that are associated with increasing morbidity and mortality in older people. Bronchodilators are used widely in patients with these conditions, but even when used in inhaled form can have systemic as well as local effects. Older people experience more adverse drug effects because of pharmacodynamic and pharmacokinetic changes and particularly drug-drug and drug-disease interactions. Cardiovascular disease is common in older people and beta-adrenoceptor agonists (beta-agonists) have inotropic and chronotropic effects that can increase arrhythmias and cardiomyopathy. They can also worsen or induce myocardial ischaemia and cause electrolyte disturbances that contribute to arrhythmias. Tremor is a well known distressing adverse effect of beta-agonist administration. Long-term beta-agonist use can be associated with tolerance, poor disease control, sudden life-threatening exacerbations and asthma-related deaths. Functional beta2-adrenoceptors are present in osteoblasts, and chronic use of beta-agonists has been implicated in osteoporosis. Inhaled anticholinergics are usually well tolerated but may cause dry mouth, which can be troublesome in older people. Pupillary dilatation, blurred vision and acute glaucoma can occur from escape of droplets from loosely fitting nebulizer masks. Although ECG changes have not been seen in randomized controlled trials of long-acting inhaled anticholinergics, supraventricular tachycardias have been observed in a 5-year randomized controlled trial of ipratropium bromide. Paradoxical bronchoconstriction can occur with inhaled anticholinergics as well as with beta-agonists, but tolerance has not been reported with anticholinergics. Anticholinergic drugs also cause central effects, most notably impairment of cognitive function, and these effects have been noted with inhaled agents. Use of theophylline is limited by its adverse effects, which range from commonly occurring gastrointestinal symptoms to palpitations, arrhythmias and reports of myocardial infarction. Seizures have been reported, but are rare. Theophylline is metabolized primarily by the liver, and commonly interacts with other medications. Its concentration in plasma should be monitored closely, especially in older people. Although many clinical trials have been conducted on bronchodilators in obstructive airways disease, the results of these clinical trials need to be interpreted with caution as older people are often under-represented and subjects with co-morbidities actively excluded from these trials.     

Prevalence of anticholinergic burden and risk factors amongst the older population: analysis of insurance claims data of Korean patients

Background Despite growing interest in the negative clinical outcomes of multiple anticholinergic use, limited studies have evaluated anticholinergic burden in the geriatric population nationally. Objective To evaluate the prevalence of high anticholinergic burden using the newly developed Korean Anticholinergic Burden Scale in comparison with previous tools and to identify associated factors. Setting National insurance data from a cross section (20%) of older Koreans (2016). Methods Anticholinergic burden was measured using the Korean scale in comparison to the Anticholinergic Drug Scale, Anticholinergic Cognitive Burden, and Anticholinergic Risk Scale. High anticholinergic burden was defined as a summed score of ≥?3 for concurrent medications or a dose-standardized average daily score of ≥?3, using each anticholinergic scale. Main outcomes measured Prevalence and predictors of high anticholinergic burden. Results Data of 1,292,323 patients were analyzed. According to the Korean scale, the prevalence of high anticholinergic burden was 25.5%. This result was similar to that from the Anticholinergic Drug Scale (24.9%) and Anticholinergic Cognitive Burden (22.2%). Factors associated with an increased likelihood of anticholinergic burden include: age, gender (female), high Charlson comorbidity index score, polypharmacy, medical aid beneficiary, co-morbidities (such as schizophrenia, depression, urinary incontinence, and Parkinson’s disease), frequent healthcare visits, various healthcare facilities utilized, and predominantly visiting hospital-level facilities. According to the Korean Anticholinergic Burden Scale, the major drugs contributing to the anticholinergic burden were ranitidine, chlorpheniramine, tramadol, and dimenhydrinate. Conclusion This study showed that 1 in 4 older Koreans are exposed to high anticholinergic burden. The predictors identified in this research might assist pharmacists in early interventions for their patients.

     

Anticholinergics: theoretical and clinical overview

ABSTRACT

Introduction: Anticholinergics are a class of medicines that block the neurotransmitter, acetylcholine, in the brain and peripheral tissues. Medicines with anticholinergic activity are widely prescribed for and used by older people for various medical conditions. One-third to one-half of the medicines commonly prescribed for older people have anticholinergic activity. Several studies have reported anticholinergic burden to be a predictor of cognitive and functional impairments in older people.

Areas covered: This article exemplifies the theoretical and clinical aspects of medicines with anticholinergic activity, including pharmacology (definition of medicines that possess anticholinergic activity, antimuscarinic receptors, therapeutic and adverse effects), epidemiology, measures and effects of cumulative anticholinergic burden in older adults, and clinical recommendations. In addition, the gaps in the literature have been identified for future research.

Expert opinion: Many medicines that are commonly prescribed to older people have a degree of anticholinergic activity that can contribute to anticholinergic burden. Anticholinergic burden, measured in several ways that consider number, dose and/or degree of anticholinergic activity of medicines, has shown to be a predictor of adverse health and functional outcomes. The anticholinergic burden on older people should be minimised by avoiding, reducing dose and deprescribing medicines with anticholinergic activity where clinically possible.     

Antipsychotic medications and the elderly: effects on cognition and implications for use

Despite being frequently prescribed in the elderly, antipsychotic medications are commonly associated with adverse effects in this population, including sedative, orthostatic and extrapyramidal adverse effects. Growing evidence suggests that antipsychotics can also cause deleterious cognitive effects in some elderly patients. Preclinical and growing clinical evidence indicates that inhibitory effects on dopaminergic, cholinergic and histaminergic neurochemical systems may account for antipsychotic-associated cognitive impairment in the elderly. A review of published reports of the cognitive effects of antipsychotics in the elderly suggests that newer antipsychotic medications may possess a more favourable cognitive profile than that of traditional agents in this population. The cognitive effect that a specific antipsychotic will have in the elderly, however, is likely better predicted by considering the pharmacodynamic action of an individual agent in combination with the pathophysiology of the condition being treated. Agents with relatively weak dopamine inhibiting effects (e.g. clozapine and quetiapine), for example, would theoretically have a cognitive profile superior to that of agents with higher degrees of dopaminergic inhibition (all traditional agents, risperidone, olanzapine and ziprasidone) when used for conditions associated with diminished dopamine function (e.g. idiopathic Parkinson's disease). Drugs with weak anticholinergic effects (high-potency traditional agents, risperidone, quetiapine and ziprasidone) would theoretically be less likely to cause cognitive impairment than agents with high degrees of cholinergic receptor blocking actions (clozapine and olanzapine) when treating patients with impaired cholinergic function (e.g. Alzheimer's disease). Cholinergic agonist effects of clozapine and olanzapine may, however, mitigate potential adverse cognitive effects associated with the cholinergic blocking actions of these agents. Large, rigorous trials comparing the cognitive effects of antipsychotics with diverse pharmacodynamic actions are lacking in the elderly and are needed.     

Transdermal oxybutynin: a review

Overactive bladder is a common and disabling problem. The mainstay of pharmacological treatment is with oral anticholinergic drugs. Anticholinergic side effects are common and include dry mouth and constipation. Compliance is limited by these side effects. Transdermal administration of oxybutynin has been shown to be as effective as oral treatment while minimising the anticholinergic side effects. Skin reactions occur frequently, necessitating changes of application site. Despite this, the preparation is a useful element in the armamentarium to treat overactive bladder. It is likely to be particularly useful in those in whom side effects of oral medication are intolerable or in whom oral administration of drug is not possible. Here, the pharmacokinetics, pharmacodynamics, efficacy and safety of transdermal oxybutynin are reviewed.     

Anticholinergic Activity of Psychotropic Drugs and Cognitive Impairment Among Participants Aged 45 and Over: The CONSTANCES Study

Introduction

Psychotropic drugs such as anxiolytics, antidepressants and antipsychotics may have anticholinergic properties that could directly affect patients’ cognition.

Objectives

Our objective was to assess the relationship between exposure to anticholinergic-positive (AC+) psychotropic drugs and cognitive impairment compared with psychotropic drugs without anticholinergic activity (AC−).

Methods

This analysis included participants (aged 45–70 years) enrolled between January 2012 and October 2017 in the CONSTANCES cohort treated with psychotropic drugs (antidepressants n = 2602, anxiolytics n = 1195, antipsychotics n = 197) in the 3 years preceding cognitive assessment. Within each drug class, the Anticholinergic Cognitive Burden scale was used to classify drugs as either AC+ or AC−. Cognitive impairment was defined as a score below − 1 standard deviation from the standardized mean of the neuropsychological score. We used multiple logistic regression models and matching on propensity score to estimate the relationship between anticholinergic activity and cognitive impairment.

Results

Our analyses did not show any increased risk of cognitive impairment for AC+ antidepressants and anxiolytics, with the exception of a slight increase for AC+ antidepressants in episodic memory (odds ratio [OR] 1.19; 95% confidence interval [CI] 1.05–1.36). Conversely, we found a more marked increase in risk with AC+ antipsychotics on executive function (Trail Making Test-A [TMT-A], OR 4.49 [95% CI 2.59–7.97] and TMT-B, OR 3.62 [95% CI 2.25–5.89]).

Conclusion

Our results suggest there is no clinically relevant association between the anticholinergic activity of antidepressant and anxiolytic drugs and cognitive impairment in middle-aged adults. An association could exist between AC+ antipsychotics and executive function.

     

A critical appraisal of the utility of the serum anticholinergic activity assay in research and clinical practice

The serum anticholinergic activity (SAA) assay was originally designed to quantify the anticholinergic burden of drug exposure. The same assay has been used to measure the anticholinergic activity of standard drug solutions. There are limitations to the use of the assay in research and in applying these findings to clinical practice. Assays of standard drug solutions do not account for pharmacokinetic differences among drugs, which limits the interpretation of such measurements. In addition, emerging evidence has suggested that anticholinergic medications may not be the only cause of elevated SAA. Despite these limitations, elevated SAA has been consistently associated with cognitive impairment and delirium in a number of research settings. Such findings have prompted investigators to consider the potential application of the SAA assay in research and in clinical practice. Therefore, the objectives of this review are to summarize the current literature involving the SAA assay, describe the relative merits and shortfalls of the SAA assay as a research tool, and discuss the potential for use of the SAA assay as a clinical tool.     

Drugs with anticholinergic effects and cognitive impairment,falls and all-cause mortality in older adults: A systematic review and meta-analysis

AimThe aim was to investigate associations between drugs with anticholinergic effects (DACEs) and cognitive impairment, falls and all-cause mortality in older adults.MethodsA literature search using CINAHL, Cochrane Library, Embase and PubMed databases was conducted for randomized controlled trials, prospective and retrospective cohort and case-control studies examining the use of DACEs in subjects ≥65 years with outcomes on falls, cognitive impairment and all-cause mortality. Retrieved articles were published on or before June 2013. Anticholinergic exposure was investigated using drug class, DACE scoring systems (anticholinergic cognitive burden scale, ACB; anticholinergic drug scale, ADS; anticholinergic risk scale, ARS; anticholinergic component of the drug burden index, DBI_AC) or assessment of individual DACEs. Meta-analyses were performed to pool the results from individual studies.ResultsEighteen studies fulfilled the inclusion criteria (total 124 286 participants). Exposure to DACEs as a class was associated with increased odds of cognitive impairment (OR 1.45, 95% CI 1.16, 1.73). Olanzapine and trazodone were associated with increased odds and risk of falls (OR 2.16, 95% CI 1.05, 4.44; RR 1.79, 95% CI 1.60, 1.97, respectively), but amitriptyline, paroxetine and risperidone were not (RR 1.73, 95% CI 0.81, 2.65; RR 1.80, 95% CI 0.81, 2.79; RR 1.39, 95% CI 0.59, 3.26, respectively). A unit increase in the ACB scale was associated with a doubling in odds of all-cause mortality (OR 2.06, 95% CI 1.82, 2.33) but there were no associations with the DBI_AC (OR 0.88, 95% CI 0.55, 1.42) or the ARS (OR 3.56, 95% CI 0.29, 43.27).ConclusionsCertain individual DACEs or increased overall DACE exposure may increase the risks of cognitive impairment, falls and all-cause mortality in older adults.     

Anticholinergics in the era of atypical antipsychotics: short-term or long-term treatment?

Anticholinergic agents are usually prescribed to prevent or treat antipsychotic-induced extrapyramidal symptoms. Their long-term benefits are questionable and they carry diverse adverse effects, including cognitive impairment and worsening of tardive dyskinesia. This literature review explores the impact of anticholinergic medication discontinuation on movement disorders, cognition and psychopathology in patients receiving antipsychotics. Medline, Embase and PsycInfo were searched from 1950 to July 2011 using "cessation /withdrawal /discontinuation /stopping" with "anticholinergic*" or "antiparkinson*" and "neuroleptic*" or "antipsychotic*". Additional articles were obtained by searching the bibliographies of relevant references. Earlier studies of anticholinergic agent discontinuation in patients receiving first-generation antipsychotics reported relapse rates of extrapyramidal symptoms between 4% and 80%, reflecting the heterogeneity of the studies. Two recent studies of patients prescribed second-generation antipsychotics obtained relapse rates of 4% and 33%. Some studies suggest improvement in tardive dyskinesia with cessation of anticholinergics. Four studies examined the effects of anticholinergic agent discontinuation on cognition and all observed an improvement post-discontinuation. Changes in symptoms of schizophrenia with anticholinergic discontinuation are conflicting, with more recent studies suggesting an improvement. Given their questionable benefit with continued use, clinicians should consider a gradual withdrawal of anticholinergic agents in stable patients receiving antipsychotics.     

Effects of cocaine on extracellular dopamine and serotonin levels in the nucleus accumbens

RATIONALE: Prepulse inhibition (PPI) of the startle response refers to an attenuation in response to a strong stimulus (pulse) if this is preceded shortly by a weak non-startling stimulus (prepulse). Patients with schizophrenia have repeatedly been found to show reduced PPI when compared to healthy people. Anticholinergic drugs are often used to control extrapyramidal symptoms induced by antipsychotic medication in schizophrenic patients. Antipsychotic medication, in particular with atypical drugs, has been shown to improve a range of cognitive functions and normalize PPI deficits in schizophrenia, whereas anticholinergic drugs disrupt cognitive functions in both normal and schizophrenic populations and also impair PPI in experimental animals. No previous study has investigated the effects of anticholinergic drugs on human PPI. OBJECTIVES: This study determined the effects of procyclidine, an anticholinergic drug, on PPI in healthy male volunteers, employing a double-blind placebo-controlled cross-over design. METHODS: Subjects underwent testing for PPI on two occasions: once after the oral administration of a placebo and once after the oral administration of procyclidine in two separate experiments. Experiment 1 examined the effects of 10 mg procyclidine, whereas experiment 2 examined the effects of 15 mg procyclidine. RESULTS: Procyclidine at a 10 mg dose, as compared to placebo, had no effect on PPI, but caused impairments at a 15 mg dose. In both experiments, procyclidine reduced response amplitude over the pulse-alone trials and heart rate 1-2 h post-administration. CONCLUSIONS: PPI of the human acoustic startle response is modulated by procyclidine. The use of anticholinergics needs to be considered in PPI studies in schizophrenia.     

Analysis of rapid heart rate variability in the assessment of anticholinergic drug effects in humans

Anticholinergic agents have widespread therapeutic indications in clinical medicine. In addition, certain other drug groups–such as neuroleptics, antidepressants and antihistamines–possess distinct anticholinergic properties that reduce tolerance and compliance. Especially in patients with heart disease, attention should be paid to cardiac anticholinergic drug effects. The analysis of short-term heart rate variability (HRV) provides a noninvasive tool to estimate vagal cholinergic outflow. In this review article, we present the basic principles of the most relevant techniques to study rapid HRV: the time domain analysis methods RMSSD and pNN50, and the high-frequency (HF) spectral component of HRV. We provide examples of previously reported effects of anticholinergic agents on these measures and also describe how adrenergic drugs may influence them. We have the following recommendations for a clinical pharmacologist investigating anticholinergic agents. (1) If the breathing rate of the study subject can be controlled during the assessment and the electrocardiogram recordings contain good-quality, stationary segments that are at least a few minutes long, then the HF power of HRV should be the method of choice. (2) During uncontrolled conditions, RMSSD should be included in the analyses, because it is less affected by changes in the respiratory pattern and it can be measured from shorter segments of electrocardiogram data. (3) Reduced short-term HRV suggests an anticholinergic, but not necessarily an antimuscarinic drug effect, since the inhibition of cholinergic vagal efferent activity may also originate from central or peripheral adrenergic influences.     

Seizures in elderly patients with dementia: epidemiology and management

Epileptic seizures occur in patients with dementia at a higher prevalence than among healthy elderly individuals. The incidence of seizures among patients with dementia varies with the aetiology of the dementing illness. In patients with Alzheimer's disease (the most common form of dementia), approximately 10-22% have at least one unprovoked seizure. Seizures usually occur in later stages of Alzheimer's disease, on average, > or =6 years into the course of the disease. Seizures in Alzheimer's disease are more likely to occur with early-onset disease, particularly if there is a familial presenilin I mutation. The incidence of seizures in other dementing diseases is less clear. There are special considerations regarding the management of seizures in the elderly with dementia. First, the presence of cognitive impairment may impede an accurate diagnosis of seizures. Clinicians may also mistake seizure manifestations for symptoms of the underlying dementia. Second, since most dementia patients are elderly, there are pharmacokinetic changes with aging that affect the use of antiepileptic drugs. Third, antiepileptic drugs have potential cognitive adverse effects that may worsen dementia. Although few studies are available, extrapolations from research in young people and elderly patients without dementia provide several recommendations for the management of seizures in patients with dementia: exclude symptomatic causes of seizures before committing to antiepileptic drug therapy; treat after a first seizure if there is evidence of focal neurological involvement or a risk of recurrent seizures; use antiepileptic drugs with minimal cognitive adverse effects, such as carbamazepine, valproic acid, gabapentin and lamotrigine; and use the lowest possible dosage and monitor antiepileptic drug levels, where possible.     

Anticholinergic burden risk and prevalence of medications carrying anticholinergic properties in elderly cancer patients in Jordan

BackgroundGeriatric cancer patients are susceptible to adverse drug events due to the complexity of their chemotherapy regimens and collateral treatments for their comorbid conditions. Prescribing medications with anticholinergic burden characteristics can complicate their condition, leading to negative impacts on their health outcomes and quality of life, including an increase in adverse drug event frequency, physical and cognitive impairments.ObjectiveThis study aims to examine the prevalence of anticholinergic prescribing and identify the cumulative anticholinergic load risk associated with drugs prescribed to elderly cancer patients. Also, to identify the predictors that might lead to raised anticholinergic burden in these patients.MethodologyThis retrospective cross-sectional study included elderly patients (age ≥ 65) diagnosed with cancer and admitted to the adult oncology unit at King Abdullah University Hospital (KAUH) in Jordan during the period between (January 1st, 2019, and January 1st, 2022). The medication charts of 420 patients were evaluated for study outcomes.ResultsOf the total subjects, females represented 49.3%, and the average age was 72.95 (SD = 7.33). A total of 354 (84.3%) patients were prescribed at least one drug carrying anticholinergic burden properties. Median for anticholinergic medications was 3 (IQR = 4). Our study found that 194 (46.2%) patients were at a high risk of adverse events associated with anticholinergic load (cumulative score ≥ 3). Metoclopramide, furosemide, and tramadol were the most frequently prescribed drugs with anticholinergic properties. Alimentary tract drugs with anticholinergic action were the most commonly encountered items in our study population.ConclusionOur study revealed a significantly high prevalence of anticholinergic prescribing among elderly cancer patients. Nearly half of the patients were at high risk of developing serious effects related to anticholinergic activity from the drugs administered. Polypharmacy was strongly associated with increased anticholinergic burden score. Evidence-based recommendations utilizing prescribing strategies for safer alternatives and deprescribing of inappropriate medications could reduce such inappropriate prescribing.     

Toxicity of complementary therapies: an eastern perspective

Chinese traditional medicine is used extensively in Chinese populations, and other Asian countries employ similar therapies. Herbal treatments have a major role in these systems, and although most have a well-established safety record, occasional adverse effects are seen. Problems arise when toxic herbs are used in excessive doses, with improper preparation, or when they are substituted erroneously. There may also be adulteration with Western drugs or heavy metals, and interactions between herbs and Western drugs may also occur. It is always prudent to obtain a complete history of the use of herbal medications during any clinical assessment, particularly in Asian patients.