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Why should anticholinergics be avoided in the elderly?

4 min read

Over one-third of delirium cases in older adults are caused by medication, with anticholinergics being a major culprit. This highlights a crucial question in senior healthcare: Why should anticholinergics be avoided in the elderly? This article explains the heightened risks these common medications pose for older adults.

Quick Summary

Older adults should generally avoid anticholinergics due to increased sensitivity to their adverse effects, including a heightened risk of cognitive decline, falls, confusion, and other serious side effects from the cumulative “anticholinergic burden”.

Key Points

  • Heightened Risk: Older adults are more sensitive to the adverse effects of anticholinergics due to age-related changes in metabolism and decreased acetylcholine production.

  • Cognitive Impairment: Long-term use of anticholinergics is linked to an increased risk of cognitive decline, dementia, and delirium.

  • Fall Risk: Sedation, confusion, and blurred vision from these drugs significantly increase the likelihood of dangerous falls in the elderly.

  • Cumulative Burden: The total anticholinergic burden from multiple medications, including many common OTC drugs, is a major concern.

  • Safer Alternatives: For many conditions like allergies, incontinence, and depression, effective alternatives exist with less severe anticholinergic effects.

  • Do Not Stop Abruptly: Never discontinue an anticholinergic medication without medical supervision, as it can cause withdrawal symptoms.

In This Article

Understanding Anticholinergics and the Aging Body

Anticholinergic medications are a class of drugs that block the action of a neurotransmitter called acetylcholine. Acetylcholine plays a crucial role in many bodily functions, including muscle movement, learning, memory, and regulating the nervous system. While these drugs are effective for treating various conditions, including overactive bladder, allergies, and depression, their impact changes with age.

As people get older, their bodies undergo physiological changes that make them more sensitive to medication side effects. These include a reduced ability of the liver and kidneys to clear drugs from the system, resulting in higher drug concentrations in the blood for longer periods. This, combined with natural age-related decline in acetylcholine production, creates a “double whammy” effect that makes anticholinergics especially problematic for the elderly.

Heightened Risks of Anticholinergic Use in Seniors

The risks associated with anticholinergic use in older adults are numerous and significant. The American Geriatrics Society (AGS) has addressed these risks in its Beers Criteria, a list of potentially inappropriate medications for older adults. These risks are cumulative, meaning that taking multiple anticholinergic drugs, or a single one over a long period, increases the danger.

Cognitive Decline and Dementia Risk

One of the most serious risks is the potential for cognitive impairment and an increased risk of dementia. A 2015 study published in JAMA Internal Medicine revealed a strong link between long-term, high-dose anticholinergic use and an increased risk of developing dementia and Alzheimer’s disease in older adults. This risk is dose-dependent, meaning the higher the cumulative dose over time, the greater the risk. While this study doesn't prove causation, the association is concerning and underscores the need for caution. The confusion and memory impairment caused by these drugs can often be mistaken for normal signs of aging, leading to misdiagnosis or delayed investigation.

Increased Risk of Falls

Anticholinergics can cause central nervous system side effects like dizziness, sedation, and blurred vision, which significantly increase the risk of falls. For an older adult, a fall can have devastating consequences, including fractures, head injuries, and a decline in overall health and independence. The AGS Beers Criteria specifically highlights the increased fall risk as a major reason to avoid these medications in the geriatric population.

Acute Central Nervous System Effects

In addition to long-term cognitive risks, older adults are more susceptible to acute central nervous system (CNS) side effects. These can include:

  • Delirium and confusion: This is a state of severe confusion and disorientation that can be triggered by anticholinergics and is particularly common in hospital settings.
  • Excessive sedation: Many over-the-counter anticholinergics, like certain sleep aids and allergy medicines, cause significant drowsiness that can impair daily activities and increase accident risk.

Common Peripheral Side Effects

Anticholinergics also cause a range of peripheral side effects due to their action outside the brain. These include:

  • Dry mouth
  • Blurred vision
  • Constipation
  • Urinary retention
  • Reduced sweating

These seemingly minor issues can cause major problems for seniors. For example, dry mouth can lead to dental issues, while urinary retention can increase the risk of urinary tract infections.

Assessing the Anticholinergic Burden

The concept of anticholinergic burden (ACB) refers to the cumulative effect of taking multiple drugs with anticholinergic properties. Many drugs not typically classified as anticholinergics have some degree of anticholinergic activity, such as certain antidepressants and antipsychotics. Healthcare providers can use tools like the Anticholinergic Cognitive Burden (ACB) Scale or the Anticholinergic Risk Scale (ARS) to evaluate a patient's total exposure. A higher score on these scales correlates with an increased risk of adverse effects.

Alternatives to Anticholinergic Medications

For many conditions, safer and equally effective alternatives exist. Healthcare providers should review a patient's medication list regularly and consider these alternatives, a process known as "deprescribing".

A Comparison of Anticholinergic vs. Alternative Treatments

Condition Anticholinergic Medication Safer Alternatives for Seniors
Allergies/Insomnia Diphenhydramine (Benadryl, Tylenol PM) Second-generation antihistamines (Cetirizine, Loratadine), Melatonin, Sleep hygiene practices
Overactive Bladder Oxybutynin (Ditropan) Pelvic floor exercises (Kegel exercises), Bladder training, Avoiding bladder irritants like caffeine
Depression Tricyclic Antidepressants (Amitriptyline) Selective Serotonin Reuptake Inhibitors (SSRIs) like Sertraline, Bupropion, Cognitive Behavioral Therapy
Parkinson's Disease Benztropine (Cogentin) Levodopa/Carbidopa

The Importance of Professional Guidance

It is critical that older adults and their caregivers do not abruptly stop taking any prescribed medication without consulting a healthcare professional. Suddenly discontinuing some anticholinergics can cause a rebound effect, known as cholinergic discontinuation syndrome, with symptoms like nausea, sweating, and anxiety. A gradual tapering schedule, overseen by a doctor, is often required.

Conclusion: Prioritizing Patient Safety in Medication Management

The aging body processes medication differently, and the cumulative effect of anticholinergics can pose a significant and often underestimated risk. From increased cognitive decline and falls to less obvious but debilitating peripheral side effects, the evidence points toward careful and limited use of these drugs in the elderly. Prioritizing safer, alternative treatments and non-pharmacological interventions is a cornerstone of responsible geriatric care. Regular medication reviews with a healthcare provider are essential for minimizing anticholinergic burden and ensuring the well-being of older adults. You can read more about medication safety for older adults on the Health in Aging website.

Frequently Asked Questions

An anticholinergic drug is a medication that blocks the action of acetylcholine, a neurotransmitter in the body. This affects nerve impulses in the central and peripheral nervous systems, which can impact bodily functions like memory, muscle contraction, and glandular secretions.

Many common over-the-counter and prescription drugs have anticholinergic effects, including certain antihistamines (like Benadryl), tricyclic antidepressants, some antipsychotics, and medications for an overactive bladder (like oxybutynin).

Older adults are more vulnerable because their bodies clear medications less efficiently, and they have naturally lower levels of acetylcholine. This means anticholinergics have a stronger and longer-lasting effect, amplifying side effects.

While studies have found an association between long-term, high-dose anticholinergic use and an increased risk of dementia, it doesn't definitively prove causation. However, the link is significant enough to warrant caution, and these drugs can certainly cause temporary cognitive issues.

The anticholinergic burden is the cumulative effect of a person taking one or more medications with anticholinergic activity. Taking multiple drugs, even those with mild anticholinergic effects, can build up and lead to significant side effects.

Early signs can include excessive drowsiness, confusion, dry mouth, blurred vision, constipation, or difficulty urinating. These symptoms should prompt a review of all medications with a healthcare provider.

Talk to their healthcare provider. They should review all current medications, including OTC drugs, to assess the anticholinergic burden and discuss potential risks and safer alternatives.

References

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Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.