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Anticholinergic Drugs to Avoid in the Elderly

Medically reviewed by Leigh Ann Anderson, PharmD Last updated on Jun 27, 2019.

Overview | Side Effects | Risk of Dementia | The Beers Criteria | Drugs to Avoid 

What are anticholinergic drugs?

Drugs with anticholinergic properties can be problematic, especially for the elderly. Anticholinergic drugs block (antagonize) the action of the neurotransmitter acetylcholine. A neurotransmitter is a chemical released by nerve cells to send signals to other cells. Acetylcholine is involved in transmitting messages that affect muscle contractions in the body and learning and memory in the brain. Drugs with anticholinergic properties have been used in medicine for many decades in the treatment of such diverse conditions as: 

Side Effects

Why should many anticholinergic drugs be avoided in the elderly? Chemical properties of these drugs can cause a wide array of more pronounced reactions in the elderly.

The central nervous system is very sensitive to anticholinergic side effects due to the substantial decrease in cholinergic neurons or receptors in the brain of older individuals. In addition, the lower ability of the liver and kidney to break down and excrete medications, and the increase in the blood–brain barrier permeability which allows drugs to cross more easily into the brain, are major factors contributing to anticholinergic side effects in older adults.

Most commonly, anticholinergics can cause the following side effects, which may be more pronounced in the elderly:

  • drowsiness or sedation
  • blurred vision
  • dizziness
  • urinary retention
  • confusion or delirium
  • hallucinations
  • increased heart rate
  • dry mouth
  • constipation
  • reduced sweating and elevated body temperature
  • falls and risk for fracture

Anticholinergic drugs fall into many different classes of drugs, so it’s hard for patients to identify or remember these specific drugs. For example, some antihistamines, antidepressants, or even muscle relaxants have anticholinergic properties. Patients with delirium, dementia, constipation, and benign prostatic hypertrophy (BPH) are particularly at risk of anticholinergic adverse drug events. Refer to the list below for a suggested list of anticholinergic drugs to avoid in older patients.

Dementia Risk

Anticholinergic drugs should be avoided in patients with dementia, cognitive impairment, or delirium. A study published in JAMA Internal Medicine noted that higher cumulative anticholinergic medication use was associated with an increased risk for dementia.

Data in this study were evaluated from a prospective, population-based cohort study using data from the Adult Changes in Thought Study. Over 3,400 participants aged 65 and older with no dementia were enrolled at study entry between 1994 and 2003.

It was found the most common anticholinergic drug classes used by the elderly in the study were:

Overall, a higher cumulative use of anticholinergic medications (3 years or more) across all subclasses was linked with a 54% higher risk for developing dementia than taking the same dose for three months or less. Results also suggested that the risk for dementia with anticholinergics remain even after drug discontinuation.

A case-control study published in 2019 in JAMA Internal Medicine also highlighted risk of dementia with long-term use of anticholinergics in persons 55 years or older.

  • The population consisted of 58,769 patients with a diagnosis of dementia and 225,574 control patients.
  • Utilizing prescription information for 56 drugs with strong anticholinergic properties, researchers analyzed total anticholinergic exposure by using the total standardized daily doses (TSDDs) of anticholinergic drugs prescribed during the 11 years prior to the diagnosis of dementia.
  • Associations with dementia were significant for the anticholinergic antidepressants, antiparkinson agents, bladder antimuscarinics, and certain seizure medications. Lists of specific anticholinergic agents included as exposures can be viewed here.

Anticholinergic drugs should not be used in conditions such as:

In the acute hospital setting, anticholinergic drugs should not be started in the elderly unless clearly needed. Also, use of any anticholinergic drug given as an outpatient should be suspended, unless clearly needed with no other more appropriate alternatives.

In addition, taking opioids for pain and anticholinergics together should especially be avoided due to a greater risk of confusion, sedation, hallucination, problematic constipation or fecal impaction.

Patients and clinicians should avoid abruptly stopping long-term anticholinergic drugs, when possible, to minimize withdrawal symptoms. A slower taper may help to avoid side effects.

The Beers Criteria

Per the 2019 Beers Criteria, it is well established that many drugs with anticholinergic properties should be avoided in the elderly whenever possible. In addition, drug Interactions with anticholinergics are common and pharmacists and physicians should screen for these drug interactions in patients who must use a drug with anticholinergic properties. It is also important to screen for and avoid combined use of two or more drugs that both have anticholinergic effects to minimize the risk for adverse drug effects. Changes to anticholinergic agents were not denoted in the 2019 update to the Beers Criteria.

List of Anticholinergic Drugs to Be Avoided in the Elderly

Note: Many of the below drugs are found in over-the-counter (OTC) products or in combination with other medications (prescription or OTC), so always check with your pharmacist if you are concerned about the use of anticholinergic drugs. For example, multiple over-the-counter sleep medications contain diphenhydramine (Benadryl), a strong anticholinergic antihistamine. This is not a complete list of anticholinergic medications, but includes many of the most common ones to avoid, when possible.

Antihistamines, First-Generation

* Use of diphenhydramine in acute allergic reactions may be appropriate; many OTC sleep agents have diphenhydramine as an active ingredient, be sure to check labels.

Antiparkinsonian Agents*

* In general, these agents are not recommended for prevention of extrapyramidal symptoms with antipsychotics. In addition, more-effective agents are available for treatment of Parkinson disease, especially for older individuals.

Skeletal Muscle Relaxants

Antiarrhythmics

Antidepressants

Antimuscarinics (Urinary Incontinence)

Antipsychotics*

*Boxed warnings exist about the use of antipsychotics in the elderly with dementia. Antipsychotics are not approved for use in psychotic conditions related to dementia. Antipsychotics may increase the risk of death in older adults with dementia-related conditions.

Antispasmodics

Antiemetics

See Also:

Sources

  1. American Geriatrics Society 2019 Updated AGS Beers Criteria for Potentially Inappropriate Medication Use in Older Adults.  American Geriatrics Society Beers Criteria Update Expert Panel. J Am Geriatr Soc.;00:1– 21, 2019.
  2. Salahudeen MS, Duffull SB, Nishtala PS. Anticholinergic burden quantified by anticholinergic risk scales and adverse outcomes in older people: a systematic review. BMC Geriatr. 2015;15:31. Published 2015 Mar 25. doi:10.1186/s12877-015-0029-9. Accessed June 17, 2019 at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4377853/
  3. American Geriatrics Society 2015 Updated Beers Criteria for Potentially Inappropriate Medication Use in Older Adults. J Am Geriatr Soc 63:2227–2246, 2015. Accessed December 12, 2018 at https://onlinelibrary.wiley.com/doi/full/10.1111/jgs.13702
  4. Campbell N, Boustani M, Limbil T, et al. The Cognitive Impacts of Anticholinergics: A Clinical Review. Clin Interv Aging. 2009;4: 225–233.
  5. Gray SL, Anderson ML, Dublin S et al. Cumulative use of strong anticholinergics and incident dementia: A prospective cohort study. JAMA Intern Med 2015;175:401–407. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4358759/
  6. Merz B. Common anticholinergic drugs like Benadryl linked to increased dementia risk. Harvard Health Blog. September 10, 2015. Accessed June 16, 2019 at https://www.health.harvard.edu/blog/common-anticholinergic-drugs-like-benadryl-linked-increased-dementia-risk-201501287667
  7. Coupland CA, et al. Hill T, Dening T. Anticholinergic Drug Exposure and the Risk of Dementia. A Nested Case-Control Study. JAMA Intern Med. Published online June 24, 2019. doi:10.1001/jamainternmed.2019.0677. Accessed June 26, 2019 at https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2736353
  8. Coupland CAC, Hill T, Dening T, Morriss R, Moore M, Hippisley-Cox J. Anticholinergenic drug exposure and the risk of dementia: a nested case-control study. JAMA Intern Med. Published online June 24, 2019. doi:10.1001/ jamainternalmed.2019.0677. Accessed June 27, 2019.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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