Anticholinergic medications function by blocking acetylcholine, a neurotransmitter that carries signals between nerves for involuntary processes like saliva production and bladder control. The term “anticholinergic burden” describes the cumulative negative impact from taking one or more of these drugs. The effects can build up over time, and the overall impact depends on the number of anticholinergics used, their strength, and the duration of use.
Medications Contributing to Anticholinergic Burden
The cumulative effect known as anticholinergic burden often arises from the use of multiple common medications, some of which are available without a prescription. These effects are not limited to a single class of drugs but are present across a wide spectrum of treatments for various conditions.
A significant source of this burden comes from first-generation antihistamines, such as diphenhydramine, which is the active ingredient in many allergy medications and over-the-counter sleep aids. Tricyclic antidepressants, including amitriptyline, are another major category with strong anticholinergic properties prescribed for nerve pain and depression.
Medications used to manage an overactive bladder, like oxybutynin, function specifically by blocking acetylcholine to relax the bladder muscle. Certain muscle relaxants and drugs prescribed for vertigo and motion sickness also possess these anticholinergic effects. Because these medications are prescribed for very different health issues, patients and even healthcare providers may not immediately recognize the overlapping anticholinergic impact of combining them.
Symptoms of a High Anticholinergic Burden
The signs of a high anticholinergic burden can be separated into effects on the body and effects on the brain. These classic side effects include a persistently dry mouth, blurred vision, difficulty urinating or urinary retention, and constipation. Some individuals may also experience a rapid heartbeat as the body’s systems are disrupted.
The impact on the central nervous system includes a range of cognitive symptoms. Individuals may experience drowsiness, dizziness, confusion, and a decline in memory and concentration. In more severe instances, particularly in vulnerable individuals, a high burden can lead to a state of delirium, which is a sudden and serious change in mental status.
Over the long term, a sustained high burden is associated with a greater risk of cognitive decline. Studies have indicated a connection between the long-term use of medications with strong anticholinergic effects and an increased likelihood of developing dementia.
How Anticholinergic Burden Is Measured
To quantify a patient’s risk, healthcare professionals use clinical tools known as anticholinergic risk scales. These scales provide a systematic way to assess the cumulative impact of all the medications an individual is taking.
One of the most frequently used tools is the Anticholinergic Cognitive Burden (ACB) Scale. This scale categorizes medications based on the strength of their anticholinergic effects, assigning points accordingly. For instance, a drug with mild effects might receive a score of 1, while a drug with strong effects would be assigned a 3.
A healthcare provider calculates a patient’s total score by adding up the points from each anticholinergic medication they use. A higher cumulative score signals a greater overall burden and a correspondingly higher risk for experiencing adverse effects, such as falls or cognitive impairment.
Management in High-Risk Individuals
Managing anticholinergic burden is important for high-risk populations, especially older adults. Age-related changes in how the body processes and responds to drugs, combined with the higher likelihood of taking multiple medications (polypharmacy) for various health conditions, place them at increased risk. Pre-existing cognitive vulnerabilities can also be worsened by these medications.
The primary management strategy involves a thorough medication review conducted by a healthcare provider. This review aims to identify all sources of anticholinergic effects, from both prescription and over-the-counter products.
This process often leads to “deprescribing,” which is the planned and supervised tapering or stopping of medications. A clinician may look for safer, alternative treatments or determine that a particular medication is no longer necessary. This reduction of the anticholinergic load can help reverse adverse effects and improve a person’s quality of life. Patients should never attempt to stop or change their medication doses without consulting a medical professional, as sudden discontinuation can cause its own set of problems.