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Commonly Prescribed Anticholinergic Drugs Linked to Dementia

A very large study from the UK has reinforced a link between anticholinergic drugs are dementia. Which drugs are most problematic? Might you be taking anticholinergic drugs without realizing it?

Alzheimer’s disease is scary. It robs people of their memories and their ability to function. Many people think it’s brought on by bad genes or bad luck. But there is mounting evidence that our environment also plays a key role in the development of dementia. Over the last decade there is growing recognition that a class of medications known as anticholinergic drugs could be contributing to cognitive decline or even dementia. A new study from the UK reinforces this concern (BMJ April 25, 2018).

Anticholinergic Drugs Block a Key Brain Chemical:

Acetylcholine (pronounced ASS-se-TEEL-kol-EEN) is a neurotransmitter that plays a critical role in brain function. People with Alzheimer disease make less of this important brain chemical. Doctors suspect that medications that interfere with the function of acetylcholine, known as anticholinergic drugs, may cause cognitive impairment.

Learn about the history of anticholinergic drugs, brain fog and “twilight sleep” at this link:

New Research Adds Fuel to the Fire:

Now a large study of people in the United Kingdom has confirmed that some types of anticholinergic drugs can lead to dementia after a few decades. Researchers examined health records from primary care practices throughout the UK.

More than 40,000 people between 65 and 99 were diagnosed with dementia at some point between April 2006 and July 2015. They were matched to 284,000 control subjects of comparable age and sex, but without dementia. This is one of the largest anticholinergic drug studies to date. Over 27 million prescriptions were analyzed over the course of the research.

Investigators reviewed prescriptions for drugs with anticholinergic activity. They found that people taking an anticholinergic medicines were 10 percent more likely to develop dementia in the ensuing years.

In absolute terms, a 65 year-old-person has about twelve chances in one hundred of developing dementia by age 80 if she takes an anticholinergic prescription. The researchers found a dose-response effect, with more anticholinergic medicines linked to a higher chance of a dementia diagnosis.

Which Anticholinergic Drugs Were Worrisome?

Many of the people who developed dementia had taken drugs to treat depression, Parkinson’s disease or overactive bladder. The scientists conclude that there is:

“a robust association between some classes of anticholinergic drugs and future dementia incidence.”

Antidepressants: A Clear Association

Two specific antidepressant drugs stood out in the UK Study. Amitriptyline (Elavil) and paroxetine (Paxil) have substantial anticholinergic activity. The use of strong anticholinergic antidepressants was associated with a 30% increased risk of dementia in future years.

According to our calculations, roughly 10 million amitriptyline prescriptions have been dispensed each year over the last decade. Paroxetine averages around 15 million prescriptions per year. Millions of people take such drugs every day.

Amitriptyline is often prescribed for things other than depression. Many people take it for neuropathy or nerve pain, migraine headaches, fibromyalgia and insomnia. Paroxetine is prescribed for depression, OCD, panic, social anxiety disorder, PTSD, premenstrual dysphoric disorder and the hot flashes of menopause.

Stopping either of these drugs suddenly can produce what is called discontinuation syndrome. That’s a sanitized description of very unpleasant withdrawal symptoms. They can include dizziness, diarrhea, nausea, brain fog, brain zaps, irritability, anxiety, insomnia, sweating and fatigue. Such reactions upon stopping these anticholinergic drugs makes it hard to quit.

No one should ever stop an antidepressant suddenly. This process should always be under medical supervision. Gradual tapering may take months to accomplish if it is decided that the concerns of dementia are worrisome enough to discontinue such drugs.

Antidepressant Withdrawal Feels Like Circles of Hell

Overactive Bladder Drugs:

Two other anticholinergic drugs were found to be associated with the development of dementia over time. They were oxybutynin (Ditropan) and tolterodine (Detrol). The authors concluded that both the antidepressants mentioned above and overactive bladder drugs were:

“consistently associated with incident dementia. These relations were seen even for exposures 15-20 years before the diagnosis of dementia, suggesting that reverse causation or confounding with early dementia symptoms are less likely explanations for the effect.”

Anticholinergic Drugs and Dementia | The Editorial

Health professionals commenting on the new UK study are quick to caution patients not to stop any medications that might have anticholinergic activity. We agree that this research requires thoughtful communication between patients and prescribers. But an editorial in the same issue of the BMJ (April, 25, 2018) asks the question: “Should we be concerned?”

The authors point out that anticholinergic drugs are taken by 10-27% of older adults.

“It is well established that these drugs can cause temporary short term impairment in cognition, including attention and reaction time. Over the past decade, however, mounting evidence suggests that overall use of anticholinergics might be associated with an increased risk of dementia.”

They conclude their editorial with this recommendation:

“In the meantime, what should clinicians do until studies are conducted to further elucidate the underlying biological mechanisms and determine the risk of dementia with specific classes, including over-the-counter anticholinergic antihistamine use not captured by this or previous studies? As suggested by guidelines, anticholinergics in general should be avoided in older adults. Specifically, for most highly anticholinergic drugs, non-pharmacological and pharmacological alternatives are available and should be considered.”

People’s Pharmacy Perspective:

There will be situations when anticholinergic drugs may not be avoided. In such situations it is important for the patient, the family and the physician to weigh the benefits and the risks of a large anticholineric drug burden on the long-term health of the patient.

To help with that conversation we include a link to a list of anticholinergic drugs:

Share your own thoughts on anticholinergic drugs in the comment section below.

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About the Author
Joe Graedon is a pharmacologist who has dedicated his career to making drug information understandable to consumers. His best-selling book, The People’s Pharmacy, was published in 1976 and led to a syndicated newspaper column, syndicated public radio show and web site. In 2006, Long Island University awarded him an honorary doctorate as “one of the country's leading drug experts for the consumer.”.
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