March 19, 2015

Bad News: Many Anticholinergic Drugs Popular with Seniors Carry Irreversible Dementia Risks

Earlier this week, we discussed the risks that statins -- those cholesterol-lowering drugs -- pose for seniors. Today it's anticholinergics, agents that block the neurotransmitter acetylcholine in the central and peripheral nervous systems. Studies suggest that 37% of people 65+ take these anticholinergic medications.

Drugs that fall into this class include tricyclic antidepressants, antihistamines, meds used to treat overactive bladders, and -- of special concern to me -- over-the-counter (OTC) sleep aids. A new study published in January shows that all these drugs may increase the risk of dementia and Alzheimer's.

The neurotransmitter that these drugs block -- acetylcholine -- helps transmit messages in the nervous system. It's linked to learning and memory, and it also stimulates muscle contractions.

"We have known for some time that even single doses of these [anticholinergic] medications can cause impairment in cognition, slower reaction time, and reduced attention and ability to concentrate," said Shelley Gray, the study's principal author and pharmacy professor at the University of Washington in Seattle.

At first, "the thinking was that these cognitive effects were reversible when you stopped taking the medication," said Gray. But her study found a link between heavier use of these medications and dementia, "a non-reversible, severe form of cognitive impairment."

Gray's team tracked nearly 3,500 men and women 65+ who'd taken part in Adult Changes in Thought (ACT), a long-term study conducted by the University of Washington and Group Health, a Seattle healthcare system. The researchers used Group Health's pharmacy records to determine all the drugs, prescription and OTC, that participants had taken during the previous ten years. On average, their health was monitored for about seven years.

During that time, 800 of the volunteers developed dementia, and about 80% of those individuals had Alzheimer's. Researchers found that people who used anticholinergic drugs were more likely to have developed dementia. Moreover, the risks increased as cumulative doses increased. Study participants who took anticholinergics for the equivalent of three years or more showed dementia risks 54% greater than those who took the these drugs for less time. 

Many drugs have stronger effects on seniors. With age, the kidneys and liver clear drugs from the system more slowly, so drug levels in the blood remain higher longer. People also gain fat and lose muscle mass with age, which changes the way the body processes drugs. In addition, older people tend to take more prescription and OTC medications, each of which could suppress, enhance, or complicate the effectiveness of the others.

The Dangerous Drugs
In 2008, geriatrician Malaz Boustani at the Indiana University School of Medicine developed the anticholinergic burden scale (ACB), which places these drugs into three categories according to the severity of their effects on the mind. It's a good idea to steer clear of drugs in ACB category #3, which indicates the greatest risk. Here are some of those ACB category #3 meds popular with seniors:

Sleep Aids: Virtually all the OTC sleep aids fall into high-risk category #3. Benadryl and the various "PM" pills (e.g., Aleve PM, Tylenol PM) use the active ingredient diphenhydramine, which carries a #3 rating. Each pill contains 25mg of diphenhydramine, and the recommended dosage is two pills (50mg). Other sleep aids -- like Unisom -- use doxepin, another category #3 drug. Those pills contains 25mg each, but the recommended dosage is only one pill. 

Tricyclic Antidepressants: ABC#3 drugs include amitriptylines like Elavil, desipramine (Norpramin), doxepin (Sinequan), imipramine (Tofranil), nortriptyline (Pamelor). and paroxetine (Paxil).

Antihistamines (H-1 Blockers): Drugs rated ABC#3 include chlorpheniramine (Chlor-Trimeton), diphenhydramine (Benadryl), hydroxyzine (Atarax, Vistaril).

Overactive Bladder: The high-risk drugs here include oxybutynin (Ditropan), propantheline (Pro-Banthine), and tolterodine (Detrol).

Antiparkinson Medications: benztropine (Cogentin), trihexyphenidyl (Artane)

My Concerns About the Study
For years, I used and eventually abused Tylenol PM, especially when I added some Ambien to the mix. That misuse led to what I've dubbed the "Summer from Hell," which proved to be the wake-up call I needed.

I haven't used Ambien since then, and I've rarely used Tylenol PM or other traditional sleep aids. I've found that the serotonin booster 5-HTP is effective in warding off insomnia, as well as depression and constipation.

But the new study clearly suggests that my years of using the anticholinergic Tylenol PM may well carry a lasting effect: an increased risk of dementia.


John Schappi said...

Here's a comment I received in the HealthUnlocked ( Parkinson's forum:

Anticholenergics were the only treatment for PD pre L Dopa but they have been well out of favor in most countries for many years. The advice for use usually says to avoid with older patients particularly.

John Schappi said...

Here's a comment I received in the HealthUnlocked ( Parkinson's forum:

Anticholenergics were the only treatment for PD pre L Dopa but they have been well out of favor in most countries for many years. The advice for use usually says to avoid with older patients particularly.

John Schappi said...

Another comment from HealthUnlocked:

One important group of medications that is mentioned in your blog but not in your above post, is "Antiparkinson Medications: benztropine (Cogentin), trihexyphenidyl (Artane)"

My mum was on trihexyphenidyl (branded as benzhexol), for a very long time. She now has dementia, which may or many not have happened without this medication - I know it's impossible to tell. But when she first suffered from hallucinations, around five years ago, the consultant drastically lowered her dose, and the hallucinations disappeared for several years.

They did come back again recently with her general dementia, which seems to follow the Lewy body pattern. Who knows whether the trihexyphenidyl hastened the dementia or even caused it. I suspect she would have had it anyway, since it seems the kind linked to the disease, but maybe without it it would have come later or not been so severe. Like I say, we can't tell for sure, but it's an interesting study

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