Ask the Pharmacist

Q) I saw on the news the other day that there are a number of over the counter medications that can cause dementia. Is this true and if so, which drugs are we talking about?

A) There have been scattered reports in the media linking the use of relatively large number of drugs to the potential for one to be diagnosed later in life with dementia.

The drugs fall into a variety of classes that treat conditions ranging from depression to urinary frequency. However, the one trait that all of these drugs share is that they have anticholinergic properties. A drug is described as having this property when it displays an ability to block the action of the neurotransmitter acetylcholine at its target sites.

Acetylcholine, at its essence, is involved in the sending of signals to other cells throughout the nervous system. Its roles include such diverse tasks as muscle contraction, activating pain responses, regulating REM sleep function and playing a role in memory and learning.

Drugs that impact the function or amount of this neurotransmitter have the ability to greatly improve a number of medical disorders. Conversely, their use tends to be limited by their propensity to cause side effects in many of the patients who take them.

In this most recent study conducted in the United States, 3,500 men and women over the age of 65 agreed to let researchers look at their drug profiles (both for prescription and over the counter drugs) for the previous 10 years. When researchers looked at the data, they found that people who had used anticholinergic drugs were more likely to have been diagnosed with dementia than those who had not. What’s more, dementia risk seemed to increase in sync with the cumulative dose of anticholinergics taken. And, perhaps most incriminatingly, it was found that those who took these drugs for 3 years or more had a 54% increased risk relative to those taking the same dose for 3 months or less. These findings did not completely come out of the blue.

Drugs with properties like this have been on the well-known Beers List of medicines that have been deemed potentially inappropriate for seniors to take. Their inclusion on this list was based upon their long list of adverse effects such as drowsiness, confusion, urinary retention, dry mouth, dry eyes, short term memory impairment, constipation and links to increases in falling and/ or being hospitalized.

While anybody can suffer from these side effects in taking an anticholinergic (but, of course, not everybody does), seniors seem to be far more susceptible. This is because our bodies naturally produce less acetylcholine as we age and hence, when a drug blocks its actions, seniors get hit with a so-called “double-whammy”. As well, the ageing process reduces our ability to break down and eliminate drugs while also simultaneously decreasing our body mass. These two factors also make cholinergic drugs more problematic in the elderly.

Now, to put somewhat of a damper on all of this negativity, this study does not prove these drugs cause dementia (just that there seems to be an association) and many seniors take these drugs, benefit from them, and do not seem to struggle with their potential side effects.

What doctors are suggesting is to review all of the medications you take, both from the doctor and those you buy on your own, and have them graded for what is called an overall “cholinergic burden”.

Drugs that affect acetylcholine levels do so to varying degrees and are assigned a number reflecting that. The scale is printed all over the internet and is very straightforward. A zero indicates the drug has no impact on acetylcholine. A ‘1’ indicates only a slight lowering whereas a ‘2’ or ‘3’ indicates a medium or high impairment of acetylcholine levels.

For those concerned with these findings, or who believe the way they currently “feel” might be due to this lack of acetylcholine, there are steps they can take. The key is to identify which drugs they take that are 2 or 3’s (if any) and either take them off the medication or change them to an alternative that has less impact.

Just what types of drugs are we talking about? Well the list is too long to include here but well known examples (and in brackets drugs that could be used alternatively with less effects on acetylcholine) include the antihistamines Benadryl/ diphenhydramine and perhaps Reactine/ cetirizine (try Claritin or Aerius instead), the anti-nausea drugs Gravol/ dimenhydrinate or chlorpromazine (try ginger, domperidone or ondansetron instead), the antacid Zantac/ ranitidine (try Pepcid/ famotidine), the anti-diarrheals Imodium/ loperamide or Lomotil (try Kaopectate, Pepto-Bismol or cholestyramine), the pain killer tramadol (just about any other pain killer not called Demerol will have less effects), the tricyclic antidepressants such as amitriptyline (just about any of the newer antidepressants (e.g. Effexor) other than Paxil/ paroxetine which is problematic), almost all of the prescription and over the counter muscle relaxants (sorry, I don’t have a great alternative for these.

Diazepam has some muscle relaxant properties but comes with significant issues not related to acetylcholine) and literally a host of other drugs. However, one class that should get signaled out due to the frequency that they are prescribed are the drugs used to treat an overactive bladder (the term used to describe people who urinate both frequently and with great urgency). These drugs are used mainly in seniors and usually on a daily and long-term basis.

All of the main treatment options (save two) are part of a class of drugs that are called the anticholinergics. This class includes commonly prescribed drugs such as Ditropan/ oxybutynin, Vesicare/ solifenacin, Detrol/ tolterodine and a number of others. The two medical options that can help for overactive bladder but that do not affect acetylcholine levels are botox injections and the prescription drug mirabegron/ Myrbetriq.

The point with all of this is that while drastic action today is not necessary, if you are concerned about these possible findings or feel that some of the symptoms we have discussed apply to you, make an appointment with your pharmacist to assess the “cholinergic burden” your drugs may be inflicting upon you.