Although many anticholinergic drugs are most usually prescribed for severe disease like depression, Parkinson disease and psychiatric disorders, some of them can be bought without prescription, and include many over-the-counter medications commonly used (table 1).
Another important fact to pay attention is the so called “anticholinergic burden” – that is the cumulative effect of taking multiple medicines with anticholinergic properties. Some drugs used in other indications (Table 1) are not classified as anticholinergic drugs because this is not their main action. However, these still have a more or less strong anticholinergic activity. Because each drug has a slightly different effect, it may therefore be more or less likely to cause cognitive decline. The anticholinergic activity of a drug can be ranking, ranging from no anticholinergic activity (=0) to high anticholinergic activity (=3) (see also table 2)
It turns out that the concomitant use of many drugs with low anticholinergic activity can lead to a cumulative anticholinergic effect and consequently to a high anticholinergic burden.
Drugs such as antibiotics, corticosteroids, anti-acids and diuretics can have low anticholinergic effects. Unfortunately, elderly people are usually prescribed many medications at the same time, which is also called polypharmacy. These patients are then significantly more susceptible to anticholinergic burden and its negative side effects, including an increased risk of dementia.
In table 2 you can find a list with the most common used medication and their classification according to anticholinergic activity. It can be used to calculate anticholinergic burden.