Trouble sleeping? Overactive bladder? Someone recommended a low-dose anti-depressant for chronic pain? These are three common scenarios in which people take one of the drugs classed as anti-cholinergics, a category of that acts directly on the "cholinergic" receptors in our body, occuring in different places, including our central nervous system. Eggs are a "brain food" because they are rich in choline, used to make a neurotransitter called acetyl choline. Actually, we need more choline as we age, not a blockade of our acetyl-choline receptors.
The sleep inducing antihistamines are available over the counter and include Sominex, Unisom, Sleep-eez, and Nytol, mostly relying on diphenhydramine, but also other antihistamines that are also in the same category. As you know, focusing on sleep quality is important for maintaining good health. There are many avenues to try rather than regular use of antihistamines.
The bladder controlling drugs, some OTC and some by prescription, are oxybutynin (Ditropan) and tolterodine (Detrol). Bladder control is more challenging than the other two categories but hypnosis, bio-feedback, and habit change can reduce the need for regular intake of these medications.
The prescription requiring anti-depressants used for pain are in the tricyclic category, such as doxepin (Sinequan or Rozerem) or amitryptyline (Elavil). They are recommended for neuropathic pain (often ameliorated by normalizing vitamin B levels, a better fix!) and also for migraine prevention. Pain syndromes usually require a comprehensive evaluation of genetics, nutritional adequacy, anti-oxidant capacity and levels of inflammation to design a physiological approach rather than a pharmaceutical one.
A new study, published online in JAMA Internal Medicine on January 26, provies the strongest evidence yet that you're risking brain function by taking these drugs with any regularity. The study followed over 3,400 people, 65 and older, from 1994-2012. The measure of drug consumption was derived from pharmacy dispensing data, yielding total standardized daiy doses over 10 years.
Comparing those who developed dementia with cognitively intact people, there was an increased hazard ratio (more likely to have dementia) if your cumulative days of using the medication was 91 days over a 10 year period. (People using the medication less than 91 days seemed to be untroubled by that degree of use.) At the highest end, those who took the medications more than 1095 times over 10 years (approximately 100 times a year, or every third day) had a marked increase in rate of dementia, a hazard ratio of 1.54, or 50% more likely than non-drug users to develop dementia.
So yes - if you want to take these drugs very occasionally for whatever relief they provide, that is a sensible decision. Taking them with regularity (two to three times a week) puts you at markedly increased risk for... well, for no longer being able to make a sensible decision.