What Are Anticholinergic Effects?

Anticholinergic effects are caused by drugs that block the action of acetylcholine. Acetylcholine is a neurotransmitter—a chemical messenger that helps nerve cells communicate.

Acetylcholine helps with memory, learning, and concentration. It also helps control the functioning of the heart, blood vessels, airways, and organs of the urinary and digestive tracts. So drugs with anticholinergic effects can disrupt the normal functioning of these organs. Anticholinergic effects include confusion, blurred vision, constipation, dry mouth, light-headedness, difficulty starting and continuing to urinate, and loss of bladder control. Most of these effects are undesirable.

Older people are more likely to experience anticholinergic effects because as people age, the body produces less acetylcholine. Also, cells in many parts of the body (such as the digestive tract) have fewer sites where acetylcholine can attach to them. Thus, the acetylcholine produced is less likely to have an effect, and the effect of anticholinergic drugs is greater.