Anticholinergic Drugs: What They Are, Why They Matter, and Which Ones to Watch

When you take a drug that blocks anticholinergic, a class of medications that inhibit the neurotransmitter acetylcholine in the nervous system. Also known as cholinesterase inhibitors, these drugs are used for everything from allergies to overactive bladder—but they come with hidden risks, especially for older adults. Acetylcholine helps your brain focus, your muscles move, and your organs function properly. When anticholinergic drugs interfere with it, side effects like brain fog, constipation, dry eyes, and trouble urinating aren’t just annoying—they can be dangerous.

One of the biggest concerns is medication-induced delirium, a sudden, reversible state of confusion often triggered by anticholinergic drugs in seniors. It’s not rare. Studies show up to 30% of delirium cases in hospitals are tied to these meds. Common culprits include doxylamine, an antihistamine found in sleep aids like Unisom, and hydroxyzine, used for anxiety and itching but also known for its strong anticholinergic effects. Even Benadryl, which many people think is harmless, falls into this category. These drugs don’t just cause drowsiness—they can shut down mental clarity, increase fall risk, and even accelerate cognitive decline over time.

What makes this worse is that many of these drugs are sold over the counter. People don’t realize they’re taking anticholinergics until they or a loved one starts forgetting names, mixing up words, or acting confused. It’s not Alzheimer’s—it’s a drug reaction. And the good news? Stopping the drug often reverses the symptoms. But you have to know what you’re taking. The posts below break down exactly which medications carry these risks, how to spot the signs in older adults, and what safer alternatives exist. You’ll find real-world examples, from sleep aids to IBS treatments, so you can make smarter choices without guessing.