Anticholinergic Drugs: What They Are, How They Work, and What to Watch For

When you take an anticholinergic drug, a medication that blocks the neurotransmitter acetylcholine to reduce muscle spasms, secretions, or nerve signals. Also known as cholinergic blockers, these drugs are used for everything from overactive bladder to motion sickness and even some types of depression. But they don’t just stop unwanted symptoms—they can slow down your brain, dry out your mouth, and make you dizzy or confused, especially as you get older.

These drugs work by interrupting the cholinergic system, the network of nerves that uses acetylcholine to control muscle movement, heart rate, digestion, and memory. When this system is blocked, your body can’t signal properly—so sweat stops, your eyes get dry, your bladder relaxes, and your stomach slows down. That’s why they help with drooling in Parkinson’s or cramps in IBS. But that same blockage can also make you forget where you put your keys or cause you to stumble because your balance is off. The longer you take them, the higher your risk of cognitive decline. Studies show people on multiple anticholinergics for years have up to a 50% higher chance of developing dementia.

Many common meds you might not even think of as anticholinergic fall into this category. Think Benadryl for allergies, some sleep aids, certain antidepressants like amitriptyline, and even some stomach meds like hyoscyamine. It’s not just one pill—it’s the anticholinergic burden, the total effect of all anticholinergic drugs you’re taking together. A single low-dose anticholinergic might be fine. But if you’re on three or four, even weak ones, the effects add up. Older adults are especially vulnerable because their bodies clear these drugs slower, and their brains are more sensitive to the blockage.

These drugs also play a role in other health issues you might not connect to them. For example, they can make asthma worse by drying out airways, or worsen constipation in people with diabetes. They interact dangerously with other sedating meds, like opioids or benzodiazepines, increasing fall risk. And if you’re taking them for an overactive bladder, you might not realize they’re also causing your dry eyes, constipation, or memory lapses. It’s not always obvious.

That’s why knowing what you’re on matters. If you’re on any of these drugs long-term, talk to your doctor about alternatives. There are often newer, safer options—like mirabegron for bladder control instead of oxybutynin, or SSRIs instead of tricyclics for depression. You don’t have to live with side effects just because a pill was prescribed years ago.

Below, you’ll find real-world guides on how these drugs affect your kidneys, interact with other meds, and show up in unexpected places—like in older adults taking multiple prescriptions. You’ll also see how pharmacists help patients spot hidden anticholinergic risks and switch to safer choices. This isn’t just about knowing what’s in your medicine cabinet. It’s about understanding how those pills are quietly changing your body—and what you can do about it.