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7 Common Drugs That Are Toxic for Your Brain

These widely used medications can be especially harmful for older adults

By Leslie Kernisan, MD for Next Avenue

Want to keep your brain — or the brain of someone you love — as healthy as possible?

Of course you do. So you've been learning about what to do: what kind of physical exercise to try, what kind of brain games to play, what kinds of foods to eat, what kinds of supplements to take, what kind of sleep to get.

But you should also be learning what not to do.

Specifically, you should learn what kinds of toxins to avoid to protect your brain's health. And even if you are super-fit and never take any medications, it's good to know what to help your friends and family avoid.

As a doctor specialized in aging, I have noticed that even health-conscious people rarely know that many commonly used medications are bad for brain health.

And I'm not just talking about habit-forming sedatives. Drugs like Valium do indeed harm the brain, but they're much less often used than another class of brain-toxic drugs: the "anticholinergic" drugs.

Warning Label Needed?

These drugs are in everything from allergy medicines to muscle relaxants to painkillers. They are in many over-the-counter (OTC) medications, and they are often prescribed for a variety of common health complaints.

I've never quite understood why there isn't more of a brain health warning on these drugs. They block acetylcholine, a key neurotransmitter in the body. This leads to lower brain function, which people often experience as sedation.

Sometimes, that drowsiness is why people take the drugs, and a little sedation might sound benign. But if your brain is older, or otherwise vulnerable, don't underestimate these drugs. Research has linked them to increased risk of Alzheimer's disease and also to hospitalizations in older adults. And the American Geriatrics Society has cautioned older adults about them for years.

The drugs literally have the opposite effect of medications often used to treat Alzheimer's. Donepezil (brand name Aricept), for example, increases the neurotransmitter acetylcholine by blocking the brain enzyme that breaks it down.

So for better brain health, it's definitely worth learning to spot these drugs and avoid them. Here are seven common types of anticholinergic drugs:

1. Sedating antihistamines. The prime example is diphenhydramine (brand name Benadryl), which is available over-the-counter and has strong anticholinergic activity. Non-sedating antihistamines, such as loratadine (brand name Claritin) are less anticholinergic and are safer for the brain.

2. PM versions of over-the-counter (OTC) painkillers. Most OTC painkillers, such as acetaminophen and ibuprofen (brand names Tylenol and Motrin, respectively) come in a "PM" or night-time formulation, which means a mild sedative — usually an antihistamine — has been mixed in. Ditto for night-time cold and cough medications such as Nyquil.

3. Medications for over-active bladder. These include bladder relaxants such as oxybutynin and tolterodine (brand names Ditropan and Detrol, respectively).

4. Medications for vertigo or motion sickness. Meclizine (brand name Antivert) is often prescribed to treat benign positional vertigo. It's also used to treat motion sickness.

5. Medications for itching. These include the strong antihistamines hydroxyzine (brand name Vistaril) and diphenhydramine (brand name Benadryl), which are often prescribed for itching or hives.

6. Medications for nerve pain. An older class of antidepressant known as "tricyclics" isn't used for depression that much any longer, but it's still used to treat pain from neuropathy. (These are also prescribed to reduce the chance of chronic nerve pain after shingles.) Commonly-used tricyclics include amitriptyline and nortriptyline.

7. Muscle relaxants. These include drugs such as cyclobenzaprine (brand name Flexeril) and they are often prescribed for back or neck pain.

Many more medications have strong anticholinergic effects, but they tend to be prescribed less often. Ask your doctor or pharmacist if you want help spotting all anticholinergics you might be taking.

Who Should Avoid Anticholinergics

You should especially avoid or minimize anticholinergics if you:

• Are worried about your memory
• Have been diagnosed with mild cognitive impairment or dementia such as Alzheimer's disease
• Want to reduce your risk of developing Alzheimer's

If you're younger and have a healthier brain, in the short-term, anticholinergics might just make you drowsy and maybe a little unsteady on your feet.

But research suggests that anticholinergics are basically a low-level toxin for the brain and cumulative exposure can add up to definite harm. So avoiding them — and other brain-toxic drugs — is a sensible part of promoting brain health.

Remember, when it comes to brain health, it's not just what you do; it's also what you don't do. So after eating your brain-healthy breakfast, take a good look in your medicine cabinet — or your parents' cabinet. Spot those brain toxins. Your brain health is worth it.

Copyright© 2014 Next Avenue, a division of Twin Cities Public Television, Inc.