benadryl cause dementia

Benadryl shrinks your brain. And so do these other common drugs.

Recent scientific findings show that Benadryl may cause dementia and its use is strongly linked to cognitive decline and shrinking of the brain.  Say what? Yep.  A study published in the JAMA in January 2015 provided one of the first demonstrations of this link, but a more recent study out of the University of Indiana confirms the connection between brain atrophy and anti-cholinergic drugs.

Other over-the-counter anti-cholinergic drugs linked to cognitive decline include the sleep aids Unisom and Tylenol PM, the cough medicine Dimetapp and the motion sickness medicine Dramamine.  Two commonly prescribed drugs for over-active bladder, oxybutynin and tolterodine, are also closely linked to brain decline, as are the tricyclic anti-depressants and migraine medications doxepin and amitryptiline. Same thing with Paxil, commonly prescribed for depression.

Aren’t you just being dramatic? What did the study REALLY say?

The study used brain imaging techniques to determine if these drugs caused actual physical changes to the brain itself, and if there were any cognitive changes that manifested in the patients. The study included 451 patients with an average age of 73 years old. Sixty of the 451 people were taking an anti-cholinergic drug of the type mentioned above. The researchers used brain scans as well as memory and cognitive tests to determine if the drugs caused any changes.

The results demonstrated that there was definite lowered brain activity in the participants who used the anti-cholinergic drugs. There was also lowered activity in the hippocampus, the part of the brain responsible for memory. Not coincidentally, the hipppocampus is the area of the brain that is most affected by Alzheimer’s disease.

In addition, the brains of the anti-cholinergic drug users were SMALLER than the other study participants. It is unclear as to why or how these drugs cause a shrinking of the brain, but the results of this study confirm what has been suspected by scientists all along: that these drugs contribute to cognitive decline and brain shrinkage.


 But This Only Happens at Massive Doses, Right?

Research from 2013 performed at the Indiana University and funded by the NIH demonstrated that it takes just 60 days of taking these drugs at a normal dose for cognitive impairment to occur. 60 days!! That means if you’re taking Benadryl at its recommended dose each day for allergies during the spring, your cognitive functioning will suffer.

So we’re not talking about taking massive amounts here, or even taking the drug for years and years. We are talking about normal doses for relatively short periods of time. And many of these drugs are prescribed or used LONG-TERM, such as Paxil. Scary.

Evidence of the effects of anti-cholinergic activity on brain functioning has been around for quite a while. In the 1990s, researchers published a paper in the American Journal of Geriatric Psychiatry that discussed the link between elevated levels of anti-cholinergics and dementia. A study out just this month in the same journal (June 2016) confirms these findings, demonstrating that in a depressed elderly population, the use of anti-cholinergic drugs is associated with a SIGNIFICANT increase in dementia.

So what drugs do I need to watch out for?

Aging and Brain Care has produced a printable list of all the drugs that have been evaluated. Those with an ACB score of 1 are possibly risky. Those with a score of 2 or 3 are definitely risky.

According to Aging in Brain Care, using drugs with a 2 or 3 score “may increase the risk of cognitive impairment by 46% over 6 years. Additionally, each one point increase in the ACB total score has been correlated with a 26% increase in the risk of death.”

Drugs with ACB of 2 or 3 (definite risk):

  • Benadryl (diphenhydramine)
  • Dimetapp (brompheneramine)
  • Tylenol PM (diphenhydramine component)
  • Thorazine (chlorpromazine)
  • Dramamine (dimenhydrinate)
  • Unisom (doxylamine)
  • Elavil (amitryptaline)
  • Tofranil (imipramine)
  • Zyprexa (olanzapine)
  • Paxil (paroxetine)
  • Phenergan (promethazine)
  • Seroquel (quetiapine)
  • Demerol (meperidime)
  • Tegretol (carbamazepine)

Products with a score of 1, as listed below, are potentially dangerous but their connection to impaired brain function is less clear.

  • Immodium (loperamide)
  • Effexor (venlafaxine)
  • Zantac (ranitidine)
  • Claritin (loratidine)
  • Coumadin (warfarin)
  • Xanax (alprazalome)
  • Abilify (aripiprazole)
  • Wellbutrin (buproprion)
  • Zyrtec (certirizine)
  • Tagamet (cimitidine)
  • Valium (diazepam)
  • Luvox (fluvoxamine)
  • Haldol (haloperidol)
  • Risperdal (risperidone)


Are there Alternatives to Benadryl?

Try using a natural method such as local honey to reduce your symptoms or perhaps visit a local acupuncturist. Acupuncture and Chinese herbs can be very effective in reducing allergy symptoms.  You can also try a homeopathic remedy like Sabadil or Natural D-Hist.

I will be discussing natural remedies for insomnia in a later post. If you are on any prescription drugs that show up on these lists, please discuss your concern with your primary care provider. Many doctors are not aware of these serious side effects, and we need to be informed health care consumers and advocate for ourselves.

Post Author: Hillary

11 thoughts on “Benadryl shrinks your brain. And so do these other common drugs.


    (June 10, 2016 - 12:41 pm)

    Wow, from allergy to dementia? “Nice”… Thank you for sharing this. As someone who has problems with allergies during spring I should be aware.

    I’ve studied research that our brains are shrinking anyway. Reason being the two parts of the brain, one for fast decisions one for deep thinking. In general the one for the fast decision making is larger, but is shrinking because people don’t live in a jungle anymore and are not facing life and death decisions on daily basis. You can read about it if you like:

    Keep posting such good stuff.



      (June 11, 2016 - 12:16 am)

      Interesting, David. I am off to check out your blog. Thanks for stopping by!


    (June 10, 2016 - 11:48 pm)

    Why are these drugs still available on the market? They are really dangerous! You just need to consume the drug for 60 days and you will have dangerous side effects!!More people should learn more about this.


      (June 11, 2016 - 3:00 am)

      Spread the word, Arief! 🙂


    (June 11, 2016 - 2:46 am)

    Wow. That is eye opening. I have taken some of these on this list as well as given some of them to my kids before. I never knew any of this information. When you think about it, it’s pretty scary. I guess we just trust the medicines that doctors recommend and stores sell. More people need to know about this. Thank you for the information.


    (June 11, 2016 - 5:46 am)

    Wow, that’s a shock. I had no idea about the effects of these drugs. It’s good to know there are some natural alternatives though. Thanks for the information!

    Lucas Holloway

    (June 14, 2016 - 10:34 pm)

    This is a really great site. I’ve been looking for a site where I can find information on natural alternatives.
    This article on Benadryl has been well researched and well written.
    Love reading about all this stuff.
    People should be made aware of things like this.

    David Griffiths

    (June 16, 2016 - 1:44 am)

    I like the straightforward academic style to your writing. Too often when I’ve read warnings like the one in this post, the author uses a slightly shrill and hectoring tone. Your presentation is more scientific and factual. It’s especially good to see you provide links to allow readers to verify what you’re saying.

    The problem you’re highlighting is of special relevance to anyone living with the European Union, as the EU has made it more difficult for anyone in member states to offer alternative remedies following successful lobbying from the pharmaceutical industry.


      (June 16, 2016 - 1:49 am)

      Thank you so much for the compliment. So, it’s harder to obtain alternative remedies in the EU? I was recently in London, and there seemed to be TONS of herb shops, homeopathic remedies and acupuncturist storefronts. Is it different in other countries in the EU?


    (June 17, 2016 - 12:03 am)

    I must admit this came as a shock. To think that a common drug (on which the ad is so often shown on TV) can cause dementia is incredible.

    Honestly though, I have never used it myself. But now that you brought this up, I am thinking hard about looking for more natural remedies for the flu.

    Most medicines have side effects but if it can lead to dementia, that’s bad. We want to grow old gracefully – not having to depend on others, right?

    I guess the hardest part is ensuring medicines that you take are really OK and the side effects not too detrimental as to affect your overall being.


    (June 17, 2016 - 2:41 pm)

    Wow, fascinating stuff Hillary. I have pretty bad allergies and I’ve taken a lot of those medications in the past. I had no idea that acupuncture can help relieve allergy symptoms. I’m curious, how does that work exactly?

Comments are closed.