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Which Antihistamines Are Linked To Dementia

Find Out Which Drugs Are Anticholinergic

Certain medications linked to Dementia

You may not be familiar with the term anticholinergic when it comes to medication. But this type of pharmaceutical medication is very common, and you might even have some in your home right now. They block the chemical acetylcholine from transmitting messages from nerve cells to other cells of the body, which affects muscle contractions and areas of the brain involved in learning and memory.

Milder anticholinergic drugs include those used to treat gastrointestinal disorders and antihistamines like Benadryl. But those are less worrisome at this point, since they were not found, at least in this study, to raise dementia risk. Cognitive problems, however, were shown to be associated with the longer-term use of stronger forms of anticholinergic medications, such as antidepressants, bladder antimuscarinic drugs, epilepsy medications, and drugs to treat Parkinsons disease symptoms.

Is Loratadine An Anticholinergic


. Correspondingly, does loratadine cause dementia?

Long-term use of Benadryl, an over-the-counter allergy medication, has been linked to an increased dementia risk. In lieu of Benadryl, possible alternatives include cetirizine , fexofenadine and loratadine .

Beside above, which antihistamines are anticholinergic? Antihistamines with anticholinergic properties include the following:

  • Chlorpheniramine.
  • Promethazine.

Similarly one may ask, is Claritin an anticholinergic?

And when it comes to allergies, there are many alternatives to Benadryl, an anticholinergic and so-called first generation antihistamine. Second- and third-generation antihistamines, including brands such as Claritin, Zyrtec and Allegra, are not anticholinergics. But talk to your doctor before switching to a new drug.

Which antihistamines are linked to dementia?

Some specific anticholinergic drugs are:Older antidepressants like doxepin Antimuscarinics for bladder control like oxybutynin First generation antihistamines like diphenhydramine and chlorpheniramine .

What Should You Do About Benadryl And The Risks Of Dementia

In 2008, Indiana University School of Medicine geriatrician Malaz Boustani developed the anticholinergic cognitive burden scale, which ranks these drugs according to the severity of their effects on the mind. Its a good idea to steer clear of the drugs with high ACB scores, meaning those with scores of 3. “There are so many alternatives to these drugs,” says Dr. Berry. For example, selective serotonin re-uptake inhibitors like citalopram or fluoxetine are good alternatives to tricyclic antidepressants. Newer antihistamines such as loratadine can replace diphenhydramine or chlorpheniramine . Botox injections and cognitive behavioral training can alleviate urge incontinence.

One of the best ways to make sure youre taking the most effective drugs is to dump all your medications prescription and nonprescription into a bag and bring them to your next appointment with your primary care doctor.

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Can Allergy Medications Harm Your Brain

It’s allergy season and many of us will be reaching into the medicine cabinet for relief. But it is important to choose wisely, as some allergy medications can harm brain health and increase dementia risk.

Diphenhydramine is a first-generation antihistamine medication . In addition to treating allergy and cold symptoms such as sneezing and watery eyes, it also blocks the actions of acetylcholine. This is a neurotransmitter that is important for brain functions including learning and memory. Diphenhydramine is classified as an anticholinergic drug, and a study of this class of drug found that increased use is associated with an up to 54% increased risk of dementia .


The good news is that newer antihistamines equal the effectiveness of diphenhydramine with few or no cognitive side effects. These medications were developed to minimize adverse events common to diphenhydramine and other older antihistamines .

If you’re older or have concerns about brain health, consider an allergy medication other than diphenhydramine. In addition to the medications above, topical nasal sprays and allergy shots are available by prescription and can also help alleviate symptoms. As always, it’s a good idea to discuss your options with a medical professional.

  • Bower EA, Moore JL, Moss M et al. The effects of single-dose fexofenadine, diphenhydramine, and placebo on cognitive performance in flight personnel. Aviat Space Environ Med 74, 145-152.
  • Antihistamines Part Ii: Long

    Popular OTC Benadryl

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    The last Pharmacology Consult column, Antihistamines for the common cold: Wheres the evidence? , reviewed recently published data suggesting that antihistamine product use may be increasing for the treatment of common cold symptoms. Because recent recommendations and regulations have decreased the use of cough/cold products in the pediatric population, pediatric health care providers may be turning to antihistamine-based products instead. Commonly used first-generation antihistamines have strong anticholinergic properties, and recently published data from the adult population have suggested that long-term use of these drugs may increase the risk for developing dementia. As summaries of these publications find their way to the lay media, it is understandable that parents may wonder about the long-term safety of using antihistamines in children. Although the diagnosis of dementia is certainly not associated with the pediatric population, parents may still express concern about the adverse effects and long-term safetyof antihistamines.

    Second-generation antihistamines , considered nonsedating because of their relative lack of CNS penetration, are commonly prescribed to children and adults for allergic conditions. Second-generation antihistamines display no significant anticholinergic pharmacologic actions.

    Anticholinergic drugs and dementia risk


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    People Should Not Stop Their Therapy But Talk To Their Health Care Provider

    Prof. Gray urges people not to stop their therapy based on the findings of this study they should talk to their health care provider, and also tell them about all their over-the-counter drug use.

    Health care providers should regularly review their older patients drug regimens including over-the-counter medications to look for chances to use fewer anticholinergic medications at lower doses, she says.

    If providers need to prescribe anticholinergics to their patients because they offer the best treatment, then they should use the lowest effective dose, monitor the therapy regularly to ensure its working, and stop the therapy if its ineffective, she adds.

    Although the link between raised risk of dementia and anticholinergics has been found before, the new study uses more rigorous methods including over 7 years of follow-up to establish the strength of the link. By accessing pharmacy records, the researchers were also able to include non-prescription use of anticholinergics in their data.

    It is also the first study to show a dose-response effect, note the authors. That is, the higher the cumulative amount of drug taken, the higher the risk of developing dementia.

    And another first for the study, is that it also shows that dementia risk linked to anticholinergics may persist long after people stop taking the drugs.

    Benadryl Still Widely Used After Study Linked It To Alzheimer’s

    Benadryl is still widely used six years after a study linked it to Alzheimer’s disease.

    Given how much excitement there’s been about Aduhelm, a new drug recently approved to treat Alzheimer’s disease and how much money people spend on all kinds of unproven treatments, you’d think strong evidence linking certain popular drugs to the dread disease would get a lot of attention.

    But strangely, that’s not the case. It’s been more than six years since researchers in Seattle found a “significantly increased risk” of Alzheimer’s and other dementias among people who have taken Benadryl , a popular over-the-counter drug used for the relief of allergy symptoms. But instead, sales of the venerable drug continue to be robust, ranking number five among OTC antihistamines, according to Statista.

    “Older adults should be aware that many medications–including some available without a prescription, such as over-the-counter sleep aids–have strong anticholinergic effects,” said Shelly Gray, PharmD, MS, when the report was issued in January 2015. “And they should tell their health care providers about all their over-the-counter use,” she added, in a news release.

    Anticholinergic drugs block the action of neurotransmitter chemicals released by nerve cells to send signals to other cells, possibly interfering with memory and cognition.

    “No one should be using Benadryl as a routine allergy medication.” — Roy Benaroch, M.D.

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    Which Drugs Are We Talking About

    Anticholinergic drugs include the antipsychotic clozapine the bladder drug darifenacin the anti-nausea drug scopolamine the bronchodilator ipratropium the muscle relaxant tizanidine antihistamines such as diphenhydramine , and antidepressants such as paroxetine .

    These medications work by blocking a chemical called acetylcholine, which acts as a neurotransmitter and is involved in many nervous system functions including muscle movements, heart rate, the widening of blood vessels, respiratory functions and muscle contractions in the stomach during digestion.

    Older adults are more likely to be prescribed many of these medications, simply because they tend to have more health issues. Some experts say that because people produce less acetylcholine as they age, drugs that inhibit that neurochemical can have a stronger effect on older people.

    What The Study Found Regarding Benadryl And Dementia

    Antihistamines lead to Dementia and Death

    A team led by Shelley Gray, a pharmacist at the University of Washingtons School of Pharmacy, tracked nearly 3,500 men and women ages 65 and older who took part in Adult Changes in Thought , a long-term study conducted by the University of Washington and Group Health, a Seattle healthcare system. They used Group Healths pharmacy records to determine all the drugs, both prescription and over-the-counter, that each participant took the 10 years before starting the study. Participants health was tracked for an average of seven years. During that time, 800 of the volunteers developed dementia. When the researchers examined the use of anticholinergic drugs, they found that people who used these drugs were more likely to have developed dementia as those who didnt use them. Moreover, dementia risk increased along with the cumulative dose. Taking an anticholinergic for the equivalent of three years or more was associated with a 54% higher dementia risk than taking the same dose for three months or less.

    The University of Washington study is the first to include nonprescription drugs. It is also the first to eliminate the possibility that people were taking a tricyclic antidepressant to alleviate early symptoms of undiagnosed dementia the risk associated with bladder medications was just as high.

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    Benadryl And Other Common Medications Are Linked To Dementia In Men And Women

    Many people turn to over-the-counter medicines when they need relief from allergy and cold symptoms or have trouble falling asleep. Thats why you might be concerned about a 2015 study showing that one of the most common of those drugsBenadrylcould lead to serious health problems, including dementia.

    Benadryl has many uses. Although often taken for allergy symptoms, the same dose of the same ingredient is used in most over-the-counter sleeping pills, and also used for motion sickness. Weve known since 2012 that people who regularly take Benadryl or other sleeping pills to fall and stay asleep are more likely to get cancer and tend to die earlier than people who dont take sleep medication. A 2015 study, however, found that taking Benadryl also seems to increase a persons chances of developing dementia.

    Most people who take Benadryl dont even know it, since the pills they buy in their local drug stores have many different names . Drugs containing diphenhydramine arent the only ones linked to an increased risk of dementia. The 2015 study, led by a researcher from University of Washington, found an increase in dementia linked to a type of drug known as anticholinergics. These drugs are known to help dry out a runny nose or tearing eyes and also to make you sleepy they work by blocking acetylcholine, a chemical that sends messages to and from the brain and helps start muscle contractions.

    Considerations For Future Research

    Adjusting for time varying confounders is difficult in a matched case-control study.3146 We measured covariates at the start and end of the drug exposure period . Since there was little difference between these estimates in most cases we are confident that the effect of time varying covariates does not considerably affect our findings. Secondly, to be certain that potential confounders preceded drug initiation and not vice versa, we further excluded patients who were prevalent users at the start of each DEP, again with little difference in results. We suggest that authors undertaking case-control studies comparing cumulative exposure over a long period carefully consider how time varying covariates and exposure before the period in which they are being directly measured might affect study findings. Future research into the potential harms of anticholinergics must consider differential effects of individual drug classes and their potentially different mechanisms of action. Carefully conducted prospective studies in specific cohorts of patients comparing the long term cognitive effects and neuropathological correlates of specific drug classes are needed.

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    Confirmed Earlier Alzheimer’s Studies

    Earlier studies had found the link between Benadryl and Alzheimer’s but the Seattle study used more rigorous methods, longer follow-up , and better assessment of medication use via pharmacy records to confirm the link.

    The study, published in JAMA Internal Medicine, was also the first to show a dose response, linking more risk for developing dementia to higher use of anticholinergic medications. And it was also the first to suggest that dementia risk linked to anticholinergic medications may persist–and may not be reversible even years after people stop taking the drugs.

    Are Anticholinergic Drugs Harmful

    Antihistamine Linked to Dementia

    Scientists and doctors have known for quite some time that anticholinergics carry risks in seniors, according to Gray.

    ” can cause a range of side effects such as constipation, difficulty with bladder control,” she said. “They can cause acute changes in cognition, meaning slight changes in cognition, and delirium. More recently, there is mounting evidence that they might be linked to dementia.”

    The risk, according to the study, is only associated with 1,095 daily doses taken within a 10-year period, which is equivalent to taking a strong anticholinergic medication daily for at least three years.

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    What Did The Research Involve

    The research team analysed data on 3,434 US people aged over 65. These people had no dementia at the start of the study.

    The study’s participants were tracked for an average of 7.3 years to see who developed dementia or Alzheimer’s disease.

    The researchers also gathered information on what anticholinergic medications they were prescribed in the past as well as a partial record of past OTC use.

    The researchers’ main analysis looked for statistically significant links between these prescribed medications taken in the past 10 years and the likelihood of developing dementia or Alzheimer’s disease.

    Cases of dementia and Alzheimer’s were first picked up using a test called the Cognitive Abilities Screening Instrument, which was given every two years.

    This was followed up with investigations by a range of specialist doctors, and laboratory tests, to arrive at a consensus diagnosis.

    Medication use was ascertained from a computerised pharmacy dispensing database that included the name, strength, route of administration , date dispensed, and amount dispensed for each drug. This was linked to each individual’s electronic record at Group Health Cooperative, a US health care and insurance system, plan so it was personalised.

    This cumulative exposure was defined as cumulative total standardised daily doses .

    The statistical analysis adjusted for a range of potential confounders identified from past research, including:

    Higher Dementia Risk Linked To More Use Of Common Drugs

    Group Health Research Institute
    A large study links a significantly increased risk for developing dementia, including Alzheimer’s disease, to taking commonly used medications with anticholinergic effects at higher doses or for a longer time. Many older people take these medications, which include nonprescription diphenhydramine .

    A large study links a significantly increased risk for developing dementia, including Alzheimer’s disease, to taking commonly used medications with anticholinergic effects at higher doses or for a longer time. Many older people take these medications, which include nonprescription diphenhydramine . JAMA Internal Medicine published the report, called “Cumulative Use of Strong Anticholinergic Medications and Incident Dementia.”

    The study used more rigorous methods, longer follow-up , and better assessment of medication use via pharmacy records to confirm this previously reported link. It is the first study to show a dose response: linking more risk for developing dementia to higher use of anticholinergic medications. And it is also the first to suggest that dementia risk linked to anticholinergic medications may persist — and may not be reversible even years after people stop taking these drugs.

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    Q If Youre Someone Who Is Taking These Medications What Should You Do

    A. We recommend you takethese steps if you have any concerns:

    • Speak to your doctor or geriatric team before you stop taking these medications: If you suddenly stop taking certain medications, you may experience worsening effects. Your provider can determine whether the medication should be tapered and may also be able to recommend safer substitutions you can use in their place or non-medication treatment options you can try.
    • Be informed and ask questions: You may have been on a medication for years that youve tolerated well. But its fair to continually reevaluate your medications. Your body doesnt metabolize and respond to medications the same way it did 30 years ago. So bring your questions to your provider to help start the conversation.
    • Speak with your provider about any over-the-counter medications youre taking: Those medications still can have side effects and may be doing more harm than good. You can either ask your geriatrician or your pharmacist.

    Devastating Consequences Of Dementia

    Research Links Allergy Medications With Dementia

    Given the devastating consequences of dementia, informing older adults about this potentially modifiable risk would allow them to choose alternative products and collaborate with their health care professionals to minimize overall anticholinergic use,” the JAMA report cautioned.

    But for whatever reason, the study didn’t receive the front-page attention normally devoted to promising new treatments for dementia, many of which never get beyond the promising phase. It is mentioned now and then, but mostly in publications for medical professionals and those in related fields, like a 2019 article in the Harvard Health Blog.

    “One long-ago summer, I joined the legion of teens helping harvest our valleyâs peach crop in western Colorado,” wrote Beverly Merz, executive editor of Harvard Women’s Health Watch. “My job was to select the best peaches from a bin, wrap each one in tissue, and pack it into a shipping crate. The peach fuzz that coated every surface of the packing shed made my nose stream and my eyelids swell,”

    Merz’s family doctor fixed her up with some Benadryl and Merz wrote that she was very thankful for the relief it offered.

    “Today, Iâm thankful my need for that drug lasted only a few weeks,” she wrote, saying that Gray’s study offered “compelling evidence of a link between long-term use of anticholinergic medications like Benadryl and dementia.”

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