Latest news with #SayantaniSindher
Yahoo
23-05-2025
- Health
- Yahoo
This Common Allergy and Sleep Aid May Be Quietly Raising Your Dementia Risk
If you've ever reached for a quick fix for allergies, a cold, or a sleepless night, chances are you've taken diphenhydramine. It's the active ingredient in well-known over-the-counter meds like Benadryl, Tylenol PM, and many generic nighttime formulas. But National Geographic reported that scientists say prolonged use could come with serious cognitive consequences. Diphenhydramine is one of the most widely used first-generation antihistamines. It's been FDA-approved since 1946 and remains a go-to remedy for everything from seasonal allergies to insomnia. But newer research warns that long-term, daily use may increase your risk for developing dementia or other neurodegenerative conditions. 'Taking diphenhydramine is not without risk, especially as the duration of use increases,' says Dr. Sayantani Sindher, a pediatrician and allergist at Stanford Health Care. Alongside cognitive decline, extended use of the drug has been linked to weight gain, memory problems, and poor sleep quality. Some users also experience anxiety, confusion, or slower reaction times—even when taking recommended doses. The problem isn't just the drug's pharmacology but also its pervasiveness. Diphenhydramine shows up in everything from allergy meds and sleep aids to cold and flu treatments, often without users realizing how much they're taking. 'It's one of the most commonly abused medications in the United States,' says Sindher. According to the Consumer Healthcare Products Association, these medications 'are not intended for long-term use,' and responsible dosing is critical. But for millions of Americans dealing with chronic symptoms, dipping into the medicine cabinet becomes routine, and that's where the risk creeps in. Earlier this year, The World Allergy Organization Journal declared that diphenhydramine is at the end of its life cycle. It suggested that the drug no longer be available over the counter. With safer, non-sedating antihistamines now widely available, doctors suggest reconsidering what's in your daily rotation. Because when it comes to brain health, long-term convenience may not be worth the cost.
National Geographic
19-05-2025
- Health
- National Geographic
The over-the-counter medicine scientists say may raise your dementia risk
Diphenhydramine is the active ingredient in countless over-the-counter medications. But experts say there are serious risks to taking too much of the drug—or taking it too long. Diphenhydramine, a common antihistamine found in over-the-counter allergy and sleeping medications, may increase users' risk for dementia when taken daily over a prolonged period. Experts say the drug can also be harmful if taken in large doses beyond its recommended use. Photograph by EHStock, Getty Images If you're among the one in three adults who struggles with seasonal allergies, the one in 10 dealing with some form of insomnia, or are among the millions dealing with the occasional cold or cough, chances are you've got drugs containing diphenhydramine in your medicine cabinet. But what you may not realize is that for years doctors have been steadily warning against taking too much of the stuff. Diphenhydramine is the active ingredient in countless over-the-counter medications. Originally approved to prevent and treat allergy symptoms, the drug has since become popular for its ability to also treat a range of other issues that include motion sickness, anxiety, cold symptoms, nausea, insomnia, and even Parkinson's disease. Though diphenhydramine certainly has proven benefits, a preponderance of data shows there are reasons to exercise caution when taking it—especially with newer and safer alternatives available. (Scientists knew this drug was useless—but you've been using it for decades.) "Taking diphenhydramine is not without risk, especially as the duration of use increases," says Sayantani Sindher, a pediatrician, allergist, and immunologist at Stanford Health Care. Some of these risks include weight gain, diminished cognitive function, memory impairment, and poor sleep quality. Mounting research also suggests it is linked to higher odds of developing neurodegenerative diseases like dementia. Despite such adverse effects, Sindher calls diphenhydramine "one of the most commonly abused medications in the United States.' She says this is, in part, because it's so prevalent in many over-the-counter formulations that treat countless everyday ailments that "consumers can unknowingly take larger doses than needed." A spokesperson for the Consumer Healthcare Products Association—an organization that represents the over-the-counter medicine industry—told National Geographic that 'it's important to underscore that these products are not intended for long-term use.' Like all medicines, the spokesperson added, 'responsible use is essential.' What is diphenhydramine and how does it work? Developed mid-century by American chemist George Rieveschl and first approved by the U.S. Food and Drug Administration (FDA) in 1946, diphenhydramine is what's considered a first-generation antihistamine. Histamine is a chemical the body's immune system produces as a way of neutralizing allergens and fighting off pathogens. While some histamine is useful, too much can cause unwanted symptoms such as watery eyes, sneezing, coughing, or itchy skin. Antihistamines help prevent this by blocking the effects of histamine—though some antihistamines do so more thoroughly than others. (Here's how different cold and flu drugs work.) For example, newer antihistamines—known as second-generation antihistamines—usually block histamine receptors everywhere in the body except the brain and central nervous system. But first-generation antihistamines like diphenhydramine do the same while also blocking histamine receptors in the brain and central nervous system. When diphenhydramine crosses the blood-brain barrier this way, research shows it affects the body's natural sleep-wake cycle and can trigger feelings of sleepiness. This makes the drug a popular go-to for treating insomnia. Crossing the blood-brain barrier also allows the drug to suppress the medullary region of the brain that's responsible for coordinating the cough reflex—making diphenhydramine also helpful for treating cold symptoms. But this crossing of the blood-brain barrier also blocks another neurotransmitter, called acetylcholine. "Acetylcholine is key to memory, attention, and muscle movements," says Harita Shah, a pediatrician and clinical assistant professor of medicine at the University of Chicago Medicine. This is why diphenhydramine is also considered an anticholinergic—a class of drugs used to treat movement disorders. Such upsides comes with downsides though as taking even recommended doses of diphenhydramine can cause "side effects like drowsiness, confusion, dry mouth, constipation, and trouble urinating," says Shah. Blurred vision and delirium can also occur, though not as frequently. (The spokesperson for the Consumer Healthcare Products Association acknowledged that the common side effects of taking diphenhydramine 'such as drowsiness or dry mouth' are 'well-established.') Other less common side effects include "increased appetite, weight gain, dizziness, postural hypotension, and possible cardiac arrhythmia," says Gordon Sussman, a professor of medicine at the University of Toronto. But what really worries scientists more are some of the more serious emerging risks associated with the drug. For one, studies show that "learning is impacted in young adults taking diphenhydramine,' says Anna Wolfson, an allergist and immunologist at Massachusetts General Hospital and co-author of a 2022 research paper that urges the medical community to 'move on' from the drug. One noted clinical trial demonstrated cognitive impairment when participants who took just a 50-milligram dose of diphenhydramine experienced lower memory retention and difficulty focusing compared to individuals not taking the drug. (The problem with natural sleep aids.) These diminished cognitive abilities can also worsen with age, says Sindher. She explains that the drug remains in older bodies longer than it does in children and adolescents—eventually for as long as 18 hours. "This relatively long half-life risks results in daytime sedation the following day and explains poor concentration and attention," she explains. This is one reason, 'people who take diphenhydramine are more likely to get in car accidents or have more balance-related fractures and other injuries," says Sussman. Increased dementia risk Longer-term use is even more worrisome as multiple studies show that diphenhydramine may also be linked to an increased risk neurodegenerative disease development. This includes a prominent 2015 study published in JAMA Internal Medicine that found that people who took diphenhydramine daily for at least three years had a 54 percent higher risk of developing dementia than people who took the same dose for three months or less. Subsequent Europe-based research and a study from the University of British Columbia demonstrate similar findings. (The reason dementia rates are rising is surprisingly simple.) Although the exact mechanism behind these increased neurodegenerative risks is "still not known," says Shah, the long-term use of anticholinergic medicines like diphenhydramine 'has been shown to permanently alter the brain's structure, neurotransmission capabilities, and chemical pathways." Even if you're only taking the drug for a short time, doctors say you should still be mindful of the risks of overconsumption. "Taking excessive amounts of diphenhydramine within 24 to 48 result in toxicity," says Corey Hannah Basch, a professor of public health at William Paterson University in New Jersey. "A toxic dose can lead to serious symptoms including seizures, confusion, rapid heart rate, hallucinations, urinary retention, and ataxia." Indeed, in the past five years, the FDA has twice had to warn against the "serious heart problems, seizures, coma, or even death" that can accompany taking high doses of diphenhydramine and similar drugs. It did so once in 2020 and again in 2022 in response to social media trends that encouraged people to misuse the drug. Compounding concerns is the fact that no one knows for sure how much diphenhydramine will be toxic. "An 'overdose' would be different for each person," says Wolfson. Basch agrees, noting that "there is broad medical consensus that diphenhydramine toxicity is dose dependent," and that "the severity of symptoms depends on the amount ingested." One commonly cited study shows that worrisome but moderate symptoms of toxicity can occur when taking as little as 0.3 grams of diphenhydramine, but that its most severe symptoms, "including coma and death," Basch says, "were observed at doses of 1 gram or higher." But this higher amount may be much smaller in children, elderly adults, and people with certain medical conditions, Sussman warns. Such concerns are why "several organizations, including the Global Allergy and Asthma European Network, support diphenhydramine being available only as a prescription" and not in its current over-the-counter form, says Jennifer Namazy, a clinical professor of medicine in the division of allergy and immunology at the Scripps Clinic healthcare system in California. Diphenhydramine continues to be FDA approved for certain uses—including treating short-term problems such as "acute treatment of severe allergic reaction" among older populations who are at greater risk of harmful side effects, according to safety criteria from the American Geriatrics Society. But for these people and most of the rest of us, 'the use of diphenhydramine as a first-line treatment for allergic conditions and most other situations is no longer recommended — especially with the wide availability of second-generation antihistamines as an alternative," says Aikaterini Anagnostou, a professor of pediatrics and director of the food allergy program at Texas Children's Hospital & Baylor College of Medicine. Sindher agrees and says that second-generation antihistamines like loratadine (Claritin), cetirizine (Zyrtec), and fexofenadine (Allegra) "have limited, if any, ability to cross the blood brain barrier, which results in fewer anticholinergic side effects." "While diphenhydramine has been trusted for decades, its impairment effects and toxicity potential make it less ideal for routine use," echoes Basch. "It's always wise to re-evaluate longstanding medications like diphenhydramine—especially when newer options offer similar relief with fewer risks."
Vox
15-04-2025
- Health
- Vox
We're on the verge of a universal allergy cure
covers health for Vox, guiding readers through the emerging opportunities and challenges in improving our health. He has reported on health policy for more than 10 years, writing for Governing magazine, Talking Points Memo, and STAT before joining Vox in 2017. If you're bothered by allergies every spring, you may pop a Benadryl or Claritin most mornings to make the days tolerable. Two-thirds of Americans report spring allergies, and about 4 in 10 say they take an allergy medication several times a week. But those medicines, while valuable, don't exactly fix the problem. One 2001 study in the United Kingdom found 60 percent of people who took some kind of over-the-counter medication for allergies reported they were not satisfied with how it managed their symptoms. Nasal sprays are not exactly enjoyable or easy to operate. Allergy medicines have to be taken every day if you deal with serious hay fever, and they can produce, ironically, tiredness for some people during this season of renewal. A missed dose can lead to a day of hacking and sneezing. Oh, and the more you take them, the less likely they are to work. A century ago, antihistamines were a revolution in allergy treatment. But now, we're on the cusp of another. Omalizumab, sold as Xolair, is an asthma medication that was approved more than 20 years ago, but it has proven successful in treating seasonal allergies in recent preliminary trials. So successful, in fact, that now some doctors in the US are prescribing it for certain patients during hay fever season. It is an injection, rather than a pill or a spray, that's given a couple of weeks before pollen and grass levels start to rise. One obvious benefit is you get a single shot and enjoy your spring. But even better, omalizumab can forestall allergic reactions at the source. That means an injection could stop all allergic reactions — not only seasonal allergies but food allergies (such as peanuts) and insect allergies for a prolonged period of time. This class of treatment — monoclonal antibodies, special artificial proteins that carry instructions to the body's immune system — have the potential to be a genuine all-in-one allergy wonder drug. Related The freaky part of allergy season that no one warned you about 'The biggest advantage of antibody-based therapeutics is that they offer the potential to target the underlying pathways driving allergic reactions in general,' said Sayantani Sindher, a clinical associate professor at Stanford University's Sean N. Parker Center for Allergy and Asthma Research. 'This means antibody-based therapies will simultaneously impact all of the patient's allergens.' Large clinical trials are underway in China and Japan, which could lead to omalizumab's approval in those countries for seasonal allergies. The next generation of monoclonal antibody allergy treatments is already in the works. How monoclonal antibodies could stop allergy season before it starts In the United States, the use of monoclonal antibodies started with doctors studying and prescribing preexisting treatments 'off-label' — meaning these are drugs that were actually developed for something else. Asthma and seasonal allergies often occur in tandem, which made omalizumab an obvious candidate for a new approach to allergy treatment. The drug had also separately proven effective in treating food allergies, adding to evidence that it had the right properties to stop seasonal allergies at the source. The treatment has demonstrated significantly better outcomes than antihistamines in small randomized trials, requiring only one dose two weeks before pollen and grass season. A 2022 study reported that patients who received a 300 mg injection of Xolair experienced fewer symptoms and fewer days that required a daily antihistamine or other medication; the patients also reported a better quality of life during the allergy season. Their symptoms were particularly improved during the worst pollen days when compared to the people who only took a daily medication. When pollen and other allergens emerge every year and enter your body through your eyes, ears, or nose while you're enjoying the crisp spring air, your body's immune system overreacts. Immunoglobulin, proteins that are supposed to identify and attack parasites or a virus, instead go after the otherwise harmless allergen. When the immunoglobulin attacks the allergen, your body releases histamine, a chemical critical to inflammation (which, again, is really important when you are actually exposed to a dangerous parasite or virus). That inflammation then creates all that mucus and sneezing. Monoclonal antibodies stop that process before it begins. They deliver artificial proteins that carry instructions to your immune system to block the receptors that create allergic reactions and prevent the overresponse that releases histamine in the first place. Artificially altered antibodies have been around for decades, with different iterations being developed to respond to new health threats. Monoclonal antibodies were developed for Covid-19 during the pandemic and recently provided the platform for an RSV vaccine. Dupilumab (another monoclonal antibody treatment used for skin rashes, asthma, and a lung disease that makes it difficult to breathe called COPD) targets a different receptor but has likewise shown promising results in studies so far. In a large 2018 study, asthma patients who suffer from seasonal allergies received a 300 mg injection every two weeks and showed significant improvements in their nasal blockage. A 2022 study found fewer allergy symptoms among both people with allergic asthma and people without. Monoclonal antibody injections superficially resemble allergy vaccines, which have been investigated more aggressively in recent years. Those shots as well as oral tablets that work in the same way function differently: They expose people to small amounts of the actual allergen, giving their bodies a chance to develop natural immunity to it. They can unlock more durable resistance to specific allergies — but they can only treat one allergy at a time. You may also need to go to the doctor once a week for a month or longer during the initial treatment course. Some companies are trying to make them easier to use. Going forward, the conventional kind of allergy vaccine could still have a place, particularly for patients who are at particularly high risk of developing asthma, by strengthening immune systems for the longer term; monoclonal antibodies, by contrast, do not actually modify the immune system in the same way, so they would need to be taken again periodically. But Sindher emphasized the potential to treat all allergies at once as an obvious advantage for monoclonal antibodies over immunotherapies. 'Pollen allergy and food allergy are frequently found together,' she said. 'Omalizumab has the potential to treat both.' With monoclonal antibody shots, patients also report fewer side effects. There is a subset of people for whom antihistamines don't work, including those who have built up a tolerance to those drugs after frequent usage. These new monoclonal antibodies may help them where those old treatments are now failing. Specially tailored allergy-specific products are now in the works, ushering in this new era of allergy treatment. In early April, the final stage of one clinical trial found the following results after four weeks: Patients who had still reported symptoms after taking the standard-of-care treatment and then received a monoclonal antibody injection were much more likely to report mild or no nasal symptoms (62 percent) than people who were taking the placebo (39 percent). They scored significantly better on oral symptoms and other measures of efficacy without serious side effects. The drug in the clinical trial, Stapokibart, was recently approved for seasonal allergy treatment in China, and its developer, Keymed, has premised its business on developing and gaining approval for treatments in that country and then bringing them to the US. Monoclonal antibodies will continue to make inroads as more products come to the market. A new era for allergy treatment Monoclonal antibodies, by offering months of allergy relief in just one injection, could elide one of the biggest challenges in all pharmaceutical treatments: making sure people take medicines like they are supposed to. What to ask your doctor Omalizumab is a promising new treatment for seasonal allergies, but the FDA has not specifically approved it for seasonal allergy care yet. So far, doctors have been prescribing this 'off label' — meaning it has proven safe to use for a different purpose, but the science on its effectiveness for allergies is preliminary. A prescription is ultimately at your doctor's discretion, but if you suffer from severe allergies, it could be a fit for you. Here are some things to consider asking your physician if you're interested in this kind of treatment: Are there other existing treatments they would advise trying first? Do I have another condition for which Xolair is intended to treat? What steps should we take for my health plan to cover the cost? With antihistamines and nasal sprays, you must regularly buy them yourself and repeatedly remember to take them correctly to stave off allergy symptoms. That 2001 study in the UK found that many people who suffered seasonal allergy symptoms nonetheless did a poor job of taking medication as they should: Among the 54 percent of people who were experiencing poor allergy symptoms, 70 percent didn't use the conventional allergy medicines according to the clinical guidelines. But for allergy sufferers to make the jump from something like Claritin to an annual allergy shot that works even better, health insurance coverage will be critical: The list price on omalizumab is $1,500 a pop. This would be a new cost to health plans because patients often bear their own over-the-counter antihistamine med costs. Off-label coverage of any drug, including omalizumab for seasonal allergies, can be fickle. Some popular plans, such as United Healthcare, are not currently covering the drug for that use at this time because they consider it unproven. As more research comes in and more products come on the market, the insurers' value proposition may change. The FDA recently approved a generic version of omalizumab, which should help reduce prices for that injection. As they do, they could offer more value for the patients for whom conventional therapies aren't working. Seasonal allergies can significantly diminish a person's quality of life — during what should be one of the most enjoyable times on the calendar — and they come around every year.
